Genetics

Question 1

Most common chromosomal defect type in down’s

Answer 1

Non disjunction in 94%
Robertsonian translocation in 5%
Mosaicism in1%

Question 2

genetics of Haemochromatosis

Answer 2

auto recessive

Question 3

Rule about autosomal dominant Vs recessive

Answer 3

Autosomal recessive conditions are ‘metabolic’ - exceptions: inherited ataxias are ‘structural’ but recessive

Autosomal dominant conditions are ‘structural’ - exceptions: Gilbert’s, hyperlipidaemia type II

Question 4

Genetics of Peutz-Jeghers syndrome

Answer 4

Auto dominant.

numerous hamartomatous polyps in the GI tract, with pigmented freckles on the lips, face, palms and soles..

.50% of patients will have died from another GI cancer by the age of 60 years

Question 5

Genetics and features of myotonic dystrophy

Answer 5

Dystrophia myotonica -DM1

distal weakness initially
autosomaldominant
diabetes
dysarthria

Can have cateracts

Question 6

Genetics of haemochromatosis

Answer 6

Autosomal recessive disorder of iron absorption / metabolism

HFE gene chromosome 6

Question 7

Prognosis with Philadelphia translocation t(9;22)

Answer 7

GOOD in CML

BAD in AML + ALL

Question 8

Molecular biology techniques blot plotting….

Answer 8

SNOW DROP
South NOrth West -ern blotting techniques
DNA RNA Protein

Question 9

DiGeorge Syndrome mnemonic

Answer 9

It has a variable presentation however its features can be remembered with the mnemonic CATCH22:

C -Cardiac abnormalities

A - Abnormal facies

T - Thymic aplasia
Tetany hypocal due to paraThyroid
T-cell deficiency due to Thymus

C -Cleft palate

H -Hypocalcaemia/ hypoparathyroidism

22 - Caused by chromosome 22 deletion

Question 10

What diagnosis for following translocations

11;14
8;14 
9;22 
14;18
15,17

Answer 10

11;14 -> 11 looks like a M -> Mantle
8;14 -> 8 looks like B -> Burkitt
9;22 -> 9 looks like flipped P -> Philadelphia
14;18 -> 4licular/ follicular lymphoma
15,17 -> well it’s none of the above :D -> it’s the long name Acute Promyelocytic Leukemia.

Question 11

Polycystic kidney disease type 1 and 2 chromosomes

Answer 11

16 and 4

Question 12

Homocysteinuria Vs cysteinuria

Answer 12

Both auto recessive
Homocyst isa disorder in metabolism of methionine,an amino acid, causing vitamin b12, b6 , folate deficiency

Cysteinuria is too much cysteine (amino acid) in urine, kidney stones

Question 13

Genetics of congenital nephrogenic diabetes insipidus

Answer 13

X-linked mutation in the vasopressin (ADH) receptor gene (the more common form)

Autosomal recessive defect in the aquaporin 2 gene (the less common form)

Question 14

Genetics of Marfan’s

Answer 14

FBN1 gene on chromosome 15 that codes for the protein fibrillin-1

Question 15

HLA association with coeliac

Answer 15

I ate (8) too (2) much gluten at Dairy Queen - for Celiac Disease DQ8/DQ2

Question 16

HLA association with rheumatoid arthritis

Answer 16

There are 4 walls in a ‘rheum’ (room) - for Rheumatoid A. HLA DR4

This is also asssx with T1DM, and less so DR3

Question 17

HLA association for multiple sclerosis

Answer 17

Multiple Hay Pastures have DiRT - Multiple sclerosis, Hay fever, Goodpasture synd. for HLA DR2

Question 18

genetics of achondroplasia

Answer 18

70-80% is from sporadic/spontaneous mutation, but following this it tends to be autosomal dominant

Question 19

X-linked Dominant conditions

Answer 19

Alports (in 85%, the rest auto R, very rare auto D)
Rett Syndrome
Vit D resistant Rickets

Question 20

will children of man with Alports have the condition?

Answer 20

X-linked Dom

So sons wont have it, daughters will

Question 21

inheritance of mitochondrial disease

Answer 21

all children of male will NOT inherit
all children of female will inherit.

although poor genotype:phenotype correlation
muscle biopsy may show red ragged fibres (due to increased mitochon)

Question 22

most common cardiac abnormality in Down’s

Answer 22

Endocardial cushion defect (AKA Atrioventricular septal canal defect)

Question 23

Which LQT syndrome is associated with deafness?

Answer 23

Jowel and Lange-Nielson syndrome has profound deafness

RomaNO ward = NO deafness

Question 24

ATP7B is the dysfunctional protein associated with…

Answer 24

… Wilson’s disease.

Question 25

Which deficiency is associated with haemochromatosis?

Answer 25

HFE

Question 26

JAK-STAT is the mutation associated with…

Answer 26

primary polycythaemia ruba vera

Question 27

Glucuronyl transferase deficiency causes…

Answer 27

Gilbert disease

Question 28

What chromosome is mutation on ADPKD 1?

Answer 28

polycystic kidney … 16 letters… chromosome 16 (ADPKD type 1)

Sixteen/cysteen?

Question 29

Chromosomes re neurofibromatosis 1 and 2

Answer 29

NF1: chromosome 17 - as neurofibromatosis has 17 characters

NF2: chromosome 22 - all the 2’s (2x schwannomas

Question 30

Genetics of Edwards syndrome

Answer 30

Trisomy 18

Question 31

What mutation cause Marfan’s

Answer 31

mutation in a protein called Fibrillin-1

marFans - Fibrillin

Question 32

Genetics of familial hypercholesterolemia

Answer 32

Auto dom

Mostly heterozygous
Homozygous die in teenage years

Question 33

HLA associated with T1DM

Answer 33

HLA DR4

And to less extent DR3

Question 34

What is mutation in gitelman

Answer 34

NaCl symporter

Normotensive

Question 35

Mutation in barters

Answer 35

Na-K-Cl cotransporter

Normotension + Hypokalaemia = Gitelman’s & Bartter’s

Question 36

Mutation in Liddel

Answer 36

Hypertensive hypokal

Na channels in DCT

Question 37

HLA bronchiectasis

Answer 37

DR1