Genetics Flashcards
1
Q
DNA composition:
A
Double helix, nitrogen bases with deoxyribose-phosphate backbone
A- adenosine
C-cytosine
G-guanine
T-Thymine
2
Q
RNA composition:
A
Single strand, nitrogen bases with ribose-phosphate backbone
A- adenine
C-cytosine
G- guanine
U- uracil
3
Q
How is messenger RNA formed?
A
DNA transcribed–>
Primary mRNA–>
Splicing (introns removed)–>
Mature mRNA
4
Q
What was ribosomal RNA do?
A
Part of the ribosome
Binds mRNA and tRNA to the ribosome
5
Q
What does transfer RNA do?
A
Transports amino acids
Translates mature mRNA
Anticodon (at 3’ end) binds complementary mRNA codon
6
Q
What is transcription?
A
Synthesis of an mRNA sequence from a DNA template
7
Q
What is DNA polymerase?
A
Enzyme that utilizes complementary DNA strand as a template to create a new strand
8
Q
What is RNA polymerase?
A
Enzyme that binds a promoter region to synthesize mRNA from the DNA template
9
Q
What is reverse transcriptase?
A
Enzyme that transcribes RNA into DNA
10
Q
A telomere is
A
The distal end of a chromosome that maintains integrity and stability
11
Q
Mature mRNA is made from
A
Primary mRNA transcribed from DNA
12
Q
The DNA segment between exons that is spliced out in mature mRNA
A
Intron
13
Q
The DNA sequence transcribed to mature mRNA for ultimate gene material is
A
Exon
14
Q
DNA transcription starts at
A
Promotor
15
Q
Assembly of amino acids from mRNA and tRNA to protein is called
A
Translation
16
Q
Identification of a DNA sequence by amplification then isolation of a specific sequence is
A
PCR
17
Q
Southern analysis is
A
DNA identification with electrophoresis
18
Q
Northern analysis is
A
Electrophoresis to identify RNA
19
Q
Western analysis is
A
Electrophoresis to identify protein
20
Q
FISH works by
A
Fluorescent tagging of a complementary DNA sequence with exposure to fluorescent light to identify presence or absence of that sequence
21
Q
Ordered attachment of DNA molecular fragments to a slide is
A
Microarray
Can determine number of copies, over-/under- expression, or mutations in a gene
22
Q
The most common malformations in the US are
A
Neural tube defects
23
Q
Most malformations are due to
A
Unknown causes (70%)
24
Q
Genetic causes of malformations are ___%
A
20%
25
Environmental causes ___% of malformations
10%
26
A mutation that results in a codon change to a stop codons is a
Nonsense mutation
27
A mutation that results in changing from one codon to another is
Missense mutation
28
A splice site mutation causes
Retained intron in mRNA, changing translation
29
A reciprocal translocation is
A break in 2 chromosomes with exchanged material, normal phenotype
30
A Robertsonian translocation is
Fusion of long chromosome arms with lost material from short arms
Normal phenotype until subsequent generations
31
X linked recessive inheritance pattern is
50% transmissible from female carrier as carrier to female offspring or as disease to male offspring
Universally transmitted carrier status to female offspring from male carrier with no transmission to male offspring
Potential abnormal phenotype in female carrier
32
X linked dominant inheritance pattern is
2x common in females
50% transmission to both male and female offspring from affected female
Universally transmitted disease to female offspring from male carrier with no transmission to male offspring
33
Common autosomal recessive disorders:
```
21-hydroxylase deficiency
Cong muscular dystrophy
Cystic fibrosis
IEM (most)
Sickle cell
Thalassemia
```
34
Hematologic autosomal dominant diseases
Protein C and S deficiency
Spherocytosis
Gilbert
vWD
35
Neurologic autosomal dominant diseases
Congenital myotonic dystrophy
| Neurofibromatosis
36
Genetic autosomal dominant diseases
```
Apert
Crouzon
Holt-Oram
Marfan
Noonan
Stickler
Treacher-Collins
```
