Multiple endocrine neoplasia type 1 syndrome. A rare, inherited disorder that affects the endocrine glands and can cause tumors in the parathyroid and pituitary glands and the pancreas. These tumors (usually benign) cause the glands to secrete high levels of hormones, which can lead to other medical problems, such as kidney stones, fertility problems, and severe ulcers. In some cases, tumors inside the pancreas can become cancerous. Also called multiple endocrine adenomatosis and Wermer's syndrome.