Multiple endocrine neoplasia [3 genes]

Multiple endocrine neoplasia (MEN) are dominant autosomal inheritance syndromes of which four clinical types have been described according to the affected gene: MEN type 1 (MEN1 gene), MEN type 2 (RET gene), which in turn is divided into MEN2A and MEN2B, and MEN type 4 (CDKN1B gene). They are characterized by their associated risk with other tumors, such as parathyroid tumors in MEN1, or the medullary thyroid carcinomas (MTC) in MEN2, among others. Even though a clear phenotype-genotype relation does not exist, the identification of the mutation in the germinal line of MEN1 confirms the diagnosis. On the other hand, MEN2 is associated with a theoretical 100% risk of developing MTC. The MEN2A subtype represents 80% of hereditary MTC syndromes, and MEN2B represents 5%.