This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Psychiatry
[{'content': 'X-linked recessive disorder with mental retardation and self mutilation is seen in - \nSelect and explain. \nA. Lesch - Nyhan syndrome, B. Fragile X - syndrome, C. Down syndrome, D. All of the above', 'role': 'user'}, {'content': "Answer: A \nExplanation: X-linked recessive disorder causing MR :- Lesch - Nyhan syndrome, Hunter's syndrome.\nSelf-mutilation behavior is seen in Lesch - Nyhan syndrome.", 'role': 'assistant'}]