Abstract
C3 glomerulonephritis (C3GN) is rare. It is a proliferative glomerulonephritis resulting from glomerular deposition of complement factors due to dysregulation of the alternative pathway of complement. The association between monoclonal protein production and development of C3GN was described. We report a 74-year-old man with rapid worsening of kidney function and dialysis needed due to C3GN. In this case, serum protein electrophoresis showed no monoclonal spike but serum immunoelectrophoresis showed a lambda light chain monoclonal gammopathy. Once the diagnosis was made, the patient was treated with immunosuppression with complete kidney recovery. This case shows the importance of accurate and prompt diagnosis and appropriate treatment.