Fig. 1: Localization of MGRS-associated renal lesions.

Monoclonal gammopathy of renal significance (MGRS)-associated lesions can involve one or more renal compartments. In immunotactoid glomerulonephritis, C3 glomerulopathy and proliferative glomerulonephritis with monoclonal immunoglobulin deposits (PGNMID), MGRS-associated lesions involve only the glomeruli, whereas in light-chain proximal tubulopathy (LCPT), MGRS-associated lesions involve only the proximal tubules. MGRS-associated lesions in cryoglobulinaemic glomerulonephritis mainly involve the glomeruli but can occasionally affect blood vessels in the form of intravascular cryoglobulin thrombi or endovasculitis. Immunoglobulin-related amyloidosis and monoclonal immunoglobulin deposition disease (MIDD) usually affect all renal compartments, including glomeruli, vessels and the tubulointerstitium. GBM, glomerular basement membrane.