Genomic analysis of familial PGL/pheochromocytoma (PCC) has shown that while mutations of SDHD and SDHC are associated with PGL1 and PGL3, mutations in the large subunit genes SDHB, SDHA and SDHAF2 are associated with PGL4, PGL5 and PGL2 [95]. This evidence concerns the gene SDHB and hereditary pheochromocytoma-paraganglioma.