PRTN3 and anti-neutrophil cytoplasmic antibody-associated vasculitis: In comparing the current study to previous reports in adult-onset AAV, specifically the RAVE trial describing baseline clinical manifestations of adult-onset AAV, the mucous membranes/ocular and ENT systems are more frequently involved in PR3-ANCA versus MPO-ANCA seropositive disease, in both paediatric-onset and adult-onset cases.12 Focusing on the frequency of pulmonary involvement, no differences were observed between PR3-ANCA and MPO-ANCA seropositive adults in the RAVE trial cohort12 or in our paediatric small vessel vasculitis cohort.