Monoclonal gammopathy of undetermined significance is a benign condition marked by the presence of M protein in the blood. They are produced in place of antibodies when the body combats an infection. This is a harmless condition and does not affect the health of an individual. Most of its cases are seen in old people above 70 years. It usually does not have signs and symptoms. Its causes can be genetic or environmental. The levels of M proteins remain steady for a long time. In a few cases, they may get overloaded in the bone marrow and can cause cancers like multiple myeloma, lymphoma, and others.


Who Is At Risk For MGUS Or Monoclonal Gammopathy Of Undetermined Significance?

The following are the risk factors for monoclonal gammopathy of undetermined significance:

Age- The chances of getting monoclonal gammopathy of undetermined significance increases with age. It develops in old age. It is mostly diagnosed at 70 years. It is more prevalent in the age of 85 years or above.


Sex- it is more common in men than in women.

Race- its incidence in any specific race is not clear. Its cases are more seen in Africans and African Americans. They are more common in black people than white people. Native Asians are less likely to be affected.


Family History- monoclonal gammopathy of undetermined significance is more likely to occur in people who have a family history of MGUS.

Environment Factors- people who are exposed to pesticides are more risk to develop MGUS. Immunosuppressed people are more likely to get affected by MGUS.

Most cases of monoclonal gammopathy of undetermined significance are without any sign or symptom. This disease is diagnosed accidentally in a blood test done for other conditions. In rare cases, the following symptoms are present-

  • Tingling sensation
  • Numbness due to nerves involvement
  • Weakness in the nerves
  • Rashes or irritation in the skin
  • Bone loss or bone fractures.

Causes Of Monoclonal Gammopathy Of Undetermined Significance

Monoclonal gammopathy of undetermined significance is caused due to the production of M protein. It is produced by abnormal plasma cells. These proteins do not impact the normal health of the affected people. When M proteins get deposited in the healthy cells, it can damage the involved tissues in the body. It gets mostly accumulated in the bone marrow that can affect other healthy tissues in the body. Its exact cause is not clear. It can occur due to genetic abnormalities or environmental reasons.

Complications Of Monoclonal Gammopathy Of Undetermined Significance

Monoclonal gammopathy of undetermined significance can lead to the accumulation of excess M protein in the body that may progress into cancer in a few cases. The cancerous diseases that can be caused by MGUS are-

  • Multiple Myeloma
  • Lymphoma
  • AL amyloidosis
  • light chain deposition disease
  • Waldenstrom macroglobulinemia.

MGUS or monoclonal gammopathy of undetermined significance is a condition characterized by the production of monoclonal proteins or M proteins or paraproteins. They are formed from white blood cells in bone marrow. They are circulated in the blood. They are produced in response to an infection. The body begins to produce them in place of usual antibodies. This disease is a slowly progressive disease and the presence of M proteins does not harm the health of a person. It does not require any treatment.

The old people are more prone to develop in this disease. It erodes bone and reduces its density leading to bone fractures. It may take 25 years or more to progress to serious complications like multiple myeloma, lymphomas, light chain deposition disease, etc. This disease is often associated with other diseases. The patient is advised to have regular check-ups for their signs and symptoms and levels of M protein to keep watch on its progress to serious illness.


Monoclonal gammopathy of undetermined significance is a benign condition that leads to slow accumulation of M protein in bone marrow and other parts of the body; Old people especially who are above 70 years and above are more affected by monoclonal gammopathy of undetermined significance. Black people especially Africans are more likely to catch the disease.

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Pramod Kerkar

Written, Edited or Reviewed By:


Pain Assist Inc.

Last Modified On: February 14, 2019

This article does not provide medical advice. See disclaimer


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