37
Derm autosomal dominant diseases
```
Aplasia cutis
Bullous ichthyosis
Ichthyosis vulgaris
Epidermolysis bullosa simplex
Keratosis pilaris
Partial albinism
Peutz-Jegher
Waardenburg
```
38
Renal autosomal dominant diseases
Adult PCKD
39
GI autosomal dominant diseases
Familial polyposis
Gardner
Alagille
40
Ophtho autosomal dominant diseases
Retinoblastoma
41
Ortho autosomal dominant diseases
Achondroplasia
Postaxial polydactyly
Osteogenesis imperfecta
Thanataphoric dysplasia
42
X-linked recessive metabolic disease
Fabry
Hunter
Menkes
Ornithine carbamyl transferase
43
X-linked recessive hematologic disease
G6PD
Wiskott-Aldrich
Hemophilia A and B
44
X-linked recessive neurologic disease
Color blindness
| Duchene muscular dystrophy
45
X-linked recessive derm disease
Hypohidrotic ectodermal dysplasia
| X-linked ichthyosis
46
X-linked recessive renal disease
Nephrogenic DI
47
Genomic imprinting is
Phenotypic variation based on maternal or paternal inheritance
Imprinting= silencing/deletion of that parent's gene
48
Uniparental disomy is
Inheritance of both copies of a given gene from one parent
49
Trinicleotide repeat expansion
Increase phenotypic severity with each generations due to increased CTG repeat numbers
50
Recurrence risk of CHD
3%
51
Recurrence risk of cleft lip/palate
5-10%
52
Recurrence risk of hip dysplasia
3%
53
Recurrence risk of club foot
4%
54
Recurrence risk of Hirschsprung
4%
55
Recurrence risk of NTD
4%
56
Recurrence risk of pyloric stenosis
3% to subsequent sibling
Maternal inheritance: 19% in son, 7% in daughter
Paternal inheritance: 5% in son, 3% in daughter
57
Recurrence risk of Tri21
1% sibling risk in affected parents
5-10% with parental balanced translocation
58
Campylodactyly, thick lips, deep eyes, cupped ears with fetal demise in non-mosaic fetuses is
Trisomy 8
59
Cutis aplasia, midline defects, hyperconvex fingernails, clefts, and holoprosencephaly describes
Trisomy 13
60
___% of infants trisomy 13 sure within the first year
90%
95% of all cases result in SAB
61
VSD, clenched hands, rocker bottom feet, micrognathia, small mouth, female>male is
Trisomy 18
62
Prognosis of trisomy 18 is
95% SAB
| 90% death in the first year
63
Cri du chat is inherited _______ and presents with
Paternal, short arm 5th chromosome partial deletion
```
VSD
hypertelorism
Cat like cry
Microcephaly
Hypotonia
FTT
```
64
Retinoblastoma, thumb hypoplasia, colobomas, microcephaly, cryptorchidism and SGA are consistent with
Deletion 13q
65
A maternal deletion of 15q11-13 with paternal uniparental disomy causes
Angelman syndrome
66
Presentation of Angelman syndrome is
Inappropriate laughter, large mouth, maxillary hypoplasia, puppet-like movement and gait, severe developmental delays with absent speech
67
Velocardiofacial syndrome is also _____ which is caused by _____
DiGeorge, autosomal dominant/de novo
| 22q11.2 deletion
68
DiGeorge presentation is noted by CATCH 22:
```
Cardiac
Abnormal facies
Thymic hypoplasia
Cleft
Hypocalcemia
```
4th brachial arch and 3/4th pharyngeal pouch defects
69
A deletion or methylation of 15q11-13 of paternal origin, maternal parental disomy results in
Prader-Willi
70
Rubenstein -Taybi syndrome is due to
Microdeletion of 16p13.3
| Hypoplastic maxilla
71
WAGR represents
Wilms Tumor
Aniridia
GU abnormalities
Retardation
11p13 deletion
72
______ syndrome caused by 7q11.23 deletion presents with
Williams
```
Supravalvular subaortic stenosis
Hypoplastic nails
Prominent lips
Stellate iris
Mental deficiency
```
73
A mutation in the transmembrane domain of the fibroblast growth factor receptor 3 gene causes
Achondroplasia (4p16.3)
| Autosomal dominant
74
Crouzon and Apert syndromes are both caused by
Autosomal dominant inheritance of mutation in fibroblast growth factor receptor 2 gene.
