investigation of dysmorphic child and developmental delay Flashcards
CHARGE syndrome
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
dysmorphic features
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
turner’s
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
turner’s
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
unbalanced robertsonian translocation
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
unbalanced robertsonian translocation
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
klinefelters
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
XXX syndrome
affects females taller usually learning disability decreased muscle tone seizures renal problems