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)