This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Genetic and genetic disorders, 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: Majority of translocations in Down syndrome are fusions at the centromere between chromosomes 13,14,15,21 and 22.These are known as Robeson I an translocation. t(11:14 ) is not seen in down syndrome. Reference : Nelson TB of pediatrics 19th edition pg 402.