investigation of dysmorphic child and developmental delay

Question 1

CHARGE syndrome

Answer 1

de novo mutation CHD7 gene
Coloboma of the eye
Heart defects
Atresia of choanae
Retardation growth and development
Genital and urinary tract abnormalities
Ear abnormalities and hearing loss

Question 2

dysmorphic features

Answer 2

single features alone are fairly common in the general population. e.g epicanthic folds, or a single palmar crease
it is only in combination that these features begin to point towards a syndrome

Question 3

turner’s

Answer 3

can be a result of many chromosome abnormalities
45, X - 98% end in miscarriage
75% caused by the loss of the X or Y in paternal meiosis

Question 4

turner’s

Answer 4

can be a result of many chromosome abnormalities
45, X - 98% end in miscarriage
75% caused by the loss of the X or Y in paternal meiosis

Question 5

unbalanced robertsonian translocation

Answer 5

eg in downs
trisomy 21
instead of having 3 separate chromosome 21, the 3rd may be translocated and ‘stuck’ onto the end of another chromosome eg on chromosome 14

Question 6

unbalanced robertsonian translocation

Answer 6

eg in 2% of all downs syndrome
trisomy 21
instead of having 3 separate chromosome 21, the 3rd may be translocated and ‘stuck’ onto the end of another chromosome eg on chromosome 14

if the mother has a balanced robertsonian translocation, and has 2 chromosome 21, but one is stuck on the end of chromosome 14, she can pass on 2 chromosome 21 (one alone, one with 14) leading to trisomy

Question 7

klinefelters

Answer 7

affects males only
XXY
small testes and subsequent low levels of testosterone
lack of development of male sexual characteristics and possible development of breast tissue
Tx: testosterone replacement

Question 8

XXX syndrome

Answer 8

affects females
taller
usually learning disability
decreased muscle tone
seizures
renal problems