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: 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)