Genetics

Question 1

Precision medicine is most effective for common/rare diseases and high/low penetrance mutations

Answer 1

Rare diseases

High penetrance mutations

Question 2

What is meant by a non-penetrant mutation?

Answer 2

When an individual carries the gene for a disease but are unaffected/so mildly affected that they are asymptomatic

Question 3

Define polymorphism

Answer 3

Genetic variation that has no pathogenic effect

Question 4

What is the risk of an affected parent having an affected child in…
- autosomal dominant
- autosomal recessive
…inheritance?

Answer 4

Dominant -> 50% risk

Recessive -> 25% risk

Question 5

Give an example of a dermatological disease caused by a high penetrance mutation

Answer 5

Tuberous sclerosis

Question 6

Describe haploinsufficiency mutations

Answer 6

Only one copy of the gene is mutated, therefore only one copy is working and so there is reduced protein production

Question 7

Describe dominant negative mutations

Answer 7

Expression of an abnormal protein interferes with the normal protein function
(important for oncogenes)

Question 8

Describe gain of function mutations

Answer 8

The mutant protein gains a new function which affects cell processes

Question 9

Describe complete loss of function mutations

Answer 9

Autosomal recessive mutation results in 2 faulty copies of the gene and so no protein is produced

Question 10

Eczema is a multifactorial disease. True/False

Answer 10

True

Question 11

Which mutation is important in the development of eczema?

Answer 11

Mutations in the filaggrin gene

Question 12

What type of mutation is most common in the filaggrin gene?

• haploinsufficiency
• dominant negative
• gain of function
• loss of function

Answer 12

Loss of function (~1 in 10)

Question 13

The risk of eczema has a normal/left skewed/right skewed distribution of risk

Answer 13

Normal