A rare, genetic disorder that affects the endocrine glands and can cause tumors in the thyroid gland, parathyroid glands, and adrenal glands. The affected endocrine glands may make high levels of hormones, which can lead to other medical problems such as high blood pressure and kidney stones. MEN2 syndrome is caused by a mutation (change) in a gene called RET, and is divided into three subtypes (MEN2A, MEN2B, and FMTC). People with all subtypes of MEN2 syndrome have an increased risk of medullary thyroid cancer, pheochromocytoma, and parathyroid gland cancer. Also called MEN2, multiple endocrine adenomatosis type 2, and multiple endocrine neoplasia type 2 syndrome.