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KB L1-3 Flashcards

1
Q

What three transcriptional regulators make cells specific?

A

Epigenetics
Trans- acting elements
Nc-RNA

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2
Q

Drosophila is advantageous to study development because? (6)

A 
Small
Short generation time (9 days)
Lots of mutant Phenotypes 
Fate maps available for certain areas 
Only around 13,000 genes
Complete genome sequence available
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3
Q

What other model systems are there (than dros?)

A

Nematode worm - simplest organism with a nervous system
Zebra fish - embryo is visible during development
Mouse - common mammal due to sequencing o

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4
Q

General structure of a transacting domains

A

DNA binding domain with ATTA binding motif

Transregulatory domain, interacts with other components of the transcription machinery to help regulate gene expression

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5
Q

Stages of drosophila development

A 
Day 0 - fertilisation 
Embryonal development
Day 1 hatching 
Larva - 3x larval stages with Sep motifs
Day 5 pupation
Pupa
Metamorphosis
Day 9 adult
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6
Q

What time frames are transcription factors influencing developmental decisions?

A

Integration of long and short signals through the action range of the transcription factors

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7
Q

Order of drosophila segmentation

A

Egg-polarity genes (bicoid) - head and tail are defined, maternal effect genes
Gap genes - Kruppel and Hunchback - expressed in larger overlapping domains
Pair-rule (Evo and ftz) - define seven segments each so get 14 segments
Segment polarity genes (engrailed) - anterior and posterior of each segment, expressed in each of the 14 segments
Hox genes - tells segment what they are going to become. Defining the areas of the organism ie thorax and abdomen

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8
Q

If you delete drosophila segment genes what happens

A

The are where the genes were expressed will be missing and the expression of genes down stream of the mutation will be affected showing a hierarchy of gene expression

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9
Q

What does Evo stand for?

A

Even-skipped

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10
Q

What results in evo being turned on?

A

Several types of signalling. Pathway in a cluster of mesodermal cells

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11
Q

What tissue develops cells expressing evo and what does it go on to make?

A

Muscle develops cells expressing evo and goes on to make heart and body wall muscle

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12
Q

what is evo regulated by in mesoderm?

A

An enhancer, and within the enhanced there are sites that bind regulatory factors that are at the end of receptor tyrosine kinase signalling pathways and regions that bind to factors from wingless and decapentapleigic signalling systems plus a binding site for twist (specific to undifferentiated mesoderm) and tinman (marker for dorsal mesoderm cells)

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13
Q

What did halfon et al show about binding sites in the evo enhancer?

A

By mutating the binding sites halfon shows that they are all needed to achieve proper expression of evo. The signalling and receptors is like a code deciphered by the enhancer

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14
Q

There is homology between genes that control organ formation in humans and flies what does this mean?

A

That we can study flies as model organisms for organ development

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15
Q

What mutant phenotype led to the formation of hox genes?

A

Antennapedia

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16
Q

What do all bilateral animals possess?

A

A common genetic mechanism for patterning the A/P axis involving the hox cluster

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17
Q

Properties of the homeodomain

A 
183bp,
Very basic protein domain 30% K and R 
Secondary structure is HTH motif 
Hox TF bind ATTA 
One of the helices sits in the major groove making contact with the bases
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18
Q

Structure of a typical homeodomain

A 
Variable region
Homopeptide (highly conserved) 
Intron 
Homeodomain 
Acidic tail
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19
Q

In hox LOF transformations mutants what happens?

A

Affected body structures resemble of anterior ones.

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20
Q

What are gof mutant hox Phenotypes due to?

A

ectopic expression of more posterior hox genes which are capable of cancelling out the function of more anterior ones

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21
Q

What is an example of posterior prevalence?

A

Abd-A is the posterior most region of the fly embryo. When under control of a heat shock promoter all head and thoracic segments attain a more posterior like identity

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22
Q

What occurs on hoxc8 -/- mutant

A

= attachment of the 8th pair of ribs to the sternum and appearance of a 14th pair of ribs on the first lumbar vertebra

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23
Q

What is ubx protein

A

Ultrabithorax identified by mutations that transform halteres (balancing organs in flies) into an extra pair of wings

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24
Q

What does ftz activate?

