Gain of function mutations in OAS1 lead to autoinflammatory disease in humans [55]; polymorphisms at the OAS1 locus are associated with type 2 diabetes [56], a pre-existing condition associated with severe COVID-19 disease [57]; and genetic variation at DPP9 is associated with the risk of developing pulmonary fibrosis [58]. Here, DPP9 is linked to type 2 diabetes mellitus.