75
Unlike Apert syndrome, Crouzon presents with
```
Maxillary hypoplasia (not midface)
Frontal bossing
Premature mixed craniosynostosis
Hearing and visual deficits
Normal mental function
```
76
Risk of ________ malignancy in Beckwith-Wiedemann is ___% and is inherited _____
Wilms Tumor/hepatoblastoma
5-10%
Autosomal dominant, 11p15.5
77
ASD, absent or abnormal thumbs, and hypertelorism are consistent with
Holt -Oram syndrome
| Autosomal dominant
78
An abnormal fibrin gene, inherited ______, causes ______
Autosomal dominant
| Marfan syndrome
79
In contrast to Turner, Noonan is inherited ______ and has ___________ (signs).
Autosomal dominant
```
Dysplastic pulmonary valve
Cryptorchidism
Abnormal coagulation
Increased von willebrands
Cystic hygromas
```
80
The most mild form of osteogenesis imperfecta is
Type 4
Normal sclera
+/- abnormal dentition
81
The most severe type of osteogenesis imperfecta is ______ and causes
Type 2
Blue sclera
Short, broad bones
Stillbirth or early death
82
Osteogenesis imperfecta associated with easy bruising is type _____ and also has
Type 1
8-25% fractures at birth or in first year
Deafness
Wormian bones
83
Fractures present at birth is usually osteogenesis imperfecta ______ which also has:
Type 3
```
Blue sclera
Macrocephaly
Deafness
Kyphoscoliosis
Short stature
```
84
Osteogenesis imperfecta is inherited
Autosomal dominant,
Type 1 collagen defect
85
A type 2 collagen defect with autosomal dominant inheritance
Stickler syndrome
86
Myopia, spondyloepiphyseal dysplasia and flat facies are consistent with
Stickler syndrome
87
A mutation in the extracellular or intracellular tyrosine kinase domain of fibroblast growth factor receptor 3 gene is
Thanataphoric dysplasia
| 4p16.3
88
TCOF gene mutation causing 1/2nd branchial arch maldevelopment causes
Treacher-collins
| 'mandibulofacial dysostosis'
89
Coloboma, mandibular hypoplasia, malar hypoplasia, hearing and visual deficits and hypoplastic zygomatic arch are
Treacher-Collins
90
Pigmentary abnormalities that can include deafness, Hirschsprung,
Waardenburg
| Autosomal dominant, PAX3 or microphthalmia gene
91
Carpenter syndrome is ____ inheritance and has
Autosomal recessive
PDA, VSD
polydactyly
Dysmorphic facies
Brachycephaly
92
CHD in Ellis van Creveld is
Single atrium/ASD
93
Hyperpigmentation, radial and thumb hypoplasia, pancytopenia with increased risk of AML is
Fanconi pancytopenia syndrome
| 35% mortality
94
An autosomal recessive syndrome with ASD, polydactyly, occipital encephalocele and cystic dysplastic kidneys is
Meckel-Gruber
95
An autosomal recessive defect in cholesterol synthesis that causes increased 7-dehydrocholesterol is
Smith Lemli Opitz
96
Features of Smith Lemli Opitz include
Genital hypoplasia (under virilization)
Syndactyly
Mental deficiency
High mortality
97
Thrombocytopenia, absent radii and ulnar abnormalities is inherited _______ and has _____(CHD) and ____% mortality
Autosomal recessive
TOF
40% mortality from hemorrhage
98
CDH and Dandy Walker is
Fryns syndrome
| Autosomal recessive
99
Inheritance of fragile X syndrome is
