Genetic information was available in 136 patients of the PHEO group, of whom 31.6% had a predisposing hereditary syndrome (27 MEN2A, 6 neurofibromatosis type 1, 4 SDHB mutations, 3 Von Hippel Lindau syndrome, 2 SDHD mutations and 1 patients MAX mutation). The gene discussed is SDHB; the disease is neurofibromatosis type 1.