Abstract: 32yearold male with a 4month course presented with elevated serum creatinine associated with large albuminuria,no microscopic hematuria,proximal tubular injury(hypokalemia,hypouricemia,hypophosphatemia and positive of urineglucose),and bilateral kidney enlargemrnt was shown by renal ultrasound.Immunofixation electrophoresis indicatied monoclonal κ band and elevated κ free light chain(κ/λ=7692) was tested..Plasma cells were 3% and 05% respectively by bone marrow inspiration twicey,and no primitive and immature plasma cells were observed.Renal biopsy revealed formation of intracellular crystals in tubular epithelial cells.The renal tubular epithelial cells were cytoplasmic kappa lightchain positive.Electron microscopy revealed formation of intracellular crystals in tubular epithelial cells.The final diagnosis was light chain proximal renal tubular diseases.After 4 courses of bortezomib combined with dexamethasone,no M protein can be dectectd,and renal function improved,together with the decreasement of the urinary protein.