We studied a family in which 4 persons from three generations had multiple cavernous malformations ("angiomas") of the central nervous system (CNS) and/or retina and found accounts in the literature of sixteen other families with this condition. In these families with familial cavernous malformation of the CNS and retina, 92% of pathologically documented vascular malformations were cavernous; 50% of those subjects affected had multiple CNS and/or retinal vascular malformations and 68% (excluding probands) were symptomatic. Cutaneous vascular lesions were an inconsistant manifestation. Autosomal dominant inheritance with high penetrance was confirmed.