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: Medicine
[{'content': 'Most common genetic mutation associated with Hirschsprung disease is: \nSelect and explain. \nA. RET gene, B. END3 gene, C. ATP 7A, D. EDNRB gene', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Genetic studies have identified mutations in different genes contributing to the development of Hirschsprung disease. The more common mutations are RETgene (7-35% of sporadic cases), EDNRB gene (7%) END3 gene (5%) Ref: Seminars in Pediatric Surgery (2008) 17, 266-275.', 'role': 'assistant'}]