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Monoclonal gammopathy of undetermined character
Last reviewed: 07.07.2025
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In monoclonal gammopathy of undetermined significance, M-protein is produced by non-malignant plasma cells in the absence of other manifestations of multiple myeloma.
The incidence of monoclonal gammopathy of undetermined significance (MGUS) increases with age, from 1% in people aged 25 years to 4% in people over 70 years. MGUS may occur in combination with other diseases in which the M protein may be due to antibodies produced in large quantities in response to a prolonged antigenic stimulus.
[ Symptoms and diagnosis of monoclonal gammopathy
Monoclonal gammopathy of undetermined significance is usually asymptomatic, but peripheral neuropathy may occur. Although most cases are benign, 25% (1% per year) progress to B-cell tumors, myeloma, or macroglobulinemia.
M-protein in blood or urine is usually detected incidentally during routine examinations. In laboratory evaluation, M-protein is detected in low concentrations in serum (< 3 g/dL) or urine (< 300 mg/24 h). Unlike other plasma cell disorders, in monoclonal gammopathy of undetermined significance, the M-protein level remains stable over time, the levels of other serum immunoglobulins are normal, and in most cases there is no bone destruction, anemia, or Bence Jones proteinuria.
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Treatment of monoclonal gammopathy
There is no treatment for monoclonal gammopathy of undetermined significance. Patients should be monitored every 6-12 months with clinical examination and urine protein electrophoresis.