A retrospective family cohort study published in 2008 performed a retrospective follow–up study to assess the risk of arterial thrombosis (myocardial infarction, ischemic stroke, transient ischemic attack, or peripheral artery disease) in a large series of 468 (52% women, average age, 46 ± 17 years) protein S–, protein C–, or antithrombin–deficient subjects, relatives of patients with venous thrombosis compared with nondeficient family members [17]. The gene discussed is PROS1; the disease is myocardial infarction.