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part I > genetics > Flashcards

genetics Flashcards

1
Q

how many pairs of chromosomes does a human have?

structure

A

23

short arm (p) & long arm (q)
joined at centromere

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2
Q

what is a chromosome called when:
i) arms are same length
ii) one arm is longer than other
iii) centromere is situated at top of chromosome

A

i) metacentric
ii) submetacentric
iii) acrocentric

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3
Q

name given to:
i) 1st 22 pairs of chromosomes
ii) 23 pair of chromosomes

A

i) autosomes
ii) sex chromosomes

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4
Q

what is a gene?

How many genes are there in human genome?

A

a specific sequence of DNA that carries the instructions for the construction of a protein

approx 20,000

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5
Q

what is meiosis?

what are the 2 division cycles in meiosis called?

A

division of germ cells to produce ova or sperm

meiosis I
meiosis II

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6
Q

what happens during meiosis I?

A
  1. chromosomes duplicate
  2. recombination = homologous chromosomes align and reciprocal exchange of genetic material occurs between homologous but nonidentical chromatids
  3. diploid number of chromosomes is reduced to half number
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7
Q

what happens during meiosis II?

A

splitting of sister chromatids

(like mitosis but no additional replication)

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8
Q

in female meiosis how many of the 4 daughter cells survive?

A

only 1
(all 4 survive in male meiosisis)

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9
Q

what is aneuploidy?

A

abnormality in number of chromosomes i.e. chromosomes are not haploid

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10
Q

what happens in non-disjunction?

what increases risk of non-discjunction?

A

pairs of homologous chromosomes at **meiosis I **or sister chromatids during mitosis anaphase do not separate so both chromosomes are passed onto 1 daughter cell

therefore:
- 1 daughter cell has 3 chromosomes (trisomy)
- 1 daughter cell is missing 1 chromosome (monosomy)

advanced maternal age

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11
Q

examples of non-disjunction:

A

Down Sydrome (trisomy 21)

Edward’s syndrome (trisomy 18)

Patau syndrome (trisomy 13)

^^ order above = most to least common trisomies

Klinefelter Syndrome (47, XXY)

Turner syndrome (45,X) - most common monosomy identified at birth

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12
Q

Down syndrome
i. mutation

ii.clinical features

A

nondisjunction in 95% (other causes include Robertsonian translocation)

characteristic facial features -upslanting palpebral fissures, epicanthic folds, flat midface, brachycephaly (short anterior-posterior diameter of cranium)

moderate- severe learning difficulties (100%)

cardiac problems (40-50%, VSD, ASD, AVSD)

dementia (10-15%)

ALL

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13
Q

Edward’s syndrome

i. which chromosome is affected
ii. what’s the issue
iii. clinical features

A

poor prenatal/ postnatal outcomes
i. trisomy 18

ii.
meiotic dysjunction
unbalanced Robertsonian translocations (less common)

iii.
survival - usually <1 year

Profound learning difficulties (100%)
Congenital heart disease (90%, commonly VSD)
Facial clefts
Spina bifida
Clenched hands
Rocker-bottom feet

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14
Q

Patau syndrome

i. chromosome affected
ii. genetic cause
iii. clinical features

A

i. trisomy 13

ii. 90% nondysjunction of chromosome 13 (majority of these during maternal meiosis - rest = due to unbalanced translocations (primarily Robertsonian translocations)

iii.
highest rate of spontaneous pregnancy loss of all the trisomies

Profound learning difficulties (100%)
Holoprosencephaly (60–70%) = when brain doesn’t separate into 2 hemispheres properly
Scalp defects
Cleft lip/palate (60–70%)
Microphthalmia/anophthalmia (60–70%)

Congenital heart disease (80%, VSD, ASD)

Postaxial polydactyly (60–70%)

Omphalocele
Renal anomalies

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15
Q

Klinefelter syndrome
i. affected genes
ii. clinical features

A

i. additional sex chromosome 47 XXY

ii. Slightly decreased IQ but within the normal range
Tall stature
feminine fat distribution
small testes
Infertility
Transient gynaecomastia

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16
Q

Klinefelter dx:

A

not usually dx unless incidental finding during:
prenatally
during chorionic villus sampling (CVS) or amniocentesis or in adulthood during infertility investigations

does not cause increase nuchal translucency so not ID on scan

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17
Q

i. hormonal changes in Klinefelter’s:

ii. incidence of Klinefelters

A

hormonal imbalances

FSH, LH ^^
estradiol ^^
SHBG^^ (sex hormone binding globulin)

testosterone vv

ii. 1 in 650 males

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18
Q

triple X syndrome clinical features:

