Impact of methylene-tetrahydrofolate reductase gene C677T and A1298C polymorphisms as a risk factor for hepatitis B virus infection.

Chronic hepatitis B infection caused by Hepatitis B virus (HBV), influences over two billion people worldwide despite having an effective vaccine. With a total prevalence of 4.57%, there are 3.3 million estimated HBV carriers in Türkiye. Methylene-tetrahydrofolate reductase (MTHFR) arrange folate metabolism through nucleic acid synthesis and DNA methylation. C677T (rs1801133, p.Ala222Val) and A1298C (rs1801131, p.Glu429Ala) polymorphisms of MTHFR gene have effect of reducing the activity of enzyme. We purposed to investigate the correlation between C677T and A1298C polymorphisms of MTHFR gene with HBV infection in a Turkish population. One hundred eighteen HBV-infected participants and ninety healthy controls were incorporated in this research. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay was applied to discover the genotypes of MTHFR polymorphisms. We demonstrated that T allele and CT + TT genotype frequencies of C677T polymorphism were significantly increased in HBV-infected participants than healthy controls [ p  = 0.015, OR (95% Cl) = 1.7 (1.11-2.79) and p  = 0.020, OR (95% Cl) = 1.9 (1.10-3.42), respectively). No significant associations were noted concerning the A1298C polymorphism ( p  > 0.05). CC-AA composite genotype was observed to be significantly elevated in healthy controls than HBV-infected participants (32.2% vs. 13.6%, p  = 0.001). In addition, the frequency of T-C haplotype was found to be considerably higher in the patient group than control group (15.8% vs 11.8%, p  = 0.018). In conclusion, we found that T allele of C677T polymorphism poses a risk factor for HBV infection. We also discovered a protective impact of the CC-AA composite genotype against HBV infection and a risk effect of the T-A haplotype for HBV-infection.