Genetics

Question 1

Karyotype for Turners

Answer 1

XO

Question 2

Karyotype for Edwards Syndrome

Answer 2

Trisomy 18

Question 3

Karyotype for Klinefelter syndrome

Answer 3

XXY

Question 4

Genetic defect in Noonan’s syndrome

Answer 4

Defect in the Ras/MAPK signaling pathway

Question 5

Genetic Inheritance of Huntington’s Disease

Answer 5

Autosomal Dominant
CAG triplet repeats on chromosome 4
Index cases can occur due to a de novo mutation or due to anticipation

Question 6

Kleinfelter hormone findings + clinical manifestations

Answer 6

High FSH and LH, low testosterone

Small penis and balls
Risk of DM, CVD, cancer

Question 7

In what clinical situation is the CGH microarray most useful for?

Answer 7

Chromosomal microdeletion

Question 8

What is the mechanism of somatic chromosomal translocation in causing cancer?

Answer 8

Gene fusion

Question 9

Duchenne MD gene mutation

Answer 9

Multi exon deletion

X chromosome linked

Question 10

Tuberous sclerosis

Answer 10

Low intelligence
Epilepsy
Adenine sebacium

Autosomal dominant

Question 11

DiGeorge

Answer 11

CATCH22 
Chromosome 22 deletion 
Cardiac defect tetralogy fallout
Abnormal facies 
Thymic aplastic with infections
Cleft palates
Hypocalcaemia

Question 12

Purines

Answer 12

Adenine
Guarnine
2 ring structure

Question 13

Pyramidines

Answer 13

Cytosine
Uracil (RNA)
Thymine (DNA)
Single ring structure

Question 14

What happens during G2 phase of the cell cycle

Answer 14

Cell is preparing for mitosis

Microtubule productin

Question 15

What happens during G1 phase of the cell cycle

Answer 15

The cell grows and synthesid of mRNA and proteins including histones. The volume of the cytoplasm is increased

Question 16

What happens during S phase of the cell cycle

Answer 16

DNA synthesis

Chromosome duplication

Question 17

What does telemorase ribonucleoprotein do?

Answer 17

Adds base pairs to DNA to cap the DNA

Question 18

interfering mRNAs (micro-RNAs) action

Answer 18

mRNA degradation

Question 19

Missense mutation

Answer 19

A substitution in one DNA base pair that changes the codon for one amino acid to the codon for another amino acid

Question 20

Nonsense mutation

Answer 20

A substituation of a DNA base that changes a codon to a stop codon

Question 21

Splice site mutation

Answer 21

Intron or exon exon deletion

Question 22

frameshift mutation

Answer 22

deletion of 1 nucleotide within 1 exon

Question 23

Mutation seen in Duchenne muscular dystrophy

Answer 23

Deletion of multiple exons (splicing)

Question 24

PARP-1 action

Answer 24

required for base excision repair (BER)

Question 25

Mechanism of somatic chromosomal translocation in causing cancer?

Answer 25

Gene fusion

Question 26

Examples of alleilic heterogeneity

Answer 26

Same gene location Different allele mutations Same Disease CF MEN

Question 27

Examples of Locus (non-allelic) heterogeneity

Answer 27

Different genes Same Disease ``` BRCA-1/2 HOCM Familial hypercholesterolaemia Ehndler-Danlos Retinitis Pigmentosum ```

Question 28

Transmission of mitochondrial mutation

Answer 28

Heteroplasmy with mitochondrial inheritence (from mother with all children affected)

Question 29

Barr body

Answer 29

Inactivated X chromosome due to lyonisation

Question 30

Pleiotropy

Answer 30

One mutation affecting multiple organs | e.g. CTFR in CF

Question 31

Epistasis

Answer 31

One gene impacts on the expression of others | e.g. albinism

Question 32

Gene mutation in Fragile X

Answer 32

CGG repeats leading to silencing of FMR-1 gene | X-linked dominant pattern

Question 33

Features of fragile X

Answer 33

``` Long narrow face Large ears prominent jaw Enlarged testicles Mental retardation ```

Question 34

Genetics of prader-willi syndrome

Answer 34

Disruption or deletion of genes in chromosome 15

Question 35

Clinical features of prader willi-syndrome

Answer 35

