Down Syndrome, All are seen except –
In 95% of cases of Down Syndrome - trisomy of 21
Extra chromosome is of maternal in origin
1% have mosaic with 46 chromosomes
4% have Robertsonian translocation.
t(13:21)
t (14 : 21)
t (15 : 21)
Very rarely long arm of chromosome 21 is triplicate (Partial trisomy)
t(14 ; 21)
Trisomy 21
t(11 : 14)
t(15 :21)