MTHFR Gene-Polymorphism and Infertile Men in Indian Population: A Systematic Literature Review.

Single nucleotide polymorphisms (SNPs) in the genetic makeup of the methylenetetrahydrofolate reductase gene ( C677-T, A1298-C, and G1793-A) alongside environmental and lifestyle component has shown some links as a potential factor responsible for male infertility across the globe posing huge genetic vulnerability to the gender. However, SNPs in the  gene implicated in male infertility are not without their own controversial results even within the same population. The goal of this study was to provide comprehensive insights into the controversial nature of  gene polymorphism on male infertility across all Indian populations as well as other ethnicities. The electronic PubMed database was utilized to conduct and select eligible studies for this systematic review (update to December 2021). Only high-quality studies with a link between  polymorphisms and male infertility were included based on our exclusion and inclusion criteria. The connection between the  gene polymorphism and male infertility in Indian population studies was evaluated using odds ratios (ORs) with a 95% confidence interval (CI). A total of five studies presenting 1,237 cases and 1,044 controls were assessed for this study. The collective results revealed that C667-T and A1298-C gene polymorphism were significantly linked with an increased chance of male infertility both in south India and north India, however, with some conflicting results. Interestingly, no study has been carried out to investigate the impact of G1793-A polymorphism on infertile males in the Indian population at the time of our report. Results generated from the few case-control evaluated on  gene polymorphism in the Indian population are found to conflict with some extrinsic factors (such as nutritional status-folate metabolism, lifestyle, varying recruitment procedures, and epigenetic elements) identified to have played some critical roles. Therefore, broader studies across all regions in India addressing the grave impact of  gene polymorphism on male infertility are of utmost importance.