Familial Multiple Endocrine Neoplasia Type I: A New Look at Pathophysiology

FAMILIAL multiple endocrine endocrine neoplasia type I (FMENI) is a complex hereditary disorder encompassing pancreatic and pituitary tumors and hyperplasia of the parathyroid glands. Hyperparathyroidism is the most frequently expressed endocrinopathy in the syndrome which may also include one or more of the following: hyperinsulinism, Zollinger-Ellison syndrome, pancreatic cholera, acromegaly, Cushing's syndrome, and hyperprolactinemia. The earliest suggestion of such a complex syndrome generally is thought to be Erdheim's description (1) of parathyroid enlargement and pituitary adenoma discovered coexisting at autopsy. Rossier and Dressler (2) reported on two siblings with Cushing's syndrome, hypoglycemia, and kidney stones. In 1945 Shelbourne and McLaughlin (3) observed another subject displaying hypoglycemia, kidney stones, and a pituitary adenoma. Wermer (4) described several cases of multiple glandular hyperfunction in a family and called attention to the likely genetic nature of the disorder. In 1968 Steiner and his colleagues (5) reported that the syndrome could be divided into two classes, MENI (pituitary, pancreatic, and parathyroid involvement) and MENII (thyroid medullary cancer plus adrenal medullary and parathyroid disease).