MPO and microscopic polyangiitis: GN is associated with both GPA and MPA in a higher proportion in children compared to adults across various studies (65–78% vs. 50–65% in GPA and 88–95% vs. 70–85% in MPA, respectively), and overall there was no association between ANCA positivity or ANCA titre and renal remission in children, while in adults, a higher relapse rate was seen in PR3 vs. MPO—ANCA-positive cases [21].