Monoclonal Gammopathy of Renal Significance with Deposits of Infrequent Morphology: Two Case Reports of Light and Heavy Chain Deposition Disease with Atypical Presentation and Literature Review.

Background: Monoclonal immunoglobulin deposition disease (MIDD) includes three entities: light chain deposition disease (LCDD), heavy chain deposition disease (HCDD) and light and heavy chain deposition disease (LHCDD). The renal presentation can manifest with varying degrees of proteinuria and/or nephrotic syndrome, microhematuria, and often leads to end-stage renal disease. Given the rarity of LHCDD, therapeutic approaches for this condition remain inconclusive, as clinical trials are limited.