Clinical Course of a Patient with Alpha-Heavy Chain Deposition Disease (a Case Report)

Abstract

Heavy chain deposition disease (HCDD) is a rare entity associated with monoclonal gammopathy of renal significance. It is characterized by deposition of monoclonal heavy chain, usually gamma type, along the glomerular and tubular basement membranes and vessel walls. If left untreated, the disease progresses to ESRD within 2 years with almost inevitable recurrence in renal allograft. Apart from kidney biopsy, the workup includes monoclonal immunoglobulin testing and clonal identification, which subsequently guide the treatment; however, these tests can be negative in 20% of cases. Free light chain (FLC) ratio is characteristically abnormal in all HCDD patients and can be used for disease monitoring and assessment of treatment response. Therapy for eligible patients includes clone-directed treatment used for multiple myeloma/B cell lymphoproliferative disorders. We report a patient who presented with nephritic syndrome, underwent extensive workup including two renal biopsies, and was initially misdiagnosed with IgA nephropathy. Retrospectively, after reaching ESRD, patient was diagnosed with alphaHCDD. No clone was detected and no monoclonal immunoglobulin found. Initially, abnormal FLC ratio normalized after reaching dialysis. No extrarenal manifestations were present. Taking everything into consideration, we opted for no treatment before cadaveric kidney transplantation but to proceed with transplantation, perform protocol biopsies and treat upon any sign of disease recurrence. HCDD with negative clonal and paraprotein identification can pose a diagnostic and therapeutic challenge. In our alphaHCDD ESRD patient, we decided to proceed with kidney transplantation without prior treatment. Long-term effectiveness of this approach remains to be seen.