Association between Methylenetetrahydrofolate Reductase (MTHFR) and 5-Methyltetrahydrofolate-Homocysteine Methyltransferase Reductase (MTRR) Polymorphisms in Iraqi Patients with COVID-19

Background: The methylenetetrahydrofolate reductase ( MTHFR ) gene is an essential gene in the metabolism of folate-homocysteine. Recently, the level of homocysteine was found to be a significant marker in the follow-up of COVID-19 infection. Thus, this study aimed to detect the effect of genetic polymorphisms for single nucleotide polymorphisms (SNPs) (c.66A>G, c.1298A>C, and c.677CT) on COVID-19 infection. Methods: Blood samples were collected from 270 patients with COVID-19 in the medical center of Al-Shifa (Baghdad, Iraq) from November 2020 to March 2021. Tetra-primer amplification refractory mutation system-polymerase chain reaction (ARMSPCR) technique was used for the detection of genotypes of SNPs. The odds ratio (OR) was used to detect the relationship between SNPs and COVID-19 infections. Haplotype analysis was performed by SHEsis software. R esults: There was a significant difference between mild/ moderate cases and severe/critical cases for ages (35-45), (46-55), and (56-65) years (P<0.0001, P=0.01, and P=0.006, respectively). The results showed significant differences in the T allele for SNP c.677>C (P<0.0001 and OR=4.58). The C allele for SNP c.1298A>C indicated significant differences (P<0.001 and OR=3.15). Besides, the G allele for SNP c.677C>T showed significant differences (P<0.001 and OR=6.64). Consequently, these SNPs showed a predisposition to the development of COVID-19 infection. With regard to the C-A-A, T-A-A and T-C-G haplotypes indicated significant differences between the control and patient groups. The C-A-A was related to a decreased risk and indicated a protective effect against COVID-19 infection development (P<0.0001 and OR=0.218). The increased risk was associated with T-A-A and T-C-G haplotypes and indicated the risk impact on COVID19 infection development (P<0.0001, P=0.004, and OR=15.5, OR=6.772, respectively). Furthermore, the linkage disequilibrium (LD) for SNPs was studied, and the complete D' value was 99%. Conclusion: The genetic polymorphisms of SNPs (c.66A>G, c.1298A>C, and c.677C>T) in the Iraqi population were associated with COVID-19 infection.