Corresponding Author

Mahmoud M. Alseoudy

Subject Area

Medical Biochemistry and molecular biology

Article Type

Original Study


Background: Host genetic variability has been suggested as an important explanation for inter-individual differences in COVID-19 susceptibility and severity. Most vitamin D actions in the regulation of immunity are mediated by vitamin D receptors (VDRs). Polymorphisms in the VDR gene have been associated with several health outcomes; however, their effects on COVID-19 still need more clarification. This study aims to investigate the association of the VDR SNP (rs11568820, Cdx-2) with susceptibility and inter-individual variability of the severity of COVID-19. Methods: A total of 100 confirmed COVID-19 patients and 100 age and sex-matched controls were enrolled in this study between July and September 2021. COVID-19 patients were further subdivided into severe (n=50) and non-severe (n=50) cases. All participants were subjected to genotyping of Cdx-2 SNP using the allelic discrimination of the Real-time PCR technique and assay of serum 25(OH)D levels by ELISA. Results: The results showed that the homozygous ‘GG’ genotype was significantly higher in patients vs. controls, whereas the heterozygous ‘AG’ genotype was significantly lower in COVID-19 patients. Thus, the heterozygous ‘AG’ genotype is considered the protective genotype. This protection was more significant among males vs. females (P=0.02). However, there were no statistically significant differences in the genotype distributions of VDR Cdx-2 SNP between severe and non-severe patients. Moreover, COVID-19 patients with the ‘AG’ genotype presented higher 25(OH)D levels than the ‘GG’ genotype(P=0.02). Conclusions: VDR SNP (rs11568820, Cdx-2) might be a potential risk factor for COVID-19, particularly among male patients.

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.