Biochemical and clinical impact of reduced methylene tetrahydrofolate reductase enzyme activity

Abstract

Methylene tetrahydrofolate reductase (MTHFR) enzyme is a crucial enzyme involved in the pathway of tetrahydrofolate inter-conversion and one-carbon metabolism. Though there are 24 reported polymorphisms associated to MTHFR gene, the two most investigated are C677T (Ala²²² Val) and A1298C (Glu⁴²⁹ Ala) single nucleotide polymorphisms (SNPs). The metabolic impact in the form of hyperhomocysteinemia, redistribution of different forms of folates, altered methylation process and accumulation of unmetabolised folic acid have been reported in individuals with reduced or deficient MTHFR activity. These biochemical alterations have been associated with coronary artery diseases, various thromboembolic phenomenon, infertility and reproductive failures, cancers and inflammatory diseases. Folic acid supplementation may further worsen the case in these individuals by increasing the unmetabolised forms. Supplementation of 5-MTHF could be a better alternative for therapeutic and preventive purposes.