Monoclonal gammopathy of significance

The presence of a monoclonal protein in the serum and/or urine is a common clinical condition that increases in incidence with age. Although the diagnosis is most often monoclonal gammopathy of undetermined significance (MGUS) there are many conditions associated with the presence of a monoclonal protein in a patient. Several of these are potentially life-threatening and the presence of the M protein should serve as a clue to these diagnosis. The size of the monoclonal protein has very little bearing on the association with other disorders. This concise review highlights the better known associations between monoclonal proteins and other symptoms, making them monoclonal gammopathy of clinical significance.