Multiple endocrine neoplasia-1 (MEN-1) is an autosomal dominant inherited syndrome that occurs due to inactivating mutations of the MEN1 gene locus, coding for a tumor-suppressor protein, menin. The components of MEN-1 are hyperparathyroidism due to multiple parathyroid adenomas, pancreatic neuroendocrine tumors, and pituitary adenomas, in addition to some less common neoplastic manifestations. Care of people with MEN-1 requires knowledge of the problems that may arise, and the best approaches to detect and care for the manifestations of this incurable, but manageable, disease. (C) 2005 Wiley-Liss, Inc.