Monoclonal gammopathy of undetermined significance (MGUS)
DEFINITION
Monoclonal gammopathy of undetermined significance (MGUS) is a condition in which an abnormal protein (monoclonal protein, or M protein) is in the blood. M protein is produced by plasma cells, a type of white blood cell. Monoclonal gammopathy of undetermined significance usually causes no problems. Sometimes, monoclonal gammopathy of undetermined significance is either associated with another disease or can progress over years to other disorders, including some forms of blood cancer.
If you have monoclonal gammopathy of undetermined significance, you’ll usually have periodic checkups to monitor your level of M protein. If there’s no increase, monoclonal gammopathy doesn’t require treatment.
With close monitoring, if monoclonal gammopathy of undetermined significance does progress, you’ll get earlier treatment.
CAUSES
Monoclonal gammopathy of undetermined significance occurs when plasma cells in your bone marrow produce an abnormal protein called monoclonal protein (M protein). Plasma cells are a type of white blood cell. They are found in your bone marrow. Plasma cells produce some of the antibodies that help your body fight infection.
In the majority of people with monoclonal gammopathy of undetermined significance, the protein isn’t harmful. But when too much M protein accumulates, it crowds out healthy cells in your bone marrow and can damage other tissues in your body.
Genetic changes appear to play a role in monoclonal gammopathy of undetermined significance, as do environmental triggers.
SYMPTOMS
Monoclonal gammopathy of undetermined significance rarely causes signs or symptoms. The condition is usually detected by chance when you have a routine blood test for another problem. However, some people may experience nerve problems, such as numbness or tingling, associated with the abnormal protein.
