Introduction & objectives: Methylenetetrahydrofolate reductase (MTHFR) has a critical role in spermatogenesis process, and alteration in the expression level of this gene may leads to male infertility. In this study we evaluated the effects of promoter methylation of MTHFR on the risk of oligozoospermia. In addition, we performed an in silico analysis to approve our laboratory results. Materials & Methods: In this case-control study, semen samples were collected from 73 oligozoospermic and 75 healthy control men. The genomic DNA was extracted from semen samples by boiling method. We convert unmethylated cytosine to thymine by Epitect Bisulfite kit. After bisulfite treatment, the promoter region of MTHFR was amplified by Methylation Specific PCR method (MSP). Some in silico tools such as MotifSof, CisRed, and CustomTrack software were used for evaluation of promoter region of MTHFR. Results: Our data revealed a significant association between CpG island promoter methylation and risk of oligospermia (p=0.022). By using in silico software we observed no TATA box, a strong nucleosome exclusion region (NXR), and six PROSITE motifs in promoter region of MTHFR. Also, there are 14 transcription factor binding sites in the promoter region which directly involve in spermatogenesis process. Conclusion: According to the findings, the prevalence of methylation in promoter region of MTHFR can be a useful molecular biomarker to predict the predisposition of male infertility.
