C3 and Dowling-Degos disease 1: Immune-complex mediated MPGN is characterized by the glomerular deposition of polyclonal or monoclonal immunoglobulins (Ig), whereas C3 glomerulopathy [comprising of C3GN and dense deposit disease (DDD)] is characterized by the glomerular deposition of C3 in the absence of Ig deposition (115, 117, 118).