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': 'Which among the following is the most frequent manifestation of MEN 1? \nSelect and explain. \nA. Parathyroid hyperplasia, B. Pituitary adenoma, C. Adrenal adenoma, D. Bronchial carcinoids', 'role': 'user'}, {'content': 'Answer: A \nExplanation: MEN 1 is an autosomal dominant disorder due to a defect in 11q13, which encodes for a 610-amino-acid nuclear protein, menin. Patients with MEN1 develop hyperparathyroidism due to parathyroid hyperplasia in 95-100% of cases, pituitary adenomas in 54-80%, adrenal adenomas in 27-36%, bronchial carcinoids in 8%. Ref: Harrisons Principles of Internal Medicine, 18th Edition, Page 3060.', 'role': 'assistant'}]