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Myelodysplastic Syndromes

Medically reviewed by Last updated on Feb 5, 2024.

What are Myelodysplastic Syndromes?

Harvard Health Publishing

Myelodysplastic syndromes (MDS) are diseases in which the bone marrow does not make enough healthy blood cells. Bone marrow is the soft, inner part of bones. Normally, it produces three kinds of blood cells:

Healthy bone marrow makes immature cells called stem cells that develop into red and white blood cells and platelets.

In MDS, the bone marrow cannot produce enough of the right kind of blood cells. These abnormal cells either die in the bone marrow or soon after they enter the bloodstream. As a result, people with MDS don't have enough healthy blood cells and are said to have low blood cell counts. This can lead to:

Many experts consider MDS an early stage of cancer. In about 30% of patients, the disease will develop into acute myeloid leukemia (AML), a cancer of bone marrow cells. That's why this condition is sometimes referred to as a "pre-leukemia" or a "pre-leukemic" state.

In most cases, the cause of MDS is not known. The biggest risk factor for MDS is having had treatment for cancer with chemotherapy and radiation therapy. Exposure to certain chemicals has also been linked to MDS. Some people may be born with a tendency to develop MDS.

Most patients with MDS are over age 60. The disorder is slightly more common in men than women. It is also slightly more common in whites than in other racial groups.


Many people with MDS have no symptoms. It's often diagnosed after a person has a complete blood count (CBC) for some other reason. Most often the first sign is a low red blood cell count (anemia).

MDS can cause fatigue, fevers, weight loss, and other symptoms. However, these problems can often be signs of other blood-related illnesses. Consult your doctor if you experience:

The symptoms of MDS depend on which blood cell type is involved and on their levels in your blood. People with a low red cell count may look pale. They may also feel weak, tired, or short of breath. People with a reduced white blood cell count are more prone to bacterial infections and high fevers. People with a low platelet count tend to bruise and bleed easily.


Your doctor will ask about your symptoms, health habits, and past illnesses and treatments. Your doctor will also order tests to evaluate your blood. A laboratory will check the number, shape, and size of the blood cells.

Another test for MDS is a bone marrow biopsy. This involves taking a small sample of bone and liquid bone marrow from the hipbone. The patient's skin is numbed, and the sample is removed with a long needle. A pathologist (a specially trained doctor) looks for abnormalities in the cells under a microscope.

Genetic tests including the identification of mutations in the genes of the blood cells may be done, too.

After the exams and tests, your physician will "score" your MDS to help determine the severity of the disease. Your risk score is based on three factors:

Scores range from 0 (low risk) to more than 2 (high risk).

Expected Duration

Progression of MDS depends on the type of cells that are missing, your risk score, and other factors.


The biggest risk factor for MDS is previous cancer treatment. Exposure