Genetics

Question 1

what is the important of precision medicine

Answer 1

used to identify subgroups of patients who will respond to treatment

Question 2

what is a genodermatoses

Answer 2

skin condition caused by well defined genetic cause

Question 3

what is tuberous sclerosis

Answer 3

genodermatoses- presents as infantile seizures (caused by cortical tumours- may also cause mental impairment), ash leaf molecules in skin, peuringual fibromata and longitudinal ridging in nails, facial angiofibromas, hamartomas, bone cysts, enamel pitting

Question 4

what are angiofibromas

Answer 4

erythematous papules- often misdiagnosed as acne but doesnt have comedones

Question 5

what is the inheritance pattern of tuberous sclerosis

Answer 5

autosomal dominant

multi gene disorder (chromosomes affecting tuberin, hamartin and tumour regulation)

Question 6

what is a denovo mutations

Answer 6

mutation that is present for the first time in a specific family member

Question 7

what is the risk of a child getting a autosomal dominant disorder if a parent has it

Answer 7

50%

Question 8

what is variable penetrance

Answer 8

a child with affected parent may not shoe disease

Question 9

who is most likely to get an autosomal dominant disorder males or females

Answer 9

both same chances

Question 10

what is wild type

Answer 10

typical phenotype of a species as it occurs in nature

Question 11

what is a missense mutation

Answer 11

a point mutation that results in a codon which codes for a different amino acid

Question 12

what is a nonsense mutation

Answer 12

when codon changed to a ‘stop’ codon

Question 13

what is a frameshift mutation

Answer 13

one that changes all the codes for amino acids by making DNA sequence indivisible by three

Question 14

what is penetrance

Answer 14

proportion of individuals carrying particular genotype that also expresses the phenotype

Question 15

what is epidermolysis bullosa

Answer 15

group of genetic skin fragility conditions

Question 16

what is the inheritance pattern of epidermolysis bullosa

Answer 16

can be dominant, recessive, acquired or new mutation

Question 17

what are the three main types of epidermolysis bullosa

Answer 17

simplex (splits in epidermis)
junctional (DEJ)
dystrophic (dermis)

Question 18

what genes are affected in epidermolysis bullosa

Answer 18

one controlling skin structure and adhesion

• keratin 5, 14
• laminins
• integreins
• collagen 17

Question 19

why do you need 2 types of keratin

Answer 19

to form dimer which then forms filament

Question 20

what is Haploinsufficiency

Answer 20

(autosomal dominant) when one copy of an allele doesnt produce enough protein

Question 21

what is a dominant-negative disease mechanism

Answer 21

where mutation in one gene causes normal protein to stop working (normal gene interfered with mutant gene)

Question 22

what is gain of function

Answer 22

mutant protein gains a new function affecting cell processes

Question 23

what is complete loss of protein

Answer 23

autosomal recessive- 2 faulty copes of gene produce no protein

Question 24

if both parents are carrier of an autosomal recessive condition, what are the chances of a child getting it

Answer 24

1 in 4

Question 25

what are cafe au lait molecules

Answer 25

occur from birth onwards, coffe colours flat marks, >5 suggests genetic disease (e.g neurofibromatosis)

Question 26

what are neurafibromas

Answer 26

soft neural tumours

Question 27

what are the symptoms of neurofibromatosis type 1

Answer 27

cafe au lait, neurofibromas, plexiform neuroma, axiallary or inguinal freckling, optic glioma

Question 28

is atopic eczema dominant or recessive

Answer 28

recessive- most common recessive in UK

Question 29

why does filaggrin mutation cause atopic diseases

Answer 29

as reduces skin barrier function, making patients more susceptible to allergens