A

Slightly decreased IQ but within the normal range
Tall stature
Normal fertility

usual only found incidentally

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19
Q

XYY syndrome clincial features:

A

Slightly decreased IQ (within the normal range)
Tall stature after puberty
Behavioural problems

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20
Q

Turner syndrome

i. common antenatal feature which prevents survival to term

ii. which finding on USS would make you consider this as dx

iii. clinical features

A

45,X

i. usually do not survive to term due to hydrops fetalis

ii. nuchal translucency >4mm

iii. primary amenorrhoea, delayed puberty

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21
Q

Turner syndrome

i. clinical features

ii. rx:
- to promote puberty
- to prevent osteoporosis

A

i. amenorrhoea (may have spontaneous menstruation due to mosaicism)
delayed puberty
short stature
webbing of neck
cubitus valgus (angling out of forearm at elbow)
widely spaced nipples
cardiac abnormalities (most commonly bicuspid aortic valve)
renal abnormalities

most common cause of gonadal dysgenesis

ii. - low dose ostrogen to promote puberty
- LT hormone replacement to prevent osteoporosis

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22
Q

what are reciprocal translocations?

A

Chromosome rearrangements involving the transfer of genetic material between two nonhomologous chromosomes

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23
Q

most common translocation in humans

A

t(11; 22)(q 23; q 11)

involves chromosome 11 and 22

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24
Q

what happens in Robertsonian translocation?

A

chromosome rearrangement that involves fusion of the long arms of two acrocentric chromosomes and loss of their short arms.

The genes contained on the short arms are represented elsewhere and so their loss does not result in any phenotypic effect of acrocentric chromosomes.

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25
Q

which 5 chromosomes can Robertsonian translocation affect?

A

only the acrocentric ones!!

13, 14, 15, 21, 22

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26
Q

most common Robertsonian translocations (2)

A

rob (13q; 14q)
involves fusion of chromosome 13 to chromosome 14

rob(14q; 21q)
involves fusion of chromosome 14 to chromosome 21

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27
Q

what is impriting?

(in context of Robertsonian translocation)

which 2 chromosomes are imprinted genes found on?

A

process by which one parental allele is preferentially silenced according to its parental origin.

14 & 15

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28
Q

what is UPD?

which chromosomes can it affect?

A

uni-parental disomy …. p 277

again only in with chromosome 14 & 15

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29
Q

outcome & clinical features of
i. maternal UPD 14
ii. paternal UPD 14

A

i. survive to term
–> small, learning difficulties, hypotonia, relative marocephaly

ii. spontaneous miscarriage
–> (if survive to term) profound LD, feeding diffiuclties, joint contractures

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30
Q

outcome of:
i. paternal UPD15
ii. maternal UPD 15

A

i. Angelman syndrome
ii. Prader-Willi syndrome

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31
Q

Angelman syndrome
i. cause
ii. clinical features

A

i. paternal UPD 15

ii. severe learning difficulties
characteristic facial
appearance
ataxic gait

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32
Q

Prader-Willi syndrome
i. cause
ii. clinical features

A

i. maternal UPD 15
ii. severe learning difficulties
poor feeders in neonatal period, then insatiable appetite and overweight
hypotonic
short stature

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33
Q

what are chromosomal microdeletions?

how are these usually picked up?

A

chromosomal deletions that are too small to be detected by light microscopy using conventional cytogenetic methods

microarray aCGH

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34
Q

common microdeletion syndromes:

A

5p15 (cri du chat)

7q11 (Williams)

22q11 (DiGeorge)

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35
Q

Cri du chat
i. mutation
ii. clinical features

A

5p15 deletion

Severe learning difficulties
Characteristic cat-like cry
Characteristic facial appearance with bitemporal narrowing, hypertelorism (wide distance between eyes)
and downslanted palpebral fissures

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36
Q

Williams syndrome
i. mutation
ii. clinical features

A

7q11

Mild to severe learning difficulties
Cardiac problems, particularly supravalvular aortic/pulmonary stenosis
Renal artery stenosis
Characteristic facial appearance with short upturned nose, long philtrum, wide mouth,
periorbital fullness
‘Cocktail party personality’ (chatty, interactive behaviour)

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37
Q

DiGeorge syndrome

i. mutation
ii. other names
iii. clinical features

A

22q11 deletion

velocardiofacial
Shprintzen

C- cardiac anomalies (most commonly tetralogy of Fallot, VSD, interrupted aortic arch)

A - abnormal facies
(tubular nose, narrow palpebral fissures
and simple ears)

T - t-immune cell disorder

C- cleft palate

H - hypocalcaemia

22 - variable deletion on chromosome 22

Mild to moderate learning difficulties

+
Short stature
Psychiatric disorders
Renal anomalies

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38
Q

what are missense mutations?

