Membranoproliferative glomerulonephritis (MPGN) is a glomerular injury pattern, characterized by accentuation of the lobular architecture with endocapillary proliferation, duplication of the glomerular basement membranes, and immune complex deposition (Fig. 1). MPGN is attributed to primary (idiopathic) and secondary causes. Primary MPGN is divided into types I, II, and III, which can be distinguished on the basis of light, immunofluorescence, and electron microscopy. Type I is characterized by mesangial and subendothelial deposits. Type II (dense deposit disease) is characterized by the presence of serum C3 nephritic factor and prominent elongated intramembranous electron dense deposits that are observed within glomerular or tubular basement membranes or the basal lamina of Bowman’s capsules [ 1]. MPGN type III is similar to type I with the addition of subepithelial or...