<prompt> Down syndrome - all are seen except -t 14; 21t 11: 14Trisomy 21t 15: 21  <response>: Ans. is b i.e., t 11: 14 o In 95 of cases of Down syndrome-trisomy of 21:-Extra chromosome is of maternal in origin.1 have mosaic with some all have 46 chromosome, a 4 have robertsonian translocation.t 13 : 21t 14 : 21t 15 : 21o Very rarely tong arm of chromosome 21 is triplicate Partial trisomy. 