2009). The familial form (OMIM 116860, 603284, 603285) accounts for up to 20% of all cases and is inherited in an autosomal dominant manner. Heterozygous loss‐of‐function mutations in CCM1 (KRIT1; OMIM *604214), CCM2 (Malcavernin/OSM; *607929), and CCM3 (PDCD10; *609118) have been associated with CCM. The gene discussed is PDCD10; the disease is cerebral cavernous malformation.