This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pediatrics
Down Syndrome, All are seen except? 
Select and explain. 
A. t(14 ; 21), B. Trisomy 21, C. t(11 : 14), D. t (15 :21)
C: t(11 : 14)
Answer: C: t(11 : 14) 
Explanation: Ans. is 'c' i.e., t (11:14) In 95% of cases of Down Syndrome - trisomy of 21 Extra chromosome is of maternal in origin 1% have mosaic with 46 chromosomes o 4% have robesonian translocation. t (13 : 21) t(14:21) t (15 : 21) o Very rarely long arm of chromosome 21 is triplicate (Paial trisomy)