Comparisons were made with established EGPA and GPA control cohorts.<h4>Results</h4>Three clusters emerged: Cluster 1, a hybrid phenotype (pulmonary nodules, PR3-ANCA positivity, high relapse rate); Cluster 2, a systemic inflammatory phenotype (constitutional symptoms, PR3-ANCA positivity, moderate renal involvement); and Cluster 3, a severe vasculitis form (severe renal disease, alveolar hemorrhage). The gene discussed is PRTN3; the disease is vasculitis.