Summary

In the past decades considerable progress has been made in theunderstanding of inherited and acquired causes of venous thrombosisand their clinical impact (1). Thus, the risk of a first venous thrombosisis approximately 10-fold increased in subjects with deficiency of antithrombin,protein C or S (1, 2), 7-fold increased in patients withcancer (3), or the antiphospholipid antibody syndrome (4, 5), and 3 to5-fold in carriers of the G1691A allele in the coagulation factor V geneand the G20210A allele in the prothrombin gene (6-8). All together,these conditions can be identified in more than 50% of patients with afirst episode of venous thrombosis (1, 2, 8).