Additionally, four patients (2.9%) simultaneously met the 2022 ACR/EULAR criteria for both MPA and GPA, which tested positive for MPO-ANCA (or p-ANCA) and PR3-ANCA (or c-ANCA), with renal biopsy indicating pauci-immune glomerulonephritis. The gene discussed is MPO; the disease is microscopic polyangiitis.