A

Ubx and antp

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25
What does ubx protein activate/repress?
Activated ubx and represses antp
26
If you use a heat shock promoter to express antp in the drosophila germline what happens?
Antenna to leg Homeric transformation
27
How are homeodomain containing TFs specific - 2 ways?
By dimerisation to cofactors (however this is not enough to explain the specificity of hox genes and enhancers are also important I increasing specificity)
28
What is the role of the cofactor exd in flies and what is its homologue in mammals?
Exd - extra dentide, loss = loss of most segmental differentiation with no apparent change in hox expression Pbx is the homologue in mammals
29
How many hox clusters are there in drosophila?
2 clusters | The antennapedia complex and the bit borax complex
30
How is animal patterning ie, dorsal/ventral patterning genetically conserved?
By TGFβ family members dpp in dros and BMP4 in vertebrates | And their interacting ligands sog and chordin.
31
What is co-linearity?
Where the position of the gene in the genome corresponds to where the gene is expressed in the embryo
32
How many classes of homeobox genes are there
20 | Hox is one class
33
Similarity in homeodomains between vertebrates and invertebrates?
A homeodomain in frog has 1 as different to that in a fly and the path of divergence between these organisms occurred around 500million years ago
34
What chromosome is hox a Hox b Hox C And hox d on?
A- c7 B - c17 C - c12 D - c2
35
How do similar genes align in hox clusters?
In paralogous groups ie A4 is more similar to B4 and D4 than A3 and A5
36
How many duplications of hox clusters in mammals?
2 to give 4 clusters
37
What happens if you swap paralogous hox coding regions? | What happens on swapping non coding regions and what does this suggest?
Swapping b4 for a4 etc there is little effect on development Non coding regions are moved this disrupts development, suggesting that whist the genes are similar they are expressed differently spatiotemporally and this involves non coding regions
38
What hox rearrangements cause leukaemias?
MLL/AL1/HRX
39
Action of trxG and pcg on hox genes?
They repress/activate hox genes on A/P body axis
40
In a mouse hox genes are expressed in the abdomen what happens on trxG and pcg mutants?
TrxG: diminished hox gene products Pcg: hox genes expressed in abdomen, thorax and head
41
What is the role of krox20 in mouse hindbrain development?
A transcription factor that activates hoxB2 in the hindbrain of the developing mouse. It is expressed in odd number rhombomeres 3&5
42
What is krox20 in mammals and what happens on KO
Egr2 KO R3 looks like r2 and r5 looks like r6
43
What is a good system for showing colinearity?
The hindbrain of the mouse and hoxb2-b5 expression
44
Can you drop a hox gene randomly into the genome and expect correct expression?
No, there are complex local and distal control elements
45
What dros genes are there no equivalent of?
The gap and the pair-rule genes
46
What do chromatin modifiers do to hox genes in ESC?
Repress them (pcg and ncRNAs)
47
Describe hox gene expression in development
Initially in development hox genes are switched off (global silencing) they become progressively activated during development following a temporal sequence that correlates with the genes position in the cluster in a 3'-5' direction - temporal colinearity
48
How is hox gene expression switched on and maintained?
By PcG and trxG systems
49
Why is the temp rial nature of colinearity important?
Because even if the end product is maintained, but the temporal expression is incorrect there are phenotypic changes
50
In ESCs how are hox genes labelled and what happens on expression of hox?
They are bivalently labelled. Down reg of H3K27me3 Up reg of H3K4me3
51
What removes H3K27me3 marks?
Kdm6 and Kdm6a
52
How are hox genes moved physically into an activated domain?
Shunted into active domain one at a time. Genes are segregated into a separated domain as they are activated but they maintain interactions with the cluster - linear sliding. This 3D nature suggests that the location within the nucleus may also affect hox gene expression
53
What does cis- regulation of hox genes do?
Control their transcriptional patterns and are a major determinant of hox gene spatial expression
54
What is cis-regulatory activity independent of?
Hox genes being located in a hox cluster.
55
What is spatial control of hox gene expression seem mostly independent of?
Genomic arrangement. In organisms where hox genes are not clustered hox expression still maintains spatially colinear gene expression.
56
Example of where hox genes are not clustered and still maintains co- linear gene expression. And is this generally the case?
D. Buzzatti has two distinct splits in hox genes compared with D. Melanigaster but changes don not seem to lead to any significant differences in hox gene expression arguing that integrity of gene compels is not an absolute requirement for establishment of hox expression patterns However, many links between colinear activation being linked to clusters which may in part be due to compact structure of the hox loci.
57
What is the relationship of hoxD11 and 12 with PRC2?
Seem to be involved in homing PRC2 to the hoxD cluster. But removal from mouse genome does not appear to have any deleterious effects on development or on hoxD expression in mouse embryo
58
What does retanoic acid do to methylation patterns and cell state?
Decrease in H3K27me3 and increase in H3K4me3 | Causes undifferentiated to differentiated and 24/36 hox genes to be expressed in differentiated cells
59
How does Ret acid affect spatiotemporal expression of hox genes?
Timing 3' first 5' last Sensitivity 3': most sensitive to RA 10-8 5': least sensitive 10-5 so 3' End genes can switch on at the lowest concentrations
60
What factors affect hox expression like RA?
Wnt, FGF and gdf11
61
What would the gradient if RA explain
Co-linearity
62
Ectopic expression of hoxa7 Hoxa4 Hoxd4 in mice
Hoxa7 - craniofacial abnormalities and homeotic transformations of vertebrae axis and atlas switch Hoxa4 - mega colon, innervation in colon prevented, cannot express faeces Hoxd4 - homeotic transformations of skull bones
63
Knockout by homologous recombination of hoxa3, hoxc8
Hoxa3 - severe head and throat abnormalities | Hoxc8 - homeotic transformation of vertebrate
64
When does a double hox knockout give a more sever phenotype?
Hoxa11 or hoxd11- regional bone abnormalities Hoxa11 AND hoxd11 - radius and ulna missing homeotic transformations of vertebrae and sever kidney defects Paralogues seem to have some sort of functional redundancy built in
65
Naturally occurring hoxd13 mutation?
Human: synpolydactyly (6 fingers) co segregated with a 15 residue polyalanine stretch in exon 1 of hoxd13 gene. Gain if function mutations Increase in penetrance and severity with increase in expansion size Semidominant mutation Aa mild phenotype AA severe phenotype
66
What do 2 different hoxd13 deletions do?
Result in premature stop codons and have been assoc with some synpolydactyly phenotype and foot malformation. Such truncations would eliminate function of hoxd13 protein suggesting the SPD phenotypic variant was due to haploinsufficiency for the hoxd13 gene
67
Hoxa13 natural mutation:
Human: hand-foot-genital syndrome, dominant nonsense mutation in homodomain generate a truncated protein unable to bind DNA. Haploinsufficiency leading to phenotype
68
Hoxa13 deletion in mice leads to?
Hyopolydactyly - deformed paws. Suggests paralogues are important for hand/foot development and affect other genes required for hand/foot development.
69
Role of the lncRNA HOTAIR in hox gene expression
