Cerebrovascular disease is one of the missions of this Institute and we have initiated a study of the role of excessively elevated plasma lipids on the pathogenesis of strokes. The initial phases of this investigation include: 1) The incidence of strokes in patients with primary hyperlipoproteinemia, 2) Assessment of relative frequencies of strokes in various types of primary hyperlipoproteinemia. The specific laboratory methods include: determination of partitioned plasma lipids and lipoproteins in fasting state.