Correlation between rs7041 and rs4588 polymorphisms in vitamin D binding protein gene and COVID-19-related severity and mortality.

Background: The vitamin D binding protein (DBP) plays a critical role in both innate and adaptive immune systems, participating in several clinical conditions, including coronavirus disease 2019 infection severity, and mortality rate. The study aimed to investigate the correlation between rs7041 and rs4588 polymorphisms in the DBP gene and Coronavirus Disease-2019 (COVID-19) severity and mortality, in patients of Suez Canal University Hospitals in Ismailia, Egypt.

Methods: A case-control study enrolled 220 individuals; 140 COVID-19 patients and 80 healthy controls. Serum 25(OH) vitamin D levels were determined by the enzyme-linked immunosorbent assay (ELISA), and rs7041 and rs4588 polymorphisms of the DBP gene were genotyped using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

Results: The study found that both groups had vitamin D deficiency, which was considerably lower in the COVID-19 patients group compared to controls. Among COVID-19 patients, there was a significant difference in vitamin D levels according to the disease severity indicating that vitamin D levels can be used as predictors of COVID-19 severity. Negative significant correlations between genetic variants rs4588 CA genotype and genetic variants rs7041 TT genotype and COVID-19 prevalence (p = 0.006 and 0.009 respectively) were proved. No significant correlations between all the genetic variants of both rs4588 and rs7041 and COVID-19 severity (p > 0.05). Positive significant correlations between both genetic variants rs4588 CA genotype and genetic variants rs7041 TG genotype and COVID-19 mortality (p = 0.029 and 0.031 respectively).

Conclusion: vitamin D deficiency increased the severity of COVID-19. The DBP polymorphism correlated with vitamin COVID-19 prevalence and mortality.