Hereditary hemorrhagic telangiectasia is described in four generations of a kinship. The family is unique in that three generations manifest central nervous system vascular disease, which was pathologically confirmed in two generations. Genetic linkage was not identified for 32 genetic markers studied. The literature is reviewed for patients with central nervous system arteriovenous malformations and hereditary hemorrhagic telangiectasia. The pathogenesis of the disease is discussed, and therapeutic modalities are considered.