Multiple Endocrine Neoplasia Type 1 (MEN1)

This chapter focuses on multiple endocrine neoplasia type 1 (MEN1) which is an autosomal dominantly inherited syndrome. The syndrome is characterized by the occurrence of tumors of the parathyroid glands, the pancreatic islets, the anterior pituitary gland and the adrenal glands as well as neuroendocrine tumors in various organs. Parathyroid adenomas are often the first clinical presentation of MEN1 and majority of patients develop this adenoma. The genetic pathophysiology of MEN1 involves inactivating germline mutations of the MEN1 gene, located on chromosome 11. The gene is a tumor suppressor and inactivation of MEN1 gene is required for the development of tumors. The method for MEN1 gene mutation analysis involves direct DNA sequence analysis and large deletions encompassing one or more MEN1 exons usually escape detection which necessitates the inclusion of an assay to detect such alterations. Mutation analysis enables MEN1 disease gene carriers to be identified and periodic clinical monitoring makes presymptomatic detection and treatment of MEN1-associated tumors possible.