Genetics

Question 1

Which genes are associated with early onset Alzheimer’s?

Answer 1

PSEN-1
PSEN-2
APP
ApoE

Question 2

Which genes are associated with late onset Alzheimer’s?

Answer 2

ApoE

Individuals with two ApoE4 alleles are 15 times more likely to develop dementia and people with one ApoE4 allele are three times more likely to develop dementia

Question 3

Which genes are associated with familial frontotemporal dementia?

Answer 3

C9orf72

MAPT

Question 4

Which genes are associated with Huntington’s disease?

Answer 4

IT15 (huntingtin)

Question 5

Which gene is associated with CADASIL (cerebral autosomal dominant arteriography with subcortical infarcts and leukoencephalopathy)?

Answer 5

Notch3

Question 6

What is the inheritance pattern of neurofibromatosis (types 1 and 2)?

Answer 6

Autosomal dominant

Question 7

What is the inheritance pattern of Huntington’s disease?

Answer 7

Autosomal dominant

Caused by CAG repeats

Question 8

What is the inheritance pattern of achondroplasia?

Answer 8

Autosomal dominant

Question 9

What is the inheritance pattern of noonans syndrome?

Answer 9

Autosomal dominant

Question 10

What is the inheritance pattern of phenylketonuria?

Answer 10

Autosomal recessive

Question 11

What is the inheritance pattern of hurlers syndrome?

Answer 11

Autosomal recessive

Question 12

What is the inheritance pattern of Tay-Sachs disease?

Answer 12

Autosomal recessive

Question 13

What is the inheritance pattern of friedreichs ataxia?

Answer 13

Autosomal recessive - caused by GAA repeats

Question 14

What is the inheritance pattern of Wilson’s disease?

Answer 14

Autosomal recessive

Question 15

What is the inheritance pattern of vitamin D resistant rickets?

Answer 15

X-linked dominant

Question 16

What is the inheritance pattern of cerebellum ataxia?

Answer 16

X-linked recessive

Question 17

What is the inheritance pattern of Hunters syndrome?

Answer 17

X-linked recessive

Question 18

Which is the inheritance of fragile X syndrome?

Answer 18

Sex-linked - caused by CGG triplet repeats

Fragile X syndrome causes mental impairment (inherited) and is a common cause of autistic like behaviour.

Question 19

What is the inheritance pattern of Lesch-Nyhan syndrome?

Answer 19

Sex-linked

LNS is a rare disorder that causes a build up of uric acid in the body causing gout, poor muscle control and moderate retardation. Also associated with self-mutiliating behaviour such as lip and finger biting.

Question 20

What is epistasis?

Answer 20

The interaction of genes that are not alleles - two or more loci work together to create a new phenotype.

Question 21

What is pleiotropy?

Answer 21

Describes how a single gene causes multiple phenotypic traits.

Question 22

Which receptor gene is associated with variability in weight gain when being treated with anti-psychotics?

Answer 22

5-HT2c

Question 23

What is the chromosomal genotype of Klinefelter’s syndrome?

Answer 23

47XXY

Symptoms include:
Infertility (almost universal)
Low testosterone levels
Gynaecomastia
Small testes
Poorly developed secondary sexual characteristics
Can also have a mild intellectual disability however IQ may be normal