genetic conditions

Question 1

possible features of the hands and feet in a child with Down syndrome

Answer 1

• single transverse palmar crease
• absent middle phalanx of the 5th finger
• big “saddle” gap between first and second toes

Question 2

aetiology of Fragile X syndrome

Answer 2

X linked condition due to a mutation in an unstable triplet repeat on the X chromosome

Question 3

children with Down syndrome are at an increased risk of which medical conditions

Answer 3

• congenital heart disease - commonly ASD, AVSD and VSD
• conductive deafness
• vision impairment
• hypothyroidism
• duodenal atresia
• leukaemia
• low IQ
• early onset AD
• polycythaemia

Question 4

what results on first trimester screening are suggestive of Down syndrome

Answer 4

• increased nuchal translucency

- high bHCG and PAPP-A

Question 5

aeitology of Klinefelter’s

Answer 5

47 XXY karyotype

Question 6

when is Turner’s syndrome usually diagnosed

Answer 6

• childhood with short stature

- adolescence with failure of puberty

Question 7

most important risk factor for Down syndrome

Answer 7

maternal age

Question 8

aetiology of down syndrome

Answer 8

trisomy 21 - 90% due to non-disjunction at first meiotic division

Question 9

clinical presentation of children with fragile X syndrome

Answer 9

• overgrowth (prominent jaw, forehead and nasal bridge, long and thin face, large protuberant ears, macroorchidism)
• high arched palate
• hyperextensibility
• decreased IQ (mild-mod)
• shy personality with ADHD

Question 10

possible features of the cranium in a child with Down syndrome

Answer 10

mild microcephaly
flat occiput
3rd fontanelle

Question 11

possible features of the eyes in a child with Down syndrome

Answer 11

upslanting palpebral fissures
inner epicanthal folds
speckled iris
nystagmus

Question 12

clinical features on examination of a child with Turner’s syndrome

Answer 12

• poor growth, short stature
• delayed/absent pubertal development
• webbed neck
• cubitus valgus
• short 4th metacarpals/metatarsals
• systolic murmur

Question 13

associated conditions in a child with Prader Willi

Answer 13

insatiable appetite as children

mild/moderate ID

Question 14

which medical conditions are associated with Noonan syndrome

Answer 14

• cardiac problems (typically pulmonary stenosis)
• feeding problems
• pyloric stenosis
• reduced/normal IQ
• delayed puberty

Question 15

what results on second trimester screening are suggestive of Down syndrome

Answer 15

• increased bHCG

- decreased aFP, inhibin A and oestradiol

Question 16

possible features of the face in a child with down syndrome

Answer 16

protruding tongue
large cheeks
small nose
low flat nasal bridge

Question 17

aetiology of Turner’s syndrome

Answer 17

complete or partial absence of the second X chromosome in phenotypic females (mostly due to a sporadic mutation)

Question 18

possible features of the ears in a child with Down syndrome

Answer 18

low set
small
overfolded upper helix

Question 19

aetiology of Noonan syndrome

Answer 19

autosomal dominant mutation affecting the RAS-MAPK pathway

Question 20

which medical conditions are associated with Turner’s syndrome

Answer 20

primary amenorrhoea
congenital heart defects
poor social skills

Question 21

clinical features on examination in a child with Noonan syndrome

Answer 21

(Very similar to Turner’s syndrome)

• short stature
• face - wide set eyes, low set ears, inverted triangular shaped face, webbed neck)
• chest - widely spaced nipples, pectus deformity
• systolic murmur
• cryptorchidism