MEN2 is a hereditary disease resulting from mutations of the RET protooncogene subclassified into MEN2A (MTC, pheochromocytoma, and primary hyperparathyroidism) and MEN2B (MTC, pheochromocytoma, Marfanoid habitus, mucous neuromas, and intestinal ganglioneuromatosis). This evidence concerns the gene RET and hereditary disease.