This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Proteins and Amino Acids, Subject name: Biochemistry
A 2-year-old intellectually disabled child is having blue eyes, blonde hair and fair skin. He also has a peculiar body odour. What is the diagnosis? 
Select and explain. 
A. MSUD, B. Isovaleric Aciduria, C. Phenylketonuria, D. Canavan's disease
C: Phenylketonuria
Answer: C: Phenylketonuria 
Explanation: Ans. C. PhenylketonuriaBlue eyes, blonde hair and fair skin is a classical description of a case of PKU. The child is Intellectually disabled and they have mousy body odour.