Relationship between CDX2 rs11568820 and EcoRV rs4516035 polymorphisms on the vitamin D receptor gene with susceptibility to different SARS-CoV-2 variants.

Several studies have revealed that vitamin D deficiency is linked to an increased risk of developing coronavirus disease 19 (COVID-19). In individuals with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections, vitamin D receptor activation is required to decrease acute respiratory distress syndrome. The purpose of this study was to examine the genotypic distribution and allelic frequencies of CDX2 rs11568820 and EcoRV rs4516035 polymorphisms in COVID-19 patients with various SARS-CoV-2 variants. For genotyping of CDX2 rs11568820 and EcoRV rs4516035 polymorphisms, we used the polymerase chain reaction-restriction fragment length polymorphism technique in 1734 and 1450 recovered and deceased patients, respectively. The results indicated the rate of COVID-19 mortality was associated with CDX2 rs11568820 AA and GA genotypes in the Delta variant and with CDX2 rs11568820 AA in the Omicron BA.5 variant, while no association was shown in the Alpha variant. Therefore, the rate of COVID-19 mortality was associated with EcoRV rs4516035 TC and CC genotypes in the Delta variant, while no association was shown in the Alpha and Omicron BA.5 variants. According to our analysis, the T-G haplotype was more common in all SARS-CoV-2 variants. The C-A haplotype was associated with COVID-19 mortality in the Delta and Omicron BA.5 variants, and the T-A haplotype was related to the Alpha variant. In conclusion, the genotype frequencies of the CDX2 rs11568820 and EcoRV rs4516035 polymorphisms between SARS-CoV-2 variants were significantly different between the deceased patients and recovered patients. However, more studies should be done to confirm the results.