VHL, RET, NF1, SDHB, and SDHD are major susceptibility genes, accounting for 90% of familial pheochromocytomas/paragangliomas, whereas TMEM127, SDHA, SDHC, SDHAF2, and MAX are minor susceptibility genes responsible for 10% of these tumors. This evidence concerns the gene SDHD and pheochromocytoma.