Multiple Endocrine Neoplasia Syndromes (MEN)

 MEN syndromes

a. Autosomal dominant inheritance with incomplete penetrance
b. Characterized by hyperplasia and tumors of endocrine glands

2. MEN I (Werner syndrome)

a. Features tumors of the pituitary gland, parathyroids, and pancreas
b. Associated with peptic ulcers and the Zollinger-Ellison syndrome
c. Genetic mutation of MEN I gene

MEN II (lla or Sipple syndrome)
a. Features medullary carcinoma of the thyroid, pheochromocytoma, and parathyroid
     hyperplasia or adenoma
b. Genetic mutation of RET proto-oncogene

MEN III (lIb)
a. Features medullary carcinoma of the thyroid, pheochromocytoma, and mucocutaneous neuromas
b. Genetic mutation of RET proto-oncogene.