The IFIH1 gene variants rs1990760 and rs2111485 are associated with COVID-19 susceptibility and affect IFIH1 protein levels in Iraqis

Interferon-induced helicase C domain-containing protein 1 (IFIH1) is one of the main pattern recognition receptors that sense viral RNA and activate host cells to mount an effective antiviral immunity.

A case–control study (90 patients with mild/moderate COVID-19 and 90 matched controls) was performed to explore the association of two variants of the IFIH1 gene with COVID-19 risk using the tetra-primer amplification refractory mutation system-polymerase-chain-reaction method. The first is a missense variant, rs1990760 C/T, and the second is an intergenic variant, rs2111485 A/G. In addition, serum IFIH1 levels were assessed using an ELISA kit.

Mutant alleles (T and G, respectively) and corresponding homozygous genotypes (TT and GG, respectively) of both variants were significantly associated with increased risk of COVID-19. IFIH1 levels were significantly higher in patients compared to controls and were favorably affected by the rs1990760 and rs2111485 mutant-type genotypes.

IFIH1 protein showed up-regulated levels in the serum of patients with mild/moderate COVID-19. In addition, the IFIH1 gene variants rs1990760 C/T and rs2111485 A/G were associated with susceptibility to COVID-19, and the study suggests that their mutant-type genotypes are not only associated with increased risk of COVID-19 but also contributed to higher serum IFIH1 levels.