The first and most significant locus described in GWAS associated with COVID-19 critical is 3p21.31, which encompasses six genes (SLC6A20, LZTFL1, CCR9, FYCO1, CXCR6, and XCR1) (The Severe COVID-19 GWAS Group, 2020). The gene discussed is CXCR6; the disease is COVID-19.