F2 and hereditary thrombophilia due to congenital protein S deficiency: Although the main limitation of this study is its retrospective nature and a complete set of thrombophilic investigations might not have been performed in some of these cases in the last 10 years, it should be noted that hereditary thrombophilic disorders such as Factor V Leiden, prothrombin gene G20210A mutation, protein C deficiency, protein S deficiency, antithrombin deficiency, and methylenetetrahydrofolate reductase (MTFR) gene mutation are very rare in the Southeast Asian population [32,33].