Monoclonal gammopathy of undetermined significance (MGUS) - Paraproteinaemias

Monoclonal gammopathy of undetermined significance (MGUS)

Definition

An abnormal clone of plasma cells producing a mildly raised monoclonal immunoglobulin without features of multiple myeloma.

Aetiology/pathophysiology

The immunoglobulin secreted is normally IgM. It polymerises and causes a mild increase in plasma viscosity. Unlike multiple myeloma there are preserved levels of normal immunoglobulins, no lytic bone lesions and no renal failure.

Investigations

Electropheresis of serum protein demonstrates a raised monoclonal band within the immunoglobulin region, without suppression of other proteins.

Management

A proportion of patients will go on to develop multiple myeloma and therefore all patients require followup looking for any increase in monoclonal protein levels or the development of lytic bone lesions.