Moreover, the expression of miR-21-3p and miR-181d-5p differentiated the presence of RPGN and correlated with AKRiS in renal tissue samples, respectively, while miR-181a-5p differentiated MPO- from PR3-positive AAV-GN in renal tissue and serum samples. The gene discussed is MPO; the disease is rapidly progressive glomerulonephritis.