Patients with MPO-ANCA GN all had a positive serum MPO-ANCA assay and presented with severe renal disease with an estimated glomerular filtration rate (eGFR) of 30 ± 8 (median ± 28.20 with a minimum of 10 and maximum of 105, mL/min/1.732) compared with MCD that had the expected normal renal function (eGFR 100 ± 6). Here, MPO is linked to kidney disorder.