Atypical hemolytic uremic syndrome (aHUS) is a relatively rare disorder 
described by the triad of hemolytic anemia, thrombocytopenia, and renal failure. 
Atypical HUS could be genetic, acquired, or idiopathic (without known genetic 
changes or environmental triggers). Monoclonal protein has uncommonly been 
reported as a cause of microangiopathic hemolytic anemia (MAHA). We report a 
59-year-old white man who presented with acute kidney injury (AKI) with MAHA and 
was given a diagnosis of aHUS with monoclonal gammopathy. His kidney function 
and proteinuria worsened with persistent hemolysis despite eculizumab and later 
cyclophosphamide and prednisone treatment. He responded well to VRD (bortezomib, 
lenalidomide, and dexamethasone) regimen. Renal function, proteinuria, and 
hemolysis all improved, and he was been in remission for more than 15 months. To 
our knowledge, this is the first report of successful treatment with 
bortezomib-based regimen for a patient with aHUS and monoclonal protein 
refractory to eculizumab therapy.