A

single-base substitutions that have occurred in a coding, critical region of the gene.

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39
Q

what is a frameshift mutation?

A

one or more bases
(but not a multiple of three) are inserted or deleted from
the usual genetic sequence so disrupting the normal
reading frame

eventually a new stop codon will be generated resulting in abnormal protein being prematurely truncated

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40
Q

what are nonsense mutations?

A

a single-base substitution that generates a premature stop codon resulting in a truncated protein

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41
Q

what do both nonsense and frameshift mutations produce?

what are they thus both collectively called?

A

truncated proteins

truncating mutations

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42
Q

what is splicing?

what are splice mutations?

A

removal of introns from primary transcript

mutations that affect nucleotides at the splice site (junction between introns and extrons)

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43
Q

what are exon deletions?

A

occur when 1 or more exons are deleted in a process that does not constitute an alternative splicing event

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44
Q

what causes triplet repeat expansions?

examples of triplet repeat conditions? (3)

important feature in these conditions? (3)

A

extensive duplication of a single codon. If this goes beyond a certain threshold you get an abnormal phenotype

fragile X syndrome
Huntingdon’s
mytonic dystrophies

  1. variability in phenotype
  2. anticipation (progression in triplet repeat size and phenotype severity as repeat is passed onto next generation)
  3. parent of origin effect (repeat may expand more if passed on by mother than father)
45
Q

4 patterns of inheritance for genes on single locus:

A

autosomal dominant
autosomal recessive
X-linked dominant
X-linked recessive

46
Q

common autosomal dominant conditions & their genes:

A

tuberous sclerosis (TSC 1/TSC2)
Marfans (fibrillin 1)
neurofibromatosis type 1 (NF 1)
breast/ ovarian cancer susceptibility (BRCA1/BRCA2)
HNPCC (MLH)
Huntington’s disease (Huntingdin)
autosomal dominant polycycstic kidney disease (PKD1/PKD2)
achondroplasia (FGFR3)

47
Q

tuberous sclerosis
i. affected gene
ii. inheritance
iii. clinical features
iv. which chromosome is mutation on

A

i. TSC1/TSC2
ii. AD
iii.Multisystem disorder characterised by:
- cutaneous (angiofibromata, hypomelanotic
macules, shagreen patches)
- neurological (brain hamartomas causing seizures)
- renal (angiomyolipomata)

should be strongly suspected prenatally if
cardiac rhabdomyosarcomas are identified
iv. chromosome 9 or 16

48
Q

Marfan syndrome
i. affected gene
ii. inheritance
iii. clinical features

A

i. fibrillin I
ii. AD (25% of cases are de novo i.e. not inheritted, v occassionally gene is also recessive?!)
iii.Tall stature, arm span to height ratio >1.05, long fingers, dolicocephaly, aortic
dilatation and other cardiac anomalies

49
Q

neurofibromatosis type I
i. affected gene
ii. inheritance
iii. clinical features

A

i. NF1
ii. AD
iii. Combination of cafe-au-lait ´ spots, neurofibromata, axillary and inguinal freckling and
optic glioma

50
Q

breast/ ovarian cancer susceptibility
i. affected gene
ii. inheritance
iii. clinical features

A

i. BRCA1/ BRCA2
ii. AD
iii.

