[Genetic and molecular bases of paragangliomas]

Paragangliomas and pheochromocytomas are neuroendocrine tumors arising in the extraadrenal and adrenal medulla, respectively. These tumors appear in certain familial syndromes, such as multiple endocrine neoplasia types 1 and 2, Von Hippel Lindau disease, neurofibromatosis type 1 and familial paraganglioma syndromes. The latter syndromes show a strong association with germline mutations of succinate dehydrogenase subunits, such as SDHB, SDHC and SDHD. This enzyme complex is related to tumorigenesis through mechanisms involved in cell proliferation, apoptosis, and alterations in oxygen sensing function, although none of these factors has been clearly identified as a cause of tumoral development. In the last few years, several studies have been performed of these genes in relation to correct diagnosis of paraganglioma and pheochromocytoma, as well as determination of germline mutations in familial and sporadic cases and its utility in genetic counselling in these patients.