MEN1 is characterized by tumors of the parathyroid, entero-pancreatic, and anterior pituitary glands, with penetrance approaching 95% by the sixth decade of life, whereas MEN2 typically includes medullary thyroid carcinoma, pheochromocytoma, and hyperparathyroidism [1]. The gene discussed is MEN1; the disease is medullary thyroid gland carcinoma.