HOTAIR is transcribed between hoxc11 and hoxc12 and blocks genes in the posterior hoxD cluster. HOTAIR targets PRC2 and LSD1 to specific areas of hoxD HOTAIR conservation between mice and humans is low, removal in mice has no negative effect on embryonic development or h3k27me3 pattern changes
70
Hoxa9 in cancer?
AML t(7;11) NUP98 fusion with hoxa9 - temperospatial deregulation and hoxa9 over expression
71
Hoxa5 in breast cancer
Hoxa5 regulates p53 Hoxa5 promoter is hyper methylated leads to p53 decreased expression and also RARβ normally triggers apoptosis through caspases 2&8 so leads RARβ means less apoptosis
72
Hoxb13 over expression is associated with what in cancer?
Is associated with tamoxifen reaistance in ER+ primary tumours
73
Pax genes were found in dros: characteristics?
Contains 128 amino acid paired box, found in other proteins. DNA binding domain Dros: paired gene Mammalian homologue : PAX 4 groups based on structural similarities and patterns of expression Non clustered With or without a homeodomain and an octapeptide
74
How does the paired domain bind DNA?
It has two subdomains that interact with the DNA sequence GTTCC PD And HD are transcriptional regulators
75
What are THDs?
Impacted homeodomains that are shorter than traditional HDs
76
Is there functional redundancy in pax?
No only 9 pax genes and four subgroups
77
Why is pax important in CNS development?
Cross regulatory feedback loops are thought to maintain and stabilise developing regions of the brain and spinal cord so that aberrant pax expression overturns neuronal fate
78
What is the general role of pax?
Maintenance of progenitor cells - prevent differentiation
79
Group I pax 1 mutations
Mouse undulated tail - kinked tail no human equivalent | Abnormalities of vertebrae
80
GrI PAX 9 abnormalities
Implicated in oesophageal cancer - good prognosis | Mutation leads to oligodontia - missense mutation (in mice, lots of muts including no teeth)
81
GrII PAX2 mutations
Renal-coloboma syndrome (human) | Optic nerve tumours, kidney and ear defects
82
Group II PAX 8 defects
Follicular thyroid tumours (somatic pax8 mutations) | t(2;3) produces pax8:PPARγ fusion protein (activated oncoprotein)
83
PPARγ is usually what?
A growth retarding protein the translocation to fusion protein may inhibit this and prevent apoptosis the PAX8:PPARγ fusion is overtly invasive compared to those cancers without
84
Group II pax5 mutations
Implicated in B cell development | Large cell lymphomas in humans t(9;14) puts pax5 next to IgH gene a strong promoter - up reg of pax5
85
When are the group 2 of genes required?
In very early brain development and segmentation but are transcriptionally down regulated before birth
86
How do pax genes carry out developmental transitions of progenitor cells
By acting in regulatory networks often controlling the balance of prolif and diff of progenitors
87
Germline pax3 mutations
Pax 3 is essential for neural crest development | Pax3 muts get splotch mutant in mice abnormalities of pigmentation and neural tube defects
88
Pax3 muts in humans
Waardenburg syndrome, pigmentation defects, deafness, eye defects, germline mutation gives inherited defects analogous to splotch in ferret
89
Pax7 upregulates?
Snail, foxd3 and sox genes downstream neural crest specifier cells
90
In splotch mice what do neural crest cells fail to undergo?
Proliferative expansion prior to migration due to defects intrinsic to the neural crest
91
Somatic pax3 mutations
- alveolar rhabdosarcoma and aggressive childhood muscle tumour where cells resemble alveoli t(2;13) translocation gives pax3-fkhr fusion and 100 fold gof effect on pax3 downstream targets and a dominant negative effect on WT pax expression
92
Somatic Mutations in pax7
t(1;13) gives similar pax7-fkhr fusion | Similar diseases.
93
Tinman human homologue | Effect of KO in dros and human expression
HH: Nkx2.5/csx KO tinman in fly: dead larvae, missing dorsal vessel and other dorsal mesoderm derivatives Nkx2.5 : expressed in fetal heart primordia. Mutation leads to embryonic lethality and embryonic heart development is arrested at initial stage of heart looping It would seem the underlying genetic mechanism for blood pumping organ is well conserved
94
Pax6 mutation in mouse:
Small eye mutant
95
Pax6 mutant in humans and dros analogue
Aniridia, WAGR syndrome | Dros - eyeless
96
How widely conserved is pax6?
Present in triphoblastic animals ie flatworms / nematodes | Deep conservation as photoreceptor proteins are used by all animals even if eye organisation has changed
97
What is pax6 promoter subject to?
Methylation in some human tumours perhaps silencing prevents tumour suppression and contributes to tumourigenesis
98
Where were zinc fingers discovered
In a frog transcription factor
99
Characteristics of zinc fingers:
DNA/ RNA binding domain with a cys+his or a cys+cys bindin a zn2+. These coordinate zinc in a tetrahedral fashion. Zn finger helices interact with the major groove of the DNA. You can predict Zn finger binding due to the amino acid side chains. Multiple Zn fingers gives DNA binding specificity
100
What are the four types of Zn finger gene subclasses and the Zn coordinating amino acids?
TFIIA - CC/HH nuclear hormone receptors CC/CC retroviral GAG products CC/CH yeast transcriptional factors 6xC coordinate 2 Zn ions
101
Developmental gene example of a zinc finger
Kruppel Drosophila is a gap gene that regulates pair-rule genes. Mutations in Kruppul lead to developmental problems
102
What is Gli3?
A zinc finger gene at the end of sonic hedgehog signalling pathway which is important in development Mouse: extra toes mutant Human: Grieg syndrome - skeletal malformations of hands feet and cranium (fuses early preventing proper brain dev)
103
Wt1 as a zinc finger gene
Deletion in WAGR syndrome. Human: WAGR and drash Wt1 is important in genutounrinary tract development
104
Pou genes are:
Regulators of development expressed in early embryogenesis and during forebrain development. Critical transactivators POU genes are expressed in distinct spatiotemporal patterns in the forebrain an area that does not express classic HD genes
105
3 POU genes and organism of discovery
Pit1 - rat Oct1/2 - human Unc86 - nematode
106
All POU genes have what?
A POU homeodomain (60aas) and a POU specific domain (DNA binding domain 74-82aas) separated by a spacer of 15-27aas
107
How does POU domains interact with DNA?
Can be both positive and negative regulators of transcription and have alt splice variants. Specific domain and HD give DNA binding specificity and bund DNA as 2 separate domains. Helix 3 binds to the DNA often at A/T rich regions and octomer sequences (8 bases). The POU specific domain is thought to be involved in protein-protein interactions so probably binds to DNA dimers.
108
PIT1 gene disease and expression
In humans: CPHD Mouse: dwarfism Expressed in the pituitary glands Pit1 is required for specification of 3/5 cell types in the anterior pituitary gland
109
Expression of SKN1A
Skin
110
Disease of BRN4 and place of expression
Dfn3 deafness - X linked | Expression in the neural tube
111
Brn3c disease and expression
DFNA15 deafness autosomal expressed in the auditory system
112
Oct4 expression
ES cells and oocytes
113
RPF1 disease and expression
Wilms tumour - rare germline mutations | Expressed in various places
114
PIT1 stimulants what hormones in the pituitary gland and what happens on loss?
Prolactin and thyroid stimulatory hormone | Without development does not occur properly
115
Describe transition from a pre-implantation embryo to differentiation in terms of hox/oct expression
Pre implant embryo: oct4++, hoxa5- | Differentiation: oct4-, hoxa5 ++
116
How does oct4 affect hoxa5
