Genetics of cerebrovascular disease. Stroke is a complex disease, with both genetic and environmental factors having a role in its pathogenesis. A review of past studies shows some evidence of genetic influences in the development of stroke. This is supported by studies of cardiovascular disease, which indicate major genetic influences at several levels including the development of risk factors. New approaches to phenotypic classifications, patient ascertainment, and genetic analysis will stimulate research into the role of genetics in cerebrovascular disease. 