A genetic disease was identified in 14 of the 54 patients with PPGL (seven with multiple endocrine neoplasia type 2, two with von Hippel-Lindau disease, two with neurofibromatosis, two with succinate dehydrogenase mutation B, and one with PGL-3 locus mutation). The gene discussed is SDHC; the disease is multiple endocrine neoplasia type 2.