Common variants at 21q22.3 locus influenceMX1gene expression and susceptibility to severe COVID-19

The COVID-19 disease, caused by the SARS-Cov-2, presents a heterogeneous clinical spectrum. The risk factors do not fully explain the wide spectrum of disease manifestations, so it is possible that genetic factors could account for novel insights into its pathogenesis.In our previous study, we hypothesized that common variants on chromosome 21, nearTMPRSS2andMX1genes, may be genetic risk factors associated to the different clinical manifestations of COVID-19. Here, we performed an in-depth genetic analysis of chromosome 21 exploiting the genome-wide association study data including 6,406 individuals hospitalized for COVID-19 and 902,088 controls with European genetic ancestry from COVID-19 Host Genetics Initiative. We found that five single nucleotide polymorphisms (SNPs) withinTMPRSS2and nearMX1gene show suggestive associations (P≤1×10−5) with severe COVID-19. All five SNPs replicated the association in two independent cohorts of Asian subjects while two and one out of the 5 SNPs replicated in African and Italian populations, respectively (P≤0.05). The minor alleles of these five SNPs correlated with a reduced risk of developing severe COVID-19 and increased level ofMX1expression in blood.Our findings provide further evidence that host genetic factors can contribute to determine the different clinical presentations of COVID-19 and that MX1, an antiviral effector of type I and III interferon pathway, may be a potential therapeutic target.