Genetics in Dermatology

Question 1

widespread blistering and loss of skin in a newborn that is worsening?

Answer 1

epidermolysis bullosa

Question 2

how many generations are affected in autosomal dominant inheritance?

Answer 2

all

Question 3

what happens in the dominant-negative disease mechanism

Answer 3

abnormal protein stops normal protein working

Question 4

what is the risk of an infected child if the parent is affected in autosomal dominant inheritance?

Answer 4

50%

Question 5

clinical signs of neurofibromatosis type 1?

Answer 5

cafe au lait macules
neurofibromas
freckling of axilla/groin
optic glioma

Question 6

what is the result of haploinsufficiency?

Answer 6

get half as much functioning protein

Question 7

how many generations affected in autosomal recessive inheritance

Answer 7

often only 1

Question 8

2 types of ridging commonly seen in the nails

Answer 8

longitudinal

transverse

Question 9

what happens to a protein encoded by autosomal recessive genes?

Answer 9

no protein produced

Question 10

3 main types of epidermolysis bullosa?

Answer 10

simplex (in epi)
junctional (DEJ)
dystrophic (dermis)

Question 11

what do TSC1 and 2 genes normally code for?

Answer 11

TSC1 = Hamartin
TSC2= Tuberin

Question 12

what characteristics does a mendelian disorder have?

Answer 12

rare but very penetrable so you will get a strong phenotype

Question 13

where do the mutations occur in tuberous sclerosis?

Answer 13

TSC1 and TSC2

Question 14

what is haploinsufficiency?

Answer 14

only 1 gene working rather than 2

Question 15

what aspect of the faulty tuberous sclerosis pathway can be inhibited to treat the disease?

Answer 15

inhibiting mTOR gene

Question 16

what form of inheritance does tuberous sclerosis take

Answer 16

autosomal dominant

Question 17

what is a hamartoma?

Answer 17

overgrowth of normal tissue

Question 18

is TS mendelian or common?

Answer 18

mendelian

Question 19

systemic symptoms of tuberous sclerosis

Answer 19

facial angiofibromas
seizures/epilepsy
hamartomas
bone cysts
enamel pitting
shagreen patches (++ connective tissue)

Question 20

common cytokines that play a big part in atopic eczema?

Answer 20

IL-4, IL-13

Question 21

what happens when filaggrin is mutated?

Answer 21

ichthyosis vulgaris (fish scales), atopic disease risk +++

Question 22

how many de novo mutations do children have?

Answer 22

120 mutations

Question 23

common nail presentation of tuberous sclerosis

Answer 23

periungual fibromas and longitudinal ridging of nails

Question 24

what are ash leaf macules and what condition are they common in?

Answer 24

depigmented macules on body

Question 25

what causes epidermolysis bullosa?

Answer 25

acquired autoimmune condition affecting over 10 genes involved in skin structure and adhesion

Question 26

what is a genodermatosis?

Answer 26

inherited skin condition

Question 27

% risk of child getting the disease if it’s autosomal recessive?

Answer 27

25%

Question 28

what is the driving force behind mendelian disorders?

Answer 28

mutations

Question 29

what is the driving force behind common disorders?

Answer 29

SNPs
CNVs
Mutations