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: Pediatrics
[{'content': 'A 6 year old boy presents with progressive weakness in muscles, and difficulty in walking upstairs. He has difficulty in walking on his toes and has a waddling gait. Hypertrophy of calf muscles in noted. His CPK is the most appropriate diagnosis–levels are 10,000 LU. Which of the following is most appropriate diagnosis – \nSelect and explain. \nA. Duchenne muscular dystrophy, B. Polymyositis, C. Congenital myopathy, D. Myotonia congenita', 'role': 'user'}, {'content': "Answer: A \nExplanation: Clinical features of liV D \nThe age of onset is 2-5 years.\nEarly development of the child is normal, the disease begins to manifest when the child statrts walking.\nThe child walks clumsily, has difficulty in climbing stairs and the gait is waddling.\nHypertrophy of calf muscle is a characteristic sign and is visible by the age of 4-5 years.\nThis is called pseudohypertrophy because it is not true hypertrophy of muscles, instead the muscle is replaced by fat and connective tissues.\nPelvic girdle involvement is very common and can be elicited by Gower's sign:\nThere is characteristic involvement of the muscle", 'role': 'assistant'}]