Anti-glomerular basement membrane (anti-GBM) disease is typically characterized by autoimmunity against the α3 chain of type IV collagen. Rarely, circulating autoantibodies are not detected. These atypical cases follow a more indolent clinical course, and underlying mechanisms, including alternative target antigens, require investigation. In this issue of Kidney International, Kuang et al. describe a case of anti-GBM disease with autoantibodies against the GBM component laminin-521 and demonstrate that laminin-521 is pathogenic in a rat model of anti-GBM glomerulonephritis.