Multiple endocrine neoplasia, type 1 (MEN 1), sometimes called Wermer's syndrome, is a rare disorder that causes tumors in the endocrine glands and parts of the small intestine and stomach. In MEN 1, the endocrine glands — usually the parathyroids, pancreas and pituitary — grow tumors and release excessive amounts of hormones that can lead to disease. However, the tumors are usually noncancerous (benign).

The excess hormones can cause a wide variety of signs and symptoms, such as tiredness, bone pain, fractures and kidney stones, as well as stomach or intestinal ulcers. Although MEN 1 can't be cured, regular testing can detect problems, and doctors can provide treatment as needed.

MEN 1 is an inherited disorder, meaning people who have the gene mutation can pass it on to their children. Each child has a 50 percent chance of inheriting the disorder.