A subsequent renal biopsy revealed crescentic glomerulonephritis and interstitial nephritis with negative immunofluorescence (IgA (+/−), IgG (−), C3 (−), C4 (−), C1q (−), and Flb (−)), which is consistent with ANCA-associated pauci-immune glomerulonephritis. This evidence concerns the gene C3 and crescentic glomerulonephritis.