The background was that 40-45% of apparently sporadic PHAEO or paragangliomas are hereditary and germline mutations are found in VHL (von Hippel-Lindau tumor suppressor, E3 ubiquitin protein ligase), SDHB/C/D (succinate dehydrogenase complex, subunit B, subunit C, subunit D) and RET (ret proto-oncogene) [7]. Here, RET is linked to paraganglioma.