MGUS stands for Monoclonal Gammopathy of Undetermined Significance, a condition characterized by the presence in the blood of an abnormal protein called monoclonal protein or M protein, for short. It is produced in bone marrow by plasma cells, a type of white blood cell. MGUS rarely causes symptoms and is diagnosed only when the abnormal protein shows up in a blood test done for other reasons. MGUS usually causes no health problems, but over time, in up to 20 percent of all cases, it can lead to multiple myeloma (a cancer of the bone marrow involving malignant proliferation of plasma cells), as well as other types of cancer or blood diseases. The risk of progression to a serious disorder is one percent per year.
As its name suggests the cause of MGUS is unknown, although it has been associated with certain genetic changes and with exposure to pesticides and radiation. The incidence of this condition increases with age - the abnormal protein shows up in tests of three percent of adults age 50, and in 10 to 15 percent of individuals over the age of 80. MGUS is more common in men than women and occurs more frequently in African Americans than in Caucasians.
Based on the results of diagnostic tests - which can reveal the amount of M protein in the blood and urine, its exact type, and the level of involvement of plasma cells in the bone marrow - your doctor should be able to rule out any other cause of the M protein found in your blood and can assess the risk of developing a more serious disorder.
Unfortunately, there’s no cure for MGUS or any treatment that can prevent progression to a serious disease. Patients need annual checkups to make sure that levels of M protein haven’t changed or that that any change is caught early. Your diagnosis poses no risk to others in your family. Your siblings or children do not need to be screened.
No lifestyle changes can affect the protein levels in your blood. The amount of protein in the diet doesn’t influence M protein production in bone marrow. But it is still important to your general health to continue to eat a healthy diet, get regular exercise and try to reduce the stress that this diagnosis has caused.
Focus on the fact that in 80 percent of all cases MGUS doesn’t lead to a serious disease. The odds are in your favor.
Andrew Weil, M.D.