DPP9 and COVID-19: Rs2271616-T (SLC6A20), rs10490770-C, rs11385942-GA (LZTFL1), rs1886814-C (FOXP4), rs72711165-C (TMEM65), rs505922-C (ABO), rs10774671-A (OAS1), rs77534576-T (TAC4), rs2109069-A (DPP9), and rs74956615-A (TYK2) was reported to increase the risk of SARS-CoV-2 susceptibility and poor COVID-19 outcomes such as critical illness, hospitalization, and respiratory failure, while rs11919389-C (ZBTB11), rs912805253-T (ABO), rs2834167-G (IL10RB), rs4767027-C (OAS1), rs1819040-A (KANSL1), rs4801778-T (PLEKHA4), and rs13050728-C (IFNAR2) decrease these risks (5–9).