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
All of the following may occur in Down&;s syndrome except 
Select and explain. 
A. Hypothyroidism, B. Undescended testis, C. Ventricular septal defect, D. Brushfield's spots
B: Undescended testis
Answer: B: Undescended testis 
Explanation: Congenital or acquired hypothyroidism,brush field spots in iris,and ventricular septal defect IS seen in a case with down syndrome. Undescended testis is not a feature. Reference: Nelson TB of pediatrics 19th edtn pg 402