BRCA1
60-90% breast ca
40-60% ovarian ca

BRCA2
45-80% breast ca
10-30% ovarian ca

51
Q

HNPCC
i. affected gene
ii. inheritance
iii. clinical features

A

i. MLH
ii. AD
iii. Inherited predisposition to the development of colon and other cancers including
endometrial, gastric and ovarian

52
Q

Huntingdon’s disease
i. affected gene
ii. inheritance
iii. clinical features

A

i. Huntingdin
ii. AD
iii. Condition characterised by progressive neurological deterioration with dementia,
psychiatric disturbance and movement disorder

53
Q

Autosomal dominant
polycystic kidney disease
i. affected gene
ii. inheritance
iii. clinical features

A

i. PKD1/ PKD2
ii. AD
iii. Systemic disorder with cysts in the kidneys, liver, pancreas and spleen and
cardiovascular anomalies including intracranial aneurysms and mitral valve prolapse

54
Q

achondroplasia
i. affected gene
ii. inheritance
iii. clinical features

A

i. FGFR3
ii. AD
iii. Condition characterised by disproportionate short stature with rhizomelic (proximal)
shortening and relative macrocephaly

55
Q

if 2 carriers of autosomal recessive gene have children what is the chance of:
i child being affected?
ii child being carrier

A

1 in 4
2 in 4

56
Q

common autosomal recessive conditions (& affected gene) :

A

cystic fibroisis (CFTR)
Spinal muscular atrophy (SMN)
Tay–Sachs disease (HEXA)
Haemochromatosis (HFE)
α1-Antitrypsin deficiency (SERPINA1)
Congenital adrenal hyperplasia due
to 21-hydroxylase deficiency (CYP21A2)

57
Q

cystic fibrosis
i. affected gene
ii. inheritance
iii. features

A

i. CFTR
ii. autosomal recessive

iii.chronic pulmonary disease exocrine pancreatic dysfunction
male infertility (absence of vas deferens)

58
Q

In Caucasian population:

i. what proportion is a CF carrier?

ii. what is the chance of a couple having a child with cystic fibrosis?

A

i. 1 in 20 to 1 in 25

ii. 1 in 400

59
Q

spinal muscular atrophy
i. affected gene
ii. inheritance
iii. features

A

i. SMN
ii. autosomal recessive
iii.Characterised by symmetrical proximal muscle weakness; life expectancy
ranges from infancy to adulthood depending upon the type of spinal muscular
atrophy

60
Q

Tay-Sachs disease
i. affected gene
ii. inheritance
iii. features

A

i. HEXA
ii. autosomal recessive
iii. A GM2 gangliosidosis characterised by a ‘cherry-red spot’ on the retina and
deteriorating motor and cognitive abilities

61
Q

haemachromatosis
i. affected gene
ii. inheritance
iii. features

A

i. HFE
ii. autosomal recessive
iii. Excess absorption of iron with deposition in liver, pancreas and skin leading
to cirrhosis, diabetes mellitus and bronzed appearance of skin

62
Q

α1-Antitrypsin deficiency
i. affected gene
ii. inheritance
iii. features

A

i. SERPINA1
ii. autosomal recessive
iii.1 α1-Antitrypsin is a proteinase inhibitor that protects the lungs from elastase;
without α1-antitrypsin individuals will develop emphysema at a young age; they
may also develop cirrhosis owing to a direct effect of the abnormal
α1-antitrypsin on the hepatocytes

63
Q

Congenital adrenal hyperplasia due
to 21-hydroxylase deficiency
i. affected gene
ii. inheritance
iii. features

A

i. CYP21A2
ii. autosomal recessive
iii. 2 Attributable to abrogation of 21-hydroxylase, required for the synthesis
of cortisol; associated with female virilisation and abnormal puberty (precocious
in boys) with or without salt wasting

64
Q

X linked recessive inheritance characteristics

A

if recessive mutation is on X chromosome males will be affected

  • only males are affected (if for some reasons females are affected they will have a milder phenotype
  • there is no male to male transmission
  • condition may appear to skip conditions
65
Q

examples of X-linked recessive conditions & affected gene:

A

Duchenne muscular (dystrophin)
Haemophilia A (factor VIII gene)
ocular albinism (GPR143)
X-linked adrenoleucodystrophy (ABCD1)
Fragile X Syndrome (FMR 1)

66
Q

Duchenne muscular dystrophy:
i. affected gene
ii. inheritance
iii. features

A

i. dystrophin
ii. X-linked recessive
iii. delayed motor development
Progressive myopathy affecting proximal muscles
causes early loss of ambulation and
death in the third decade owing to respiratory failure

pseudohypertrophy of calf muscels
waddling gait
cardiomyopathy (dilated)

67
Q

haemophilia A
i. affected gene
ii. inheritance
iii. features

A

i. factor VIII gene
ii. X-linked recessive
iii. Attributable to deficiency of factor VIII, an important component of the clotting cascade;
affected male individuals have abnormal clotting, with severe haemophilia A leading to
spontaneous joint and muscle bleeding

