Twenty-nine patients had syndromic PCC/PGL based on germline DNA testing: the most prevalent mutation was in the RET proto-oncogene (n = 13) followed by mutation in one of the SDH subunits (n = 11), VHL (n = 3), NF-1 (n = 2). This evidence concerns the gene SDHB and adrenal gland pheochromocytoma.