Monoclonal heavy chain (immunoglobulin G3) deposition disease: report of a case.

Seven cases of nonamyloid heavy chain (gamma chain) deposition disease have been previously reported. We describe one case of a 79-year-old woman presenting with proteinuria and microscopic hematuria whose renal biopsy showed nodular glomerulosclerosis with deposition of gamma3 heavy chains and complement in the glomeruli and tubular basement membranes with no associated light chain deposition. The patient did not have multiple myeloma. This case is unique in that in all previously reported cases of heavy chain deposition disease the gamma chain subtype has been either gamma1 or gamma4.