C3 and immunoglobulin-mediated membranoproliferative glomerulonephritis: <h4>Background</h4>C3 glomerulopathy (C3G) and immune complex-mediated membranoproliferative glomerulonephritis (IC-MPGN) represent a continuous spectrum of a glomerular disease driven by dysregulation of the complement and characterized by C3 deposition alone or associated with immunoglobulins.