© 2010 Myeloma UK
Charity No: SC 026116
Myeloma UK,
Broughton House,
31 Dunedin Street,
Edinburgh EH7 4JG
MGUS stands for Monoclonal Gammopathy of Unknown Significance and is characterised by the presence of an abnormal antibody (protein) in the blood and / or urine. Antibodies are produced by plasma cells, which are found in the bone marrow and are used by the body to help fight infection.
In MGUS, an abnormal antibody is produced by the plasma cells. The abnormal antibody is commonly known as paraprotein. Paraproteins have no useful function in the body and do not help to fight infection.
MGUS is a common condition in older people and is present in about 3% of people over 70 years of age. It can occasionally occur in people below the age of 70.
The causes of MGUS are unknown.
Generally, MGUS patients will not experience any symptoms and in the absence of other medical conditions, will remain well. Most MGUS patients will never develop any symptoms.
As MGUS is not associated with any symptoms, the abnormal protein is usually discovered by chance during routine or unrelated blood tests.
In MGUS the blood and / or urine tests will show:
If a bone marrow biopsy or X-rays are carried out they will show:
After a diagnosis of MGUS has been made patients will have their paraprotein levels monitored regularly. Monitoring the paraprotein level is important because there is a small chance that MGUS will develop into a cancer affecting the blood, including myeloma.
MGUS is closely associated with a cancer called myeloma. Myeloma is a type of cancer which is found in the bone marrow and is associated with problems such as bone pain and anaemia, which do not occur in MGUS. Therefore a diagnosis of myeloma needs to be ruled out.
If the paraprotein is very low, there are no symptoms, and blood tests show normal calcium and kidney function, the diagnosis is almost certainly MGUS.
Although MGUS can progress to myeloma, not all MGUS patients develop myeloma. Most patients will remain stable for many years and will not require any treatment. Data suggest that if MGUS remains stable for two years, it will then remain stable, on average, for 10 years before there is any transition to myeloma.
Unfortunately, when MGUS is diagnosed there are no definite tests to show who will progress to myeloma and who will remain stable long-term. However, this is an area of active ongoing research.
As MGUS does not cause any symptoms in the majority of patients and it does not require any treatment. However, the patient’s paraprotein levels will be monitored through regular blood tests.
Newly diagnosed MGUS patients should have a detailed medical examination and their paraprotein level monitored. Ongoing monitoring is dependent on the level and type of paraprotein at time of diagnosis and the age / preferences of the patient.
Recent guidance recommends that, following a diagnosis of MGUS, patient checks should occur every three to four months for the first year. These checks can then be reduced to every 6 - 12 months as long as no new symptoms develop.
The paraprotein levels can fluctuate somewhat in MGUS. However, any steady increase in paraprotein level or new symptoms require further tests to ensure that MGUS has not progressed to myeloma.
MGUS is a non-cancerous condition and a diagnosis of MGUS will not necessarily lead to the development of myeloma. As MGUS is a symptomless condition there is no treatment. Regular blood tests will monitor the paraprotein levels and the fact that MGUS patients are monitored closely means that, should they progress to myeloma, the myeloma can be diagnosed early.
Also, research into the genetics of MGUS continues to provide clues as to who is likely to / unlikely to progress from MGUS to myeloma. This will be useful for determining which tests and investigations patients have and how their MGUS is monitored in the future.
© 2010 Myeloma UK
Charity No: SC 026116
Myeloma UK,
Broughton House,
31 Dunedin Street,
Edinburgh EH7 4JG