The diagnosis of GPA relies on a combination of clinical manifestations, the detection of specific serological markers (mainly ANCA, particularly PR3-ANCA or cANCA), and distinct histopathological findings (such as necrotizing granulomas of the upper and/or lower respiratory tract, inflammation in small to medium arteries, capillaries, or small veins, or pauci-immune glomerulonephritis) [3]. This evidence concerns the gene PRTN3 and granulomatosis with polyangiitis.