SERPINA1 and autoimmune disease: In brief, genome-wide association studies (GWAS) have revealed that PR3-ANCA vasculitis is associated with the genes SERPINA1 (encoding alpha-1 antitrypsin), PRTN (encoding PR3), and in line with other autoimmune diseases, human leukocyte antigen (HLA) loci, including HLA-DP4, while MPO-ANCA vasculitis has been reported to be associated with HLA-DQ [10,20].