PRTN3 and granulomatosis with polyangiitis: Granulomatosis with polyangiitis (GPA), formerly known as Wegener’s granulomatosis, is a necrotizing vasculitis primarily affecting small- to medium-sized vessels, characterized by granulomatous inflammation and a strong association with anti-neutrophil cytoplasmic antibodies (ANCAs), particularly those directed against proteinase 3 (PR3) [1,2].