Multiple endocrine neoplasia type 1 is caused by mutation in which gene?

• A. RET
• B. TP53
• C. MEN1
• D. VHL

Answer: (C)

Multiple endocrine neoplasia type 1 is caused by mutation in the MEN1 gene, which encodes the tumor suppressor protein menin. When MEN1 is inactivated, cells in endocrine tissues lose regulation of growth and differentiation, letting tumors develop. This syndrome is inherited in an autosomal dominant pattern and classically presents with tumors in three endocrine organs: the parathyroid (often causing primary hyperparathyroidism), the pituitary, and the pancreatic islets.

Knowing the gene helps distinguish it from other MEN syndromes: mutations in RET underlie MEN2, TP53 mutations are central to Li-Fraumeni syndrome, and VHL mutations cause von Hippel-Lindau disease. Thus, the gene associated with MEN1 is the MEN1 gene.