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
Hirschsprung disease has association with which of the following conditions? 
Select and explain. 
A. Von Hippel Lindau, B. MEN I, C. MEN 2A, D. MEN 2B
C: MEN 2A
Answer: C: MEN 2A 
Explanation: Small number of patients with MEN 2A have associated Hirschsprung disease. In MEN2A/Hirschsprung disease variant aganglioneuromatosis may be found throughout the colon or in smaller segments. Characteristic features of MEN 2A are medullary carcinoma of thyroid, pheochromocytoma and parathyroid adenoma. Ref: Harrisons Internal Medicine, 16th Edition, Chapter 295, Pages 2231-34.