Recurrent Venous Thrombosis: Is there a Place for Methylenetetrahydrofolate Reductase Polymorphisms?

Venous thrombosis (VT) is a multifactorial disease due to the interplay of acquired and inherited prothrombotic causes and environmental factors [1]. Several genetic thrombophilic conditions have been identified, including polymorphisms of the methylene tetrahydrofolate reductase (MTHFR) [2]. MTHFR reduces methylene tetrahydrofolate to 5-methyl tetrahydrofolate and transfers a methyl group to homocysteine, forming methionine. When present in homozygothy, the two common polymorphisms, C677T and A1298C, have been associated with decreased enzyme activity resulting in hyperhomocysteinemia (HCY) [3]. HCY is a well-known risk factor for vascular diseases, including ischemic heart disease, cervical arterial dissection, stroke and venous thrombosis in healthy population [4]. Routine screening for inherited hypercoagulable disorders is not indicated for all patients with VT but should be performed in selected cases [5,6]. We report a case of a young woman with massive recurrent VT with recognized composed heterozygosity in MTHFR gene.