68
Q

occular albinism
i. affected gene
ii. inheritance
iii. features

A

i. GPR 143
ii. X-linked recessive
iii. Hypopigmentation of iris and retina; associated with poor visual acuity, nystagmus,
strabismus and abnormal decussation of the optic nerves

69
Q

X-linked adrenoleucodystrophy
i. affected gene
ii. inheritance
iii. features

A

i. ABCD 1
ii. X-linked recessive
iii. Accumulation of very-long-chain fatty acids in the adrenal glands and brain; results in
progressive cognitive deterioration and adrenal failure

70
Q

Fragile X syndrome
i. affected gene
ii. inheritance
iii. features

A

i. FMR 1
ii. X-linked recessive
iii.Caused by expansion of a CGG repeat; results in learning difficulties and characteristic
facial appearance

71
Q

X-linked dominant inheritance features:

A
  • manifests v v severely in male fetuses resulting in loss of pregnancy or early neonatal death

thus mainly in females

72
Q

X-linked dominant conditions & affected gene

A

Incontinentia pigmenti (NEMO)
Rett syndrome (MECP2)

73
Q

Incontinentia pigmenti
i. affected gene
ii. inheritance
iii. features

A

i. NEMO
ii. x-linked dominant
iii. Initially presents as blistering lesions following Blaschko lines; these later become
hyperpigmented and eventually appear as atrophic streaks

74
Q

Rett syndrome:
i. affected gene
ii. inheritance
iii. features

A

i. MECP 2
ii. x-linked recessive
iii. Associated with cognitive regression and severe learning difficulties; other characteristic features
include hand wringing and stereotypical movements

75
Q

examples of conditions displaying mitochondrial inheritance:

A

MELAS (mitochondrial encephelomyelopathy with lactic acidosis and stroke-like symptoms)
MERRF (myoclonic epilepsy with ragged red fibres)
Leigh’s disease Subacute necrotising encephelomyelopathy

76
Q

which 2 screening tests are routinely offered and at what gestation?

A
  1. nuchal translucency (11-14 weeks)
    = sonographic appearance of subcutaneous fluid at back of foetal neck
  2. amniocentesis (15-20 weeks)
77
Q

which maternal factor makes NIPT (non-invasive prenatal testing) less accurate?

A

maternal obesity - lowers % of free foetal DNA

78
Q

associations of thickened nuchal translucency?

A

Noonan’s
chromosomal trisomy
???p 283

79
Q

what is the combined test (in foetal abnormality screening)?

A

uses info from nuchal translucency scan + 2 serum biochemical markers:
PAPP-A
h β-hCG

80
Q

what is detection rate of trisomy by:
i. NT scanning alone
ii. combined testing

A
  1. 70-75% (false positive rate 5%)
  2. near 90%
81
Q

what are cffDNA tests?

what are they used for used for:

A

circulating free foetal DNA (free foetal DNA is released by apoptotic cells in the placenta - therefore its cells are representative of nuclear content of cells in developing foetus

determining sex
rhesus D blood typing

detection of trisomy 13, 18, 21

82
Q

chorionic villus sampling:

i. earliest gestation it’s performed at

ii. what are the 2 layers of the chorionic villus?

A

i. 11 weeks

ii. aspiration of placental tissue

chorionic villus has 2 cell layers:
outer = cytotrophoblast (rapidly dividing and invading layer)
inner= mesenchymal core

83
Q

how long does it take to get CVS results from
i. outer cytotrophoblastic layer
ii. inner mesenchymal core

which layer is seen as more representative?

A

i. 1-2 days
ii. 1-3 weeks

core (as outer layer is established earlier) - therefore if abnormal cytotrophoblastic result must wait for mesenchymal result)

84
Q

what is confined placental mosacisism?

what % CVS samples is this seen in?

A

where chromosomal abnormality is present in placenta but not foetal tissue

1.5%

85
Q

amniocentesis

i. gestation performed at

ii. which foetal organs are the amiocytes derrived from?

iii. how long after procedure are cultured cells from amiocentesis available to harvest?

A

i. after 15 weeks

ii. skin, urinary and GIT

iii. 1-3 weeks

86
Q

what are the miscarriage rate after CVS/ amniocentesis?

advantage of CVS>amniocentesis?

