The human methylenetetrahydrofolate reductase (MTHFR) gene encodes one of the key enzymes in folate metabolism. This gene is located on chromosome 1 (1p36.3), which has 12 exons. The aim of the present study was to investigate the possibleassociation ofthetwo (C677T and A1298C) polymorphismsof this genewith male infertility. Ina case-control study, 250 blood samples were collected from IVF centres in Sari and Babol (Iran): 118 samples were from oligospermic men and 132 were from controls. Two single nucleotide polymorphisms of the MTHFR genotype were detected using polymerase chain reaction–restriction fragment length polymorphism. There was no association found between the A1298C variant and male infertility. However, carriers of the 677T allele (CT and TT genotypes) were at a higher risk of infertility than individuals with other genotypes (odds ratio 1.84; 95% confidence interval 1.11–3.04; P¼0.0174). Structural analysis of human MTHFR flavoprotein showed that C677T transition played an important role in the change in affinity of the MTHFR–Flavin adenine dinucleotide binding site. Based on our results, we suggest that C677TtransitioninMTHFRmayincreasetheriskofmaleinfertility,anddetectionoftheC677Tpolymorphismbiomarker may be helpful in the screening of idiopathic male infertility.
