Genetics

Question 1

a 35-year-old lady presented with these lesions on her hands and feet -

epilepsy age 7yrs
normal intelligence

Periungual fibromata (tumours around nails) & longitudinal ridging

diagnosis?

Answer 1

tuberous sclerosis

Question 2

tuberous sclerosis is one of the most common ____________

Answer 2

tuberous sclerosis is one of the most common GENODERMATOSES

Question 3

what may tuberous sclerosis present with in infants?

Answer 3

infantile seizures

Question 4

what is the earliest cutaneous sign in tuberous sclerosis?

Answer 4

ash-leaf macule

Question 5

tuberous sclerosis is autosomal ________

Answer 5

tuberous sclerosis is autosomal DOMINANT

Question 6

what are the facial tumours called in tuberous sclerosis and where are they most commonly found on the face?

Answer 6

facial angiofibromas

nasal labial folds

Question 7

________ patches and ______ pitting may also be seen in tuberous sclerosis

Answer 7

SHAGREEN patches and ENAMEL pitting may also be seen in tuberous sclerosis

Question 8

what causes the epilepsy/seizures in tuberous sclerosis?

Answer 8

cortical tubers

Question 9

name the 2 important proteins and 2 important chromosomes in tuberous sclerosis

Answer 9

tuberin (chromosome 9) and hamartin (chromosome 16)

Question 10

mTOR control what?

Answer 10

mTOR control cell division

Question 11

what is the treatment for tuberous sclerosis?

Answer 11

topical rapamycin treatment

Question 12

what has a:

(a) high penetrance but low frequency
(b) low penetrance but high frequency

Answer 12

(a) mutations - mendelian disorders

(b) SNPS and CNVs - common disorders

Question 13

born at term after normal pregnancy

some skin loss noted

24 hours later - widespread blistering and skin loss

diagnosis?

Answer 13

epidermolysis bullosa (EB)

Question 14

name the 3 types of EB

Answer 14

simplex
junctional
dystrophic

Question 15

EB aquisita is a ____ __________ condition

Answer 15

EB aquisita is a RARE AUTOIMMUNE condition

Question 16

autosomal dominant:

disease is seen in ___ generations

__% risk of affected child if parent is affected

Answer 16

autosomal dominant:

disease is seen in ALL generations

50% risk of affected child if parent is affected

Question 17

autosomal recessive:

disease is often only seen in ___ generation

__% risk of affected child if parent is affected

Answer 17

autosomal recessive:

disease is often only seen in ONE generation

25% risk of affected child if parent is affected

Question 18

14 year old boy presents with multiple asymptomatic coffee coloured flat marks which have been appearing over the last few years

general health is good with slight learning difficulties

diagnosis?

Answer 18

neurofibromatosis type 1

Question 19

more than how many cafe au lait macules suggest genetic disease?

Answer 19

> 5

Question 20

what are neurofibromas?

Answer 20

soft neural tumours

Question 21

name the features of NFT1

Answer 21

cafe au lait
neurofibromas
plexiform neuroma
axillary or inguinal freckling
optic glioma
2 or more Lisch nodules
a distinctive bony lesion

Question 22

name the important protein in NFT1

Answer 22

neurofibromine

Question 23

name the treatment for neurofibromatosis

Answer 23

MEK inhibitors

Question 24

baby develops red, roughened patched sos skin at 2 weeks of age

at 9 months of age, the child’s skin is itchy & broken; sleep is disturbed because of scratching

throughout childhood there are itchy red patches of skin that come & go

diagnosis?

Answer 24

atopic eczema

Question 25

name the important gene in atopic eczema and what mutations in it cause

Answer 25

filaggrin

mutations cause ichthyosis vulgaris (hyperliner palms)