``` Small statue Small hands and feet Central obesity Intellectual disability Characteristic behaviours ```

Question 36

Type of mutation leading to a proto-oncogene

Answer 36

Missense

Question 37

Tays-Sachs mutation

Answer 37

Frameshift muation

Question 38

In frame deletion

Answer 38

Deletion of 3 base pairs

Question 39

Linkage disequilibrium

Answer 39

Non-random associations between polymorphisms at different loci

Question 40

Marfan's gene

Answer 40

FBN-1 gene

Question 41

Noonan's syndrome clinical

Answer 41

``` Autosomal dominant Short stature Variable intellectual disability Pulmonary stenosis (also HOCM, ASD, VSD) ```

Question 42

Treatment of AF in HOCM

Answer 42

Anticoagulate (warfarin) despite CHADVASC

Question 43

When to avoid stress ECG/Echo

Answer 43

LBBB

Question 44

Heart block in which atropine should not be used

Answer 44

Mobitz type 2

Question 45

Fabry disease

Answer 45

``` GL-3 ubiquitous accumulation X Linked recessive GI symptoms Kidney failure Cardiac hypertrophy, arrhythmia, valvulopathy Peripheral neuropathy Stroke ```

Question 46

Still's disease

Answer 46

``` Fever Arthralgia Salmon-rash LN Organomegaly ```

Question 47

Li-Fraumeni Disease

Answer 47

Autosomal dominant p53 suppressor gene mutation Cancers at ~25yo sarcomas, breast, leukaemia

Question 48

Peutz jager disease

Answer 48

``` Autosomal dominant STK11 gene Harmatomous polyps GIT Pigmented macules (lips) Risk of Ca GIT, pancreas, breast, ovary ```

Question 49

Neurofibromatosis 1

Answer 49

Autosomal dominant NF-1 gene for neurofibromin ``` Cafe-aut-lait spots Lisch nodules Cognitive impairment Neurofibromas Bony lesion ```

Question 50

Neurofibromatosis 2

Answer 50

bilateral acoustic schwannomas and meningiomas No lisch nodules Schwannomas Less cognitive impairment

Question 51

Tuberous Sclerosis

Answer 51

Autosomal dominat TSC1 - hamartic TSC2 - tuberin Skin - hypopigmented lesion, angiofibromas, shagreen patched Tumours- brain, heart (rhabdomyoma), skin, eyes, kidney (angiomyolipomas), lung, and liver.

Question 52

Charcot-Marie-Toot disease

Answer 52

Autosomal dominal PMP-22 gene coding for myelin Peripheral motor and sensory neruopathy

Question 53

Myotonic dystrophy

Answer 53

Autosomal dominant T1: DMPL genge Type 2: CNBP gene ``` Myotonia Characteristic facies - hatchet facies Fatigue Cataracts Cardaic abnormalities ```

Question 54

Tay-Sachs disease

Answer 54

Autosomal recessive Lysosomal storage disorder - HEXA gene Neurodegenerative disorder, children die at 4

Question 55

Duchenne/Becker Muscular dystropy

Answer 55

X Linked Recessive Dystrophin gene Intellectual disability Heart failure Muscle and respiratory weakness

Question 56

Freidrich's ataxia

Answer 56

``` Autosomal recessive Mitochondrial dysfunction (GAA triplet repeat) ``` Ataxia HOCM Diabetes

Question 57

Alport syndrome

Answer 57

X Linked dominant Type 4 collagen - ears, lens, kidney issues

Question 58

Rett syndrome

Answer 58

X Linked Dominant- MECP2 Affects brain development in girls