Familial occurrence of multiple CCMs (OMIM 116860, 603284, 603285) is associated with autosomal-dominantly inherited loss-of-function variants in one of the three genes CCM1 (KRIT1, OMIM: *604214), CCM2 (Malcavernin, OSM, *607929) or CCM3 (PDCD10, TFAR15, *609118). Here, CCM2 is linked to cerebrocostomandibular syndrome.