Classification of MGRS based on the ultrastructural findings of the monoclonal deposits. *Includes non-MGRS kidney diseases, such as anti-glomerular basement membrane (glomerular basement membrane (GBM) disease, membranous nephropathy, and Henoch-Schonlein purpura (HSP). These are presumed to be due to a monoclonal protein acting as an autoantibody (against antigen on glomerular basement membrane in anti-GBM disease and PLA2R in membranous nephropathy). Notably, a single subclass restriction (IgG1κ), absence of PLA2R staining, and associated proliferative changes on renal biopsy are indicative of MGRS in occasional cases of membranous nephropathy with monoclonal immunoglobulin.³⁷  Rare cases of HSP with IgA nephropathy have been associated with monoclonal IgA or MM. These patients experience frequent relapses and a high recurrence rate postrenal transplantation.⁹  FG, fibrillary glomerulopathy; Ig, immunoglobulin; ITG, immunotactoid glomerulonephritis.