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
[{'content': 'One year old male child with sparse blond hair, developmental delay and tremors, diagnosis \nSelect and explain. \nA. Albinism, B. Phenylketonuria, C. Cerebral palsy, D. Infantile tremor syndrome', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Phenylketonuria is due to deficiency of enzyme phenylalanine hydroxylase or of its cofactor tetrahydrobiopterin ;leads to accumulation of phenylalanine in body fluids and brain. It is mainly characterized by profound mental retardation ,lighter complexion and neurologic symptoms like tremors,hyperreflexia and spasticity. Reference: Nelson TB of pediatrics 19th edition, pg 418', 'role': 'assistant'}]