A novel MEN1 mutation in a Japanese adolescent with multiple endocrine neoplasia type 1

[Introduction] Multiple endocrine neoplasia type 1 (MEN1; OMIM 131100) is an autosomal-dominant hereditary endocrine tumor syndrome. It is characterized by the combined development of anterior pituitary adenomas, adenomas or hyperplasia of the parathyroid glands, and gastroenteropancreatic neuroendocrine tumors (GEPNETs) in a single patient. Germline mutations in the menin gene (MEN1) account for the development of MEN1, and most of the MEN1 mutations are inactivating, which is consistent with the tumor-suppressing role of menin. More than 1000 different germline MEN1 mutations have been reported throughout the entire length of the coding and noncoding regions without significant clustering. Of all mutations, approximately 23% are nonsense mutations, 41% are frameshift deletions or insertions, 6% are in-frame deletions or insertions, 9% are splice-site mutations, and 20% are missense mutations.