Genetics

Question 1

Numerical

Answer 1

Aneuploidy /loss or gain chromosome

Question 2

Structural chromosome abnormalities

Answer 2

Translocations / deletions / insertions

Question 3

Mosaicism

Answer 3

Mutations in embryo not in sex cell

Present in 60% spontaneous misscarriages

Question 4

Aneuploidy

Answer 4

Numerical abnormality in loss/gain chromosome

Question 5

Monosomy

Answer 5

Loss of single chromosome (halves protein)

Question 6

Trisomy

Answer 6

Gain of one chromosome

Downs syndrome (21)
Edwards (18)
Pataus (13)

33%increase protein

Question 7

Tetrasomy

Answer 7

Gain of two chromosomes

Tolerated

Question 8

Robertsonian translocation

Answer 8

Only have Q arm

Acrocentric

Question 9

Cause of Downs Syndrome

Answer 9

90%maternal origin

Non disjunction in meiosis 1 (75%)

Non disjunction in meiosis 2 (25%)

Question 10

Chromosomal microdeletion disorder

Answer 10

Prader willi syndrome

Deletion of paternal chromosome 15q11-13

Question 11

Mutation

Answer 11

Heritable change in DNA sequence

Causes monogenic diseases

Question 12

Polymorphisms

Answer 12

> 1% frequency in each population

Contribute towards complex diseases

Question 13

Missense mutation

Answer 13

Incorrect replacement of AA

Question 14

Nonsense mutation

Answer 14

Incorrect sequencing

Question 15

Insertion mutation

Answer 15

Insertion of Single nucleotide which equates to an incorrect amino acid sequence

Question 16

Deletion mutation

Answer 16

Malfunctioning protein formed

Question 17

Huntingtons disease

Answer 17

Autosomal dominant

Vertical transmission

HTT gene affected

27 to >35 glutamine repeats

Question 18

Genetic anticipation

Answer 18

Age of onset of disease decreases and severity increases

Question 19

Cystic fibrosis

Answer 19

Autosomal recessive

Delta F508 mutation

Question 20

X-linked recessive

Answer 20

Haemophillia

Males affected not females

Question 21

Haemophillia A

Answer 21

F8 —> coagulation factor VIII

Occurs on chromosome X

Question 22

Haemophillia B

Answer 22

F9 mutation —> coagulation IX

Occurs on X chromosome

Question 23

Penetrance

Answer 23

Frequency with which symptoms are present

Question 24

Variable expressivity

Answer 24

Degree of severity

Question 25

Phenocopy

Answer 25

Same disease /different underlying cause Prader Willi /Obesity

Question 26

Epistasis

Answer 26

Interaction between gene mutations and other modifier genes which affect phenotype

Question 27

Dominant

Answer 27

Gene mutations that results in toxic protein

Question 28

Recessive

Answer 28

Caused by absence of working protein

Question 29

Multifactorial disease

Answer 29

Diabetes Mellitus Genetics / environment

Question 30

SNP

Answer 30

1 in every 1000 base pairs >3.2 million different SNPs between unrelated people Affect health/ appearance

Question 31

TCF7L2

Answer 31

SNP increases risk of T2D

Question 32

Germline mutation

Answer 32

Mutation occurs in the egg/sperm Genes affect are DNA repair/regulation BRACA1 /BRACA2

Question 33

Somatic mutation

Answer 33

Mutations occurring in body cells

Question 34

Chronic Myelogenous leukaemia

Answer 34

TKinase always active Cells divide uncontrollably

Question 35

Pharmacogenetics

Answer 35

Difference between individuals in response to drugs