Down Syndrome

Alternate Name: Mongolism, Trisomy 21

Test:

Chromosome count (trisorny 21), intrauterine chorionic villus sampling (AB). Antenatal tests that should be considered jointly: S.HCG (VH), neutrophil alkaline phosphatase (VH), S.AFP (L), S.oestriol (L), nuchal ultrasound

Sign:

Dd:

Cretinism, other chromosome translocations

Phys:

47 chromosomes with triplicate chromosome 21