This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Inborn Errors of Metabolism, Subject name: Pediatrics
[{'content': "Mutation seen in Hartnup's disease: \nSelect and explain. \nA. SLC6A 18, B. SLC6A 19, C. SLC6A 17, D. SLC6A 16", 'role': 'user'}, {'content': "Answer: B \nExplanation: b. SLC6A 19(Ref: Nelson 20/e p 3160)Hartnup's disease is due to mutation of SLC6A 19 gene encoding the neutral amino acid transporter, resulting in deficiency of nicotinamide synthesis", 'role': 'assistant'}]