The majority of hereditary pheochromocytoma and paraganglioma (PPGL) is caused by germline mutations in the SDHB, SDHC, or SDHD genes, which encode three (SDHB, SDHC, SDHD) of five subunits of succinate dehydrogenase (SDH) enzyme (SDHA, SDHDB, SDHC, SDHD, SDHAF2). The gene discussed is SDHC; the disease is pheochromocytoma-paraganglioma.