X-linked dominant with variable penetrance-
80% in males
30% in females
CGG repeats
100
Presentation of fragile X is
```
Long facies
Prominent forehead
Large ears
Large testes
Mental deficiency
Hyperextensibility
Autism
```
101
Kinky hair syndrome is
Menkes syndrome
X-linked recessive
Abnormal copper transport, inability to act as cofactor for enzymes
102
Infants who die early in infancy following twisted, lightly pigmented hair, cerebral deterioration, seizures, and wormian bones is
Menkes syndrome
103
Presentation of mitral valve prolapse, hypogonadism, gynecomastia, long limbs, behaviorism concerns is concerning for
Klinefelter
| 47 XXY
104
An infant with bicuspid aortic valve, CoA, cystic hygroma, webbed neck, gonadal dysgenesis, horseshoe kidney, short stature and broad chest likely has
Turner syndrome
| 45, XO
105
Outcome of most pregnancies with a fetus with Turner's is
Spontaneous abortion (98%)
106
22q11 quadruplicate or triplicate results in
Cat eye syndrome
107
Major features of cat eye syndrome are
TAPVR
```
down slanting eyes
Anal atresia
Coloboma
Mental deficiency
Renal agenesis
```
108
Genetic cause of 6th and 7th nerve palsy is
Mobius sequence
109
Neurological defects in Mobius sequence can include ______. _______ _______ ________ and are associated with _____ and ______ syndromes
Brain nuclei destruction
Brain nuclei hypoplasia/absence
Peripheral nerve involvement
Myopathy
Poland and Klippel-Feil syndromes
110
An expressionless face, micrognathia, extensive cranial nerve dysfunction and limb deformities are consistent with
Mobius sequence
111
Micrognathia secondary to mandibular hypoplasia with hearing loss is
Pierre-Robin sequence
112
Pierre-Robin sequence can be associated with
Trisomy 18
Stickler syndrome
Treacher-collins
FAS
113
CHARGE association is
```
Coloboma
Heart disease (TOF, DORV)
Atresia of choana
Restricted growth
Genital hypoplasia
Ear anomalies
```
Mental deficiency common (94%)
114
Micromelia, synophrys, thin down turned lip, long curly eyelashes, hypertonicity, microbrachycephaly, hirsutism, VSD suggests
Cornelius de Lange
115
Oculo-auriculo-vertebral or facio-auriculo-vertebral spectrum is also known as ______ and inherited
Goldenhar syndrome- 1st/2nd branch abnormalities
Sporadic
116
Goldenhar syndrome presents with
```
Malformed ears, pits or tags
Hemivertebrae/hypoplasia
Facial hypoplasia
VSD
Unilateral pattern
```
117
A sprengel deformity is part of
Klippel-Feil syndrome
- abnormal elevation and medial rotation of the scapula
118
A webbed neck with a short neck, low hairline, fused cervical vertebrae and deafness is
Klippel-Feil
119
Asymmetric limb hypertrophy with vascular lesions is
Klippel-Trenaunay-Weber
120
Proximal subclavian artery disruption causes
Poland sequence:
Poorly developed ipsilateral distal limb/pectoral region
Syndactyly
Male>>
75% RIGHT
121
Small triangular facies, asymmetric skeleton, and a small incurved 5th finger is
Russell-Silver syndrome
| Maternal uniparental disomy
122
VACTERL is
```
>3 of:
Vertebral anomalies
Anal atresia
Cardiac (VSD)
TEF
Renal anomaly
Limb dysplasia
```
Increased in IDM
