MGUS- monoclonal gammopathy of undetermined significance. This is predominantly a benign condition. The risk of developing active myeloma is very low: 1%/year. Thus, after 20 years, 80% of patients have not developed active myeloma.
Table 2 - MGUS Diagnostic Criteria: All Three Required
Serum monoclonal protein and/or urine monoclonal protein level lowa
Monoclonal bone marrow plasma cells < 10%
Normal serum calcium, hemoglobin level and serum creatinine.
No bone lesions on full skeletal X-ray survey and/or other imaging if performed.
No clinical or laboratory features of amyloidosis or light-chain deposition disease.
aLow is defined as: Serum IgG < 3.0 g/dl; serum IgA < 2.0 g/dl; urine monoclonal kappa or lambda < 1.0 g/24h.
MGUS research update
A recent paper in the journal Blood from the Mayo Clinic myeloma group draws attention to the fact that some patients with monoclonal gammopathy of undetermined significance (MGUS) can have renal damage from the M-component, and even complete renal failure in some instances. They propose a new name for this subtype of patient: monoclonal gammopathy of renal significance (MGRS). This draws attention to a range of clinical problems that can emerge from the effects of the M-component in serum and/or urine produced in MGUS patients. Possible neuropathy is widely recognized, but there can also be a range of autoimmune disorders affecting muscle (myositis), skin (dermatitis), blood vessel (arteritis) and even blood components resulting in, for example, acquired hemophilia or Von Willebrand’s bleeding disorders. So we need to be more aware of
these clinical issues, which are significant and not undetermined, according to Dr. Brian G.M. Durie, Chairman and Co-founder of the IMF.