Direct regulation by binding an octomer sequence in hoxa5. Oct4 is important in maintaining pleuripotentcy and is expressed in the female germline until gastrulation And is restricted to primordial germ cells by E8.5. High levels of oct4 seems to prevent differentiation into any cell type
117
What are sox genes?
High mobility group. This superfamily bind DNA specifically wth TCF and MATA
118
Developmental gene example of a zinc finger
Kruppel Drosophila is a gap gene that regulates pair-rule genes. Mutations in Kruppul lead to developmental problems
119
What is Gli3?
A zinc finger gene at the end of sonic hedgehog signalling pathway which is important in development Mouse: extra toes mutant Human: Grieg syndrome - skeletal malformations of hands feet and cranium (fuses early preventing proper brain dev)
120
Wt1 as a zinc finger gene
Deletion in WAGR syndrome. Human: WAGR and drash Wt1 is important in genutounrinary tract development
121
Pou genes are:
Regulators of development expressed in early embryogenesis and during forebrain development. Critical transactivators POU genes are expressed in distinct spatiotemporal patterns in the forebrain an area that does not express classic HD genes
122
3 POU genes and organism of discovery
Pit1 - rat Oct1/2 - human Unc86 - nematode
123
All POU genes have what?
A POU homeodomain (60aas) and a POU specific domain (DNA binding domain 74-82aas) separated by a spacer of 15-27aas
124
How does POU domains interact with DNA?
Can be both positive and negative regulators of transcription and have alt splice variants. Specific domain and HD give DNA binding specificity and bund DNA as 2 separate domains. Helix 3 binds to the DNA often at A/T rich regions and octomer sequences (8 bases). The POU specific domain is thought to be involved in protein-protein interactions so probably binds to DNA dimers.
125
PIT1 gene disease and expression
In humans: CPHD Mouse: dwarfism Expressed in the pituitary glands Pit1 is required for specification of 3/5 cell types in the anterior pituitary gland
126
Expression of SKN1A
Skin
127
Disease of BRN4 and place of expression
Dfn3 deafness - X linked | Expression in the neural tube
128
Brn3c disease and expression
DFNA15 deafness autosomal expressed in the auditory system
129
Oct4 expression
ES cells and oocytes
130
RPF1 disease and expression
Wilms tumour - rare germline mutations | Expressed in various places
131
PIT1 stimulants what hormones in the pituitary gland and what happens on loss?
Prolactin and thyroid stimulatory hormone | Without development does not occur properly
132
Describe transition from a pre-implantation embryo to differentiation in terms of hox/oct expression
Pre implant embryo: oct4++, hoxa5- | Differentiation: oct4-, hoxa5 ++
133
How does oct4 affect hoxa5
Direct regulation by binding an octomer sequence in hoxa5. Oct4 is important in maintaining pleuripotentcy and is expressed in the female germline until gastrulation And is restricted to primordial germ cells by E8.5. High levels of oct4 seems to prevent differentiation into any cell type
134
What are sox genes?
High mobility group. This superfamily bind DNA specifically wth TCF and MATA
135
What do all sox genes contain?
A SRY box which is a 79aa DNA binding domain and induces a bend in the DNA. They do this to open the DNA so other TFs can access it.
136
Characteristics of sox genes?
Highly conserved SRY box encoded by a single exon Non clustered DNA binding to AT rich regions. Sox genes bind to the minor groove in the DNA and bend it at an angleZ SoxA-H are activators excluding SoxB2 which is a repressor and soxD subgroup which lacks a transactivation domain (interrupted by retrovirus insertion)
137
What three things do sox genes interact with?
Interact with: DNA binding proteins to stabilise DNA binding and activate/repress transcription. And adaptor proteins to regulate sox activity (increase specificity to target gene). And nuclear import proteins
138
How does sox proteins make contact with other TFs?
Via an HMG domain which can also bind DNA
139
What do sox2 and pax6 do together?
Activate δ crystalline expression during lens induction
140
Where is SRY expressed?
Sertoli cells in developing tested
141
How was SRY the first sox end identified?
Cloning by identifying Y sequences in XX males - in gametogenesis translocation of Y material onto X chromosome SRY is on the Y chromosome of all males.
142
What mice is SRY absent in and what is the result?
In Tdy mice, get XY females
143
What does exctopic expression of sox9 induce?
Testes development
144
What reduces Sry expression in mice?
Mice lacking the +KTS form of WT1 suggesting that sry expression is perhaps due to +KTS being invoked in RNA metabolism
145
In transgenic sry females you get?
XX males although not with 100% efficiency
146
What is sry relationship with sox9?
Sry activates sox9. Sox9 is maintained by fgf9 in XX gonad primordia. Wnt4 ensures ovary development by suppressing fgf9. Mice lacking fgf9 experience XY sex reversal. In XY cells it would seem sry upregulates sox9 establishing an inductive loop between sox9 and fgf9 locking in the male determination pathway
147
What do all sox genes contain?
A SRY box which is a 79aa DNA binding domain and induces a bend in the DNA. They do this to open the DNA so other TFs can access it.
148
Characteristics of sox genes?
Highly conserved SRY box encoded by a single exon Non clustered DNA binding to AT rich regions. Sox genes bind to the minor groove in the DNA and bend it at an angleZ SoxA-H are activators excluding SoxB2 which is a repressor and soxD subgroup which lacks a transactivation domain (interrupted by retrovirus insertion)
149
What three things do sox genes interact with?
Interact with: DNA binding proteins to stabilise DNA binding and activate/repress transcription. And adaptor proteins to regulate sox activity (increase specificity to target gene). And nuclear import proteins
150
How does sox proteins make contact with other TFs?
Via an HMG domain which can also bind DNA
151
What do sox2 and pax6 do together?
Activate δ crystalline expression during lens induction
152
Where is SRY expressed?
Sertoli cells in developing tested
153
How was SRY the first sox end identified?
Cloning by identifying Y sequences in XX males - in gametogenesis translocation of Y material onto X chromosome SRY is on the Y chromosome of all males.
154
What mice is SRY absent in and what is the result?
In Tdy mice, get XY females
155
What does exctopic expression of sox9 induce?
Testes development
156
What reduces Sry expression in mice?
Mice lacking the +KTS form of WT1 suggesting that sry expression is perhaps due to +KTS being invoked in RNA metabolism
157
In transgenic sry females you get?
XX males although not with 100% efficiency
158
What is sry relationship with sox9?
Sry activates sox9. Sox9 is maintained by fgf9 in XX gonad primordia. Wnt4 ensures ovary development by suppressing fgf9. Mice lacking fgf9 experience XY sex reversal. In XY cells it would seem sry upregulates sox9 establishing an inductive loop between sox9 and fgf9 locking in the male determination pathway
159
In sry transgene in XX mice how efficient is maleness?
30%
160
What are the two types of chromosomal abnormality?
Numerical - euploidy, aneuploidy | Structural - translocations, chromosome rearrangements, deletions, duplications etc
161
What is diandry and digyny
Diandry is triploidy due to dispermy or diploid sperm so extra set of paternal chromosome Diagyry is triploidy due to diploid ovum or non-expulsion of polar body so extra set of material chromosomes
162
What is a pre implantation lethal aneuploidy?
Nullisomy (2n-2)
163
What trisomies survive?
13,18,21
164
How is trisomy 21 detected and diagnosed?
