Pathology General 4ae15526 All of the following statements are true regarding down syndrome except? A Occurs due to meiotic non disjunction of chromosome 21 B Trisomy 21 C Most common CHD is enocardial cushion defect D It is the most common trisomy in humans High-Yield Explanation Most common trisomy in humans is trisomy 16,most common type of autosomal trisomy that survive upto birth in trisomy 21.