Multiple endocrine neoplasias type 2B and RET proto-oncogene

Multiple Endocrine Neoplasia Type 2 B (MEN 2B) is a rare autosomal dominant complex neoplastic neurocristopathy characterized by the development of a number of tumors including medullary thyroid carcinoma (MTC) and pheochromocytoma (Pheo) with gastrointestinal symptoms, marphanoid facies and multiple ganglioneuromas (GN)/ganglioneurofibromas(GNf) [1]. MTC is present in 100% of MEN 2B cases, and it often already appears in the 1st decade of life [2]. MTC is the main cause of death in MEN 2B patients who don't receive early or prophylactic treatment. Surgical treatment of MTC is the only effective therapy in cases with localized tumor.Molecular analysis of the RET gene (REarranged during Transfection) has changed the history of this syndrome, as it allows the identification of MEN 2B mutations in asymptomatic patients, and let to perform prophylactic thyroidectomy in children. RET mutations can also be responsible for MEN 2A syndrome (MTC, PC and hyperparathyroidism) or familial MTC (FMTC). The same RET gene is causative for Hirschsprung's disease (HSCR) in a variable percentage of patients and HSCR can be associated with MEN 2 [3-8]. The molecular analysis has given an important contribution to understand Ret protein functions and the correlation between genotype and phenotype in RET mutations carriers.According to genetic diagnosis, RET mutation analysis can provide early diagnosis and treatment of such a rare syndrome as MEN 2B, and becomes part of an international protocol responding these requirements.Although the importance of the neural crest (NC) was first identified over a century ago, it has gained wide acceptance in vertebral development over the last 20 years [9]. The neural crest cells contribute to the formation of structures through-out the body. Therefore, 1 out 3 human congenital malformations involves structures related to NC.Diseases arising from NC are particularly diverse in clinical presentation, including endocrinologic, cutaneous, neurological,