Detected cytogenetically and diagnosed by chorionic villus samples or by detecting fetal blood in maternal circulation
165
What does monosomy or trisomy arise from?
Non disjunction in meiosis I or meiosis II
166
Tetrasomy and pentasomy arise from?
Nondisjunction during meiosis I and meiosis II
167
What effect does maternal age have on trisomy rate?
Frequency of trisomies increases exponentially as maternal age increases
168
Learn table on page 19
About incidence of aneuploidy
169
What effect does maternal age have on trisomy rate?
Frequency of trisomies increases exponentially as maternal age increases. However this involves chronically ageing and not biological ageing
170
What is a strategy for trisomy correction?
Down's syndrome patient fibroblast. Trisomy 21 iPSC + Zinc finger targeting vector and xist with an inducible promoter + doxycyclin which activates xist on extra C21 to create a C21 Barr body
171
What is a Barr body?
Heterochromatin covering a chromosome
172
Anuploidy live born and syndrome:
XO - Turners, short, webbing around neck, cardio and renal problems XXY/XXYY - Kleinfelters, infertile and mental retardation XYY (XXX) - Jacobs most subtle abnormalities
173
In cri-du-chat syndrome what is the most important gene that is lost?
TERT on C5 involved in telomere length maintenance
174
What does deletion of sonic hedgehog on chromosome 7q lead to?
Holoprosenceohaly
175
What are the main unbalanced chromosome rearrangements
``` Micro deletions, Duplications, Dicentric chromosome (two centromeres) Ring chromosomes (telomere loss) Paracentric and peri centric rearrangements ```
176
Paracentric chromosome rearrangement is | Pericentric chromosome rearrangement is
Para: In one arm of the chromosome, doesn't involved the centromere Peri: involves centromere so rearrangement in each arm If the rearrangement is in frame it is unlikely to affect the carrier. More likely to affect children during crossing over
177
What is trisomy 21?
Down's syndrome - 15 fold increase In Leukaemia
178
What is patau syndrome
Trisomy 13
179
What is Edwards syndrome?
Trisomy 18
180
What is a strategy for trisomy correction shown by Jiang et al 2013
Down's syndrome patient fibroblast. Trisomy 21 iPSC + Zinc finger nuclease targeting vector and xist with an inducible promoter to the DYRK1A Locus with a transgene carrying dox control component rtTA into the AAVS1 gene on chr19 + doxycyclin which activates xist on extra C21 to create a C21 Barr body the edited C21 was enriched in all HC marks examined including H3K27me3, UBH2A and H4K20me. Xist induction on C21 showed repression of the APP gene. In vitro when more than one copy of c21 carried xist there was lack/loss of xist localisation after 20days showing there is selection and epigenetic adaption to circumvent a functional monosomy or nulisomy.
181
What is a Barr body?
Heterochromatin covering a chromosome
182
Anuploidy live born and syndrome:
XO - Turners, short, webbing around neck, cardio and renal problems XXY/XXYY - Kleinfelters, infertile and mental retardation XYY (XXX) - Jacobs most subtle abnormalities
183
In cri-du-chat syndrome what is the most important gene that is lost?
TERT on C5 involved in telomere length maintenance
184
What does deletion of sonic hedgehog on chromosome 7q lead to?
Holoprosenceohaly
185
What are the main unbalanced chromosome rearrangements
``` Micro deletions, Duplications, Dicentric chromosome (two centromeres) Ring chromosomes (telomere loss) Paracentric and peri centric rearrangements ```
186
How in paracentric rearrangement crossing over what causes gametes to be unviable?
Two centromeres or no centromeres the loss/ gain of genes does not make the chromosome unviable
187
Pericentric rearrangements causes what in crossing over?
Loss of certain genes and duplication of another
188
What is a common pericentric inversion?
Inv(3)(p25q21) Leads to facial abnormalities, cleft palate and mental retardation. Often need to look at parents to see how imbalance arises
189
Two types of translocation?
Robertsonian and reciprocal
190
How can reciprocal translocations be viewed?
FISH
191
How often is UPD observed with chromosomal abnormalities?
30%
192
What can complete chromosome UPD arise from?
Gamete complementation, triatomic rescue, monosomic rescue, mitotic error in connection with robersonian translocation, isochromosome formation, deletion and duplication
193
What can segmental UPD arise from?
Post zygote X somatic recombination between maternal and paternal homologue a or in connection with numeric and or structural chromosomal aberrations
194
What is heterodisomy?
Inheriting both chromosomes from 1 parental pair. On fusion with sperm - trisomy so loss of paternal chromosome. Due to error in meiosis I
195
What is isodisomy?
Inheriting
196
Pathogenic UPD includes:
Recessive diseases where parent is a carrier ie UPD7 - cystic fibrosis and UPD15 Bloom syndrome Maternal or paternal UPD of chromosome 15 gives prader willi syndrome or angleman syndrome (imprinting syndromes) UPD11p15.5 BWS
197
UPD can have what type of karyotypes? (5)
1. Have proven/suggested normal karyotype 2. Abnormal balanced karyotype 3. Abnormal unbalanced karyotype (with small supernumerary chromosomes or no sSMC) 4. Cases with segmental UPD 5. Often due to Robertsonian translocation
198
What is sSMC?
A 47th extra little chromosome - can be a ring chromosome or a double minute Can be a marker Only really makes a difference in isodisomy
199
Pathogenic UPD includes:
Recessive diseases where parent is a carrier ie UPD7 - cystic fibrosis and UPD15 Bloom syndrome Maternal or paternal UPD of chromosome 15 gives prader willi syndrome or angleman syndrome (imprinting syndromes) UPD11p15.5 BWS
200
UPD can have what type of karyotypes? (5)
1. Have proven/suggested normal karyotype 2. Abnormal balanced karyotype 3. Abnormal unbalanced karyotype (with small supernumerary chromosomes or no sSMC) 4. Cases with segmental UPD 5. Often due to Robertsonian translocation
201
What is sSMC?
A 47th extra little chromosome - can be a ring chromosome or a double minute Can be a marker Only really makes a difference in isodisomy
202
On silencing of C21 what pathology is reversed?
Deficits in proliferation and neural rosette formation are rapidly reversed
203
Difference in time between male and female meiosis
In Male meiosis begins with puberty and cells in the male testis progress from metaphase I to metaphase II without delay. Each cell that enters meiosis produces 4 sperm In the female. All oocytes initiated meiosis during fetal development but after homologous chromosomes undergo synopsis and initiate recombination. The oocyte enters a period of mitotic arrest. Resumption of meiosis and completion of the first division occurs years later in the ovary of a sexually mature woman just before ovulation. After completion of MI the oocyte arrests at metaphase of MII and normally the second division is completed only after fertilisation. Each cell that enters meiosis gives one egg and ⅔ polar bodies
204
How many fertilised human eggs have the wrong number of chromes and how does this differ from mice?
10-30% majority being monsomy or trisomy and with anueploidy accounting for ⅓ of spont abortions In mice does not exceed 1-2%
205
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
205
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
207
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
208
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
209
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
210
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
211
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
212
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
213
