- Trisomy 21 (47, XX or XY, +21) due to nondisjunction in meiosis (usually maternal, incidence goes up with maternal age) - mosaicism - parent is a balanced carrier (Robertsonian translocation) and passes this on, so person with DS has unbalanced translocation of 21 and another acrocentric chromosome (ex. 14...46, XY, t(14q21q)

- newborns: floppy, hypotonia - webbed neck - ID - distinctive facial features (flat nasal bridge, small mouth, large tongue, small eyes) - short stature - brushfield spots - ear infections due to malformation of ear - excessive joint flexibility - high incidence of AVSDs/VSDs - extra space between big toe and first little toe

DS Flashcards by Sarah Minney

DS-genotype

Trisomy 21 (47, XX or XY, +21) due to nondisjunction in meiosis (usually maternal, incidence goes up with maternal age)
mosaicism
parent is a balanced carrier (Robertsonian translocation) and passes this on, so person with DS has unbalanced translocation of 21 and another acrocentric chromosome (ex. 14…46, XY, t(14q21q)

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DS-phenotype

newborns: “floppy,” hypotonia
webbed neck
ID
distinctive facial features (flat nasal bridge, small mouth, large tongue, small eyes)
short stature
brushfield spots
ear infections due to malformation of ear
excessive joint flexibility
high incidence of AVSDs/VSDs
extra space between big toe and first little toe

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DS-diagnosis and screening

fetal screening: quad test, ultrasound, amnio, CVS

diagnosis: karyotype

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DS Flashcards

(3 cards)