Multiple PSA-associated variants were in genes related to infection and immunity, including HLA-A; ST6GAL1, involved in IgG N-glycosylation46; KLRG1, which regulates natural killer (NK) cell function and IFN-γ production47; and FUT2, which affects ABO precursor H antigen presentation and confers susceptibility to viral and bacterial infections48. The gene discussed is FUT2; the disease is infection.