Three types of non disjunction
1 true non disjunction (homologues travel together to the same pole) 2 achiasmate non disjunction (where homologues fail to pair and independently travel to the same pole) 3 premature separation of sister chromatids
214
What trisomies do paternal errors account for?
50% of 47, XXYs and trisomy 2 but only 5-10% of most other trisomies
215
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
216
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
217
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
218
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
219
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
220
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
221
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
222
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
223
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
224
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
225
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
226
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
227
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
228
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
229
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
230
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
231
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
232
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
233
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
234
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
235
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
236
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
237
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
238
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
239
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
240
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
241
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
242
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
243
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
244
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
245
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
246
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
247
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
248
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
249
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
250
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
251
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
252
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
253
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
254
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
255
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
256
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
257
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
258
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
259
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
260
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
261
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
262
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
263
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
264
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
265
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
266
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
267
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
268
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
269
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
270
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
271
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
272
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
273
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
274
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
275
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
276
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
277
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
278
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
279
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
280
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
281
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
282
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
283
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
284
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
285
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
286
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
287
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
288
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
289
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
290
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
291
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
292
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
293
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
294
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
295
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
296
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
297
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
298
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
299
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
300
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
301
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
302
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
303
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
304
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
305
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
306
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
307
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
308
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
309
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
310
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
311
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
312
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
313
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
314
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
315
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
316
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
317
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
318
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
319
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
320
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
321
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
322
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
323
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
324
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
325
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
326
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
327
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
328
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
329
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
330
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
331
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
332
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
333
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
334
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
335
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
336
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
337
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
338
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
339
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
340
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
341
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
342
