Multivariate analysis with well-established CVT risk factors lupus anticoagulant, antiphospholipid antibodies, Protein-C deficiency, Protein-S deficiency, antithrombin deficiency, factor VIII (FVIII), Factor-V Leiden (FAK-tur five LIDE-n) and prothrombin G20210A (Factor II mutation) produced similar results. This evidence concerns the gene F8 and hereditary thrombophilia due to congenital protein S deficiency.