Monoclonal gammopathy of renal significance
Monoclonal gammopathy of renal significance (MGRS) are a group of kidney disorders that present with kidney damage due to nephrotoxic monoclonal immunoglobulins (M proteins) secreted by clonal plasma cells or B cells. By definition, people with MGRS do not meet criteria for multiple myeloma or other hematologic malignancies.
Source: Wikipedia — Monoclonal gammopathy of renal significance (CC BY-SA 4.0)