Mutations have been identified in both the gene encoding fumarate hydratase and three of the four genes encoding succinate dehydrogenase, subunits B, C and D (SDHB, -C and -D) [4-6], while no cancer-related mutations have yet been reported in SDHA. Germline mutations in FH predispose individuals to multiple cutaneous leiomyomas, uterine leiomyomas and in some families renal cell cancer (HLRCC) [7], whereas mutations in SDH cause hereditary paragangliomas and pheochromocytomas (HPGL) [8]. The gene discussed is SDHB; the disease is pheochromocytoma.