Lyons et al. demonstrated that EGPA is a polygenic disease and identified 11 loci associated with EGPA in a cohort of 676 European adult cases: BCL2L11, TSLP, HLA-DQ, 10p14, CDK6, IRF1/IL5, BACH2, LPP, GPA33, HLA and 12q21 [71]. This evidence concerns the gene IRF1 and eosinophilic granulomatosis with polyangiitis.