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
343
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
344
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
345
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
346
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
347
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
348
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
349
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
350
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
351
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
352
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
353
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
354
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
355
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
356
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
357
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
358
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
359
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
360
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
361
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
362
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
363
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
364
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
365
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
366
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
367
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
368
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
369
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
370
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
371
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
372
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
373
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
374
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
375
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
376
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
377
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
378
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
379
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
380
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
381
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
382
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
383
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
384
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
385
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
386
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
387
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
388
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
389
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
390
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
391
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
392
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
393
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
394
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
395
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
396
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
397
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
398
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
399
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
400
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
401
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
402
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
403
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
404
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
405
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
406
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
407
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
408
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
409
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
410
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
411
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
412
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
413
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
414
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
415
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
416
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
417
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
418
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
419
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
420
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
421
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
422
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
423
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
424
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
425
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
426
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
427
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
428
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
429
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
430
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
431
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
432
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
433
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
434
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
435
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
436
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
437
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
438
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
439
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
440
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
441
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
442
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
443
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
444
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
445
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
446
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
447
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
448
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
449
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
450
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
451
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
452
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
453
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
454
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
455
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
456
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
457
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
458
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
459
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
460
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
461
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
462
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
463
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
464
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
465
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
466
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
467
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
468
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
469
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
470
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
471
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
472
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
473
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
474
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
475
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
