Monoclonal gammopathy of undetermined significance (MGUS)
Monoclonal gammopathy of undetermined significance (MGUS) is a blood condition that happens when plasma cells (a type of white blood cell) develop unusually in your bone marrow.
MGUS in itself isn't harmful and is unlikely to make you feel unwell, so it doesn't usually need treatment.
However, we know that a small number of people with MGUS (1% every year) go on to develop blood cancer. Because of this, you'll have regular blood tests to check that MGUS isn't developing into blood cancer.
What is monoclonal gammopathy of undetermined significance (MGUS)?
We all have small numbers of plasma cells in our bone marrow, each of which makes different antibodies which fight infections when we are sick. If you have MGUS, a particular plasma cell predominates resulting in a group of identical plasma cells producing an identical antibody, even though there isn’t an infection.
We don't know exactly what causes MGUS, but it does become more common as people get older and is more common in men, black people from an African background, people with health conditions that affect their immune system, and people with a family history of MGUS.
MGUS symptoms and diagnosis
People with MGUS usually have few or no symptoms. Rarely, some people have numbness or tingling in their hands and feet, or problems with their balance.
MGUS is often found during a blood test carried out for some other reason. To confirm a diagnosis of MGUS, you’ll usually have blood tests and urine tests. You may also have other tests to rule out myeloma or lymphoma.
Does MGUS need treatment?
MGUS doesn’t need treatment. However, because of the risk of MGUS developing into blood cancer, you’ll be monitored regularly. You should always check with your doctor if you experience any new or unusual symptoms.
Although most people with MGUS will never experience any symptoms and remain well, being told that you, or a loved one, has MGUS can make you feel anxious or uncertain. Our Support Services Team are just a phone call or email away if you’d like to talk.
We have a fact sheet on MGUS which you can order or download for free.
Worried about anything or have questions?
If you have any questions, worries, or just need someone to talk to, please don't hesitate to contact our Support Services Team via phone or email.