Pauci-immune glomerulonephritis (GN) without antineutrophilic cytoplasmic antibodies (ANCA) is a form of rapidly progressive glomerulonephritis comprising 10-43% of pauci-immune glomerulonephritis and characterized by the absence of ANCA. In comparison with pauci-immune GN with ANCA, patients lacking ANCA may be younger at onset of the disease and have a shorter interval from onset of the disease to diagnosis. They have fewer extra renal manifestations (e.g. involvement of lung, eye, ear, nose and throat), fewer constitutional symptoms (e.g. fever, weight loss, muscle pain and arthralgia) and a high prevalence of nephrotic syndrome and chronic renal lesions. Their prognosis is generally poorer.