476
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
477
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
478
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
479
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
480
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
481
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
482
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
483
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
484
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
485
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
486
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
487
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
488
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
489
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
490
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
491
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
492
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
493
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
494
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
495
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
496
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
497
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
498
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
499
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
500
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
501
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
502
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
503
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
504
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
505
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
506
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
507
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
508
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
509
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
510
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
511
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
512
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
513
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
514
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
515
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
516
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
517
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
518
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
519
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
520
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
521
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
522
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
523
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
524
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
525
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
526
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
527
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
528
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
529
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
530
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
531
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
532
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
533
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
534
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
535
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
536
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
537
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
538
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
539
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
540
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
541
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
542
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
543
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
544
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
545
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
546
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
547
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
548
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
549
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
550
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
551
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
552
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
553
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
554
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
555
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
556
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
557
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
558
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
559
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
560
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
561
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
562
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
563
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
564
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
565
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
566
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
567
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
568
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
569
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
570
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
571
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
572
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation 677C>T. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al 1999 showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls. Since this data was published 15 years on there has been lots of conflicting reports but the evidence is that folate metabolism has only a weak independent maternal risk for having a child with DS. There is arguments that due to MI beginning in embryogenesis he maternal grandmothers folate intake may provide risk.
573
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
574
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls.
575
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
576
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls.
577
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
578
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls.
579
What associations other than maternal age are associated with trisomies?
None, many have been implicated but they have not been verified
580
What genetics is there contrasting evidence over link to Down syndrome? This is a long answer
MTHFR point mutation. Protein involved in Folate metabolism and cellular methylation reactions. James et al suggested that the point mutation leads to abberant methylation and may increase likelihood of meiotic non-disjunction. Also MTRR polymorphisms protein involved in folate pathway and liked to increase in spins bifida. James et al showed that mothers with Down syndrome children had a higher proportion of heterozygous (MTHFR) and mutant homozygotes (both). However this is only in relation to trisomy 21 folate metabolism doesn't affect non disjunction in any other chromosome trisomy. And the evidence for 21 is disputed as Peterson et al were unable to demonstrate any increase in MTHFR mutations compared with controls.
581
What recombination effects are there that contribute to trisomies?
Reductions in recombination are a feature of all MI- derived trisomies Achiasmatic homologues also reduces recombination Distal chiasma and recombination seems to be a risk factor of trisomy 21

DG & EC (6 decks)

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