Typically, the clinical manifestations of MEN2 patients include medullary thyroid carcinoma (MTC) and pheochromocytoma (PHEO); the different combinations of the endocrine neoplasia with or without nonendocrine diseases give rise to the following independent phenotypes/diseases: MEN2A, MEN2B and FMTC (which is recognized as a variant of MEN2A). This evidence concerns the gene RET and Neoplasm of the endocrine system.