Inherited thrombophilias are a heterogeneous group of coagulation disorders that predispose individuals to thrombosis, and include mutations of the factor V Leiden, prothrombin G20210A gene mutation, methylenetetrahydrofolate reductase (MTHFR) gene mutation, antithrombin III deficiency and protein C, S deficiencies (8). The gene discussed is MTHFR; the disease is deep vein thrombosis.