Genetics

Question 1

List the clinical features of tuberose sclerosis

Answer 1

Epilepsy, seizures
Periungual fibromata
Longitudinal ridging
Ash-leaf macule

Question 2

Tuberose sclerosis is autosomal recessive. True/False?

Answer 2

False

Autosomal dominant

Question 3

What is meant by non-penetrance?

Answer 3

Having the mutation but not having features of the disease

Question 4

In autosomal dominance, what is the % risk of affected child if a parent is affected?

Answer 4

50%

Question 5

Which genes become mutated to cause tuberose sclerosis?

Answer 5

TSC1
TSC2
N.B. only either 1 or 2 becomes mutated

Question 6

Which inhibitors partially correct tuberose sclerosis?

Answer 6

mTOR inhibitors

Question 7

Tuberose sclerosis is a common disorder. True/False?

Answer 7

False

It is a high penetrance Mendelian disorder (so not common)

Question 8

What is epidermolysis bullosa?

Answer 8

A group of genetic skin fragility conditions involving blistering and erosion

Question 9

Simplex EB affects ?Junctional EB affects ?Dystrophic EB affects ?

Answer 9

Simplex EB affects epidermis
Junctional EB affects DEJ
Dystrophic EB affects dermis

Question 10

What is meant by haploinsufficiency disease?

Answer 10

One gene can’t produce the protein, so you end up with less protein overall

Question 11

What is the most common genetic dermatological condition? What inheritance pattern does it have?

Answer 11

Neurofibromatosis type 1

Autosomal dominant

Question 12

How does a mutated NF1 gene cause neurofibromatosis?

Answer 12

NF1 is responsible for switching off cell cycle

Mutated NF1 therefore promotes excessive cell proliferation

Question 13

List clinical features of neurofibromatosis

Answer 13

Café-au-lait macules
Neurofibromas
Axillary/inguinal freckling
Lisch nodules

Question 14

What is the protein mutated in atopic eczema? What does it affect?

Answer 14

Filagrin

Skin barrier function due to lack of keratohyalin granules