This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Disorders of Amino acid Metabolism, Subject name: Pediatrics
[{'content': "Not a feature of Hanup's disease: \nSelect and explain. \nA. Pellagroid skin lesion, B. Cerebellar ataxia, C. Mental retardation, D. Psychological disturbances", 'role': 'user'}, {'content': 'Answer: C \nExplanation: Hanup disease: Most children remain asymptomatic In symptomatic patient- cutaneous photosensitivity: pellagra-like rash on sun exposure Some patients may have intermittent ataxia & psychological disturbances, but mental development is usually normal.', 'role': 'assistant'}]