In addition to 23 MEN2A patients (including FMTC), two cases harboring germline RETM918T mutation (FUSCC-75, FUSCC-80) were classified as MEN2B due to evidence of mucosal neuroma accompanied with either pheochromocytoma (PHEO) or marfanoid body habitus (Supplementary Table S1). Here, RET is linked to hereditary pheochromocytoma-paraganglioma.