A

approx 1%

results more rapidly availably

87
Q

i. what is cordocentesis?

ii. from what gestation can this be done?

iii. associated miscarriage rates?

A

i. sampling of foetal from umbillical vein

ii. 18 weeks

iii. 1-2%

88
Q

what is cordocentesis used to asses?

A

anaemia
prenatal infection

89
Q

FISH (fluorescent in situ hybridisation)

i. uses
ii. advantages
iii. disdvantages

A

i. rapid aneuploidy detection
evaluation of unbalanced translocations

ii. A good technique for investigating
predictable unbalanced
chromosome rearrangement

iii. spenny
labour intensive

90
Q

QF-PCR (quantitatvie fluorescence PCR)
i. uses
ii. advantages
iii. disadvantages

A

i. rapid aneuploidy detection

ii. rapid results
cheap

iii. Will usually only identify abnormal
dosage involving chromosomes 13,
18 or 21

91
Q

MLPA (Multiplex ligation-dependent probe amplification)
i. uses
ii. advantages
iii. disadvantages

A

i. Rapid aneuploidy detection
Evaluation of unbalanced
translocations

ii. rapid results

iii. limited genomic coverage

92
Q

array-CGH (microarray comparatice genomic hybridisation)

i. uses
ii. advantages
iii. disdvantages

A

i. Rapid aneuploidy detection
Detection of microdeletions
Detection of microduplications

ii. rapid results
info re: gene dosage throughout genome

iii. New assay, so unclear whether
abnormal results are pathogenic
variants or polymorphisms

93
Q

lifetime risk of ovarian cancer in general population

A

1 in 70

94
Q

genes associated with breast ca development (6)

A

BRCA1 &BRCA2

MMR genes” MSH2, MLH1, MSH6, PMS2

95
Q

BRCA 1
i. lifetime risk of breast Ca
ii. lifetime risk of ovarian ca

A

i. 60-90% breast ca
ii. 40-60% ovarian ca

96
Q

BRCA 2
i. lifetime risk of breast ca
ii. lifetime risk of ovarian ca

A

i. 45-80%
ii. 10-30% ovarian Ca

97
Q

what’s the overall contribution of BRCA 1 and BRCA2 to breast ca (%)?

A

<2%

98
Q

what is the risk of ovarian ca in women with BRCA 1&2 who opt for prophylactic BSO?

what happens to the risk of breast ca?

A

1% (peritoneal)

halved

99
Q

which malignancies are MMR gene alterations most commonly associated with?

A

colorectal
endometrial
gastric
ovarian

100
Q

risk of endometrial cancer with MMR defects?

A

50%

101
Q

HNPCC risk of of:
i. ovarian cancer?
ii. endometrial cancer?

A

i. 4%
ii. 50%

102
Q

how are tumours tested for HNPCC?

A

immunohistochemistry

103
Q

syndromes associated with ovarian ca (3)

A

i. HNPCC = the artist formerly known as Lynch syndrome (MMR repair mutation)
ii. Peutz- Jegher syndrome
iii. Cowden disease

104
Q

Peutz- Jegher syndrome
i. what is the mutation?
ii. clinical features?
iii. what is the lifetime risk of GI malignancy
?
iv. what is the lifetime risk of endometrial cancer

A

i. mutations
within the gene encoding serine/threonine protein
kinase 11 (LKB1)
ii.pigmented macules
of the mucous membranes and skin, gastrointestinal
polyps
iii. 30%
iv. 40%

105
Q

aneuploidy risk evaluation

what 3 tests are done in 1st trimester?

A

nuchal translucency
nasal bone measurement
assessment of blood flow in ductus venosus

106
Q

in trisomy 21 what would you expect to happen to:

  1. nuchal translucency
  2. nasal bone measurement
  3. blood flow in ductus venosus
A
  1. increased
  2. absent/ hypoplastic nasal bone
  3. absent/ reversed a wave
107
Q

combined testing
1. which trimester is combined test done?

  1. what are the 3 parts?
  2. what would happen to result in down syndrome?
A
  1. 2nd trimester
  2. NT, bHCG, PAPP-A
  3. ^^ NT, ^^bHCG, vv PAPP-A
108
Q
  1. which semester is triple/ quadruple screen done in?
  2. what tests are in the triple screen?
  3. what tests are in the quadruple screen?

result for these if Down syndrome

A
  1. α-FP + ^^ β-hCG + vv unconjugated oestradiol
  2. as above + ^^inhibin

part I (12 decks)

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