Spectrum of monoclonal gammopathies

The monoclonal gammopathies are defined as heterogenous group of diseases characterized by proliferation of a single clone of plasma cells, producing immunoglobulin or light (rarely heavy) chains, which can be detected in blood or urine as monoclonal (M) protein. The most common among them is monoclonal gammopathy of undetermined significance (MGUS), the asymptomatic benign disorder, present in ~ 3% of the population aged ≥50 years. However MGUS is a pre malignant condition and may progress to symptomatic multiple myeloma or related malignancies, with annual rate of approximately 1%. The clone may also produce kidney damage, resulting from just the protein M, with different patterns of renal disease. Since the lesions are progressive and may be severe leading to a significant morbidity the term "monoclonal gammopathy of renal significance (MGRS)" has been recently introduced.