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
Mousy odor of urine is seen in 
Select and explain. 
A. Isovaleric acidemia, B. Phenyl ketonuria, C. MSUD, D. Tyrosinemia
B: Phenyl ketonuria
Answer: B: Phenyl ketonuria 
Explanation: Children with classic phenyl ketonuria have an unpleasant odour of urine due to presence of phenylacetic acid,which is often described as musty or mousey. Phenylketonuria is due to deficiency of enzyme phenylalanine hydroxylase or of its cofactor tetra hydro biopterin. Reference: Nelson TB of pediatrics pg 418 edit