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Disease Profile

Monoclonal gammopathy of undetermined significance

Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.


US Estimated

Europe Estimated

Age of onset





Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.


Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable


Other names (AKA)



Monoclonal gammopathy of undetermined significance (MGUS) is a condition in which an abnormal protein called monoclonal protein is detected in the blood. MGUS typically does not cause any problems, although some affected people may experience numbness, tingling or weakness. In some cases, MGUS may progress over time to certain forms of blood cancer (such as multiple myeloma, macroglobulinemia, or B-cell lymphoma). MGUS is thought to be a multifactorial condition that is likely associated with the effects of multiple genes in combination with lifestyle and environmental factors. People with MGUS are usually monitored closely to ensure that the levels of monoclonal protein do not rise and other problems do not develop. Those with stable levels of monoclonal protein typically do not require treatment.[1][2]


Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

    Learn more

    These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

    Where to Start

    • The International Myeloma Foundation provides information on monoclonal gammopathy of undetermined significance.
    • MayoClinic.com has an information page on monoclonal gammopathy of undetermined significance.
    • The Merck Manual provides information on this condition for patients and caregivers.

      In-Depth Information

      • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
      • The Merck Manual for health care professionals provides information on Monoclonal gammopathy of undetermined significance.
      • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
      • PubMed is a searchable database of medical literature and lists journal articles that discuss Monoclonal gammopathy of undetermined significance. Click on the link to view a sample search on this topic.


        1. Monoclonal gammopathy of undetermined significance (MGUS). Mayo Clinic. May 2013; https://www.mayoclinic.org/diseases-conditions/mgus/basics/definition/con-20026422.
        2. Suzanne R Fanning, DO. Monoclonal Gammopathies of Uncertain Origin. Medscape Reference. 2016; https://emedicine.medscape.com/article/204297-overview#a0104.