Monoclonal gammopathies are conditions in which abnormal proteins (antibodies) are found in the blood. These proteins are produced from a small number of plasma cells in the bone marrow. Plasma cells are a type of white blood cell. Their main job is to make antibodies to fight infection. 1
The most common condition linked with these abnormal proteins is monoclonal gammopathy of undetermined significance (MGUS). It is not cancer. But people with MGUS have a greater risk of getting serious diseases of the bone marrow and blood. 1
MGUS causes no symptoms. In fact, monoclonal protein in the blood is often found by accident when doing other routine blood work. Most people who have abnormal proteins in their blood will never get worse. But in some cases, these illnesses can develop:1
Multiple myeloma
Non-Hodgkin lymphoma
Plasma cell leukemia
Primary amyloidosis
Solitary plasmacytoma
Waldenstrom’s macroglobulinemia1
The exact cause of MGUS is not known. Infection, immune system problems, and the environment may play a role. But experts have not found a clear link yet. Experts do know that the abnormal proteins are not caused by a certain diet or from eating dietary proteins.1
The chance of getting MGUS grows with age, but it is not common. There is no risk for monoclonal gammopathies in first-degree family members.1