A Family with Reduced Plasminogen Activator Activity in Blood Associated with Recurrent Venous Thrombosis

6 members of a family with a tendency to thrombosis and defective fibrinolysis were examined. After stimulation of plasminogen activator release from the vessel wall by local venous occlusion or by submaximal physical exercise, they had a lower plasminogen activator activity in blood than a healthy control group (P less than 0.01). 5 of the examined members suffered from recurrent venous thrombosis. The defect appeared to be autosomal dominant.