Human coagulation factor V along with coagulation factor serves as a cofactor in thrombin formation by coagulation factor X. Generation of thrombin leads to fibrin and clot formation. In this study 45 patients were selected with venous thrombosis and evaluated first by the coagulation test for the presence of activated protein C (APC) resistance and then evaluated genetically by restriction enzyme analysis for the presence of factor V Leiden. 9(21%) patients had activated protein C resistance by the modified coagulation assay. When analyzed by restriction analysis, 7 (17%) had the factor V Leiden mutation. The present study shows that factor V Leiden has a lower frequency in the Iranian patients with venous thrombosis compared to the western societies.
