A rare inherited disorder that affects the endocrine glands, which release hormones into the bloodstream. The disorder, also known as Wermer's syndrome, can cause multiple tumors in the parathyroid and pituitary glands and in the pancreas. These tumors are almost always benign, but they can cause the glands to become overactive and secrete abnormal levels of hormones. Those abnormal secretions, in turn, can cause a variety of medical problems, ranging from kidney stones and fatigue to fertility problems and life-threatening ulcers.

Dr. Settara Chandrasekharappa, of the National Human Genome Research Institute's Genetics and Molecular Biology Branch, defines multiple endocrine neoplasia, type 1 (MEN1).

Related terms: gene, tumor suppressor gene.