Multiple endocrine adenomatosis
Familial multiple endocrine neoplasia type 1 (FMEN1) is an inherited disorder that affects the endocrine glands. Normally, the hormones released by endocrine glands are carefully balanced to meet the body's needs. In patients with FMEN1, sometimes more than one group of endocrine glands, such as the parathyroid, the pancreas, and the pituitary become overactive at the same time. Most people who develop overactivity of only one endocrine gland do not have FMEN1.
Not only do the features of FMEN1 vary among members of the same family, but some families with FMEN1 tend to have a higher rate of prolactin-secreting pituitary tumors and a much lower frequency of gastrin-secreting tumours. In addition, the age at which FMEN1 can begin to cause endocrine gland overfunction can differ strikingly from one family member to another. One person may have only mild hyperparathyroidism beginning at age 50, while a relative may develop complications from tumors of the parathyroid, pancreas, and pituitary by age 20. Sometimes a patient with FMEN1 knows of no other case of FMEN1 among relatives. The commonest explanations are that knowledge about the family is incomplete or that the patient carries a new MEN1 gene mutation.
FMEN1 is quite rare, occurring in about 3 to 20 persons out of 100,000. It affects both sexes equally and shows no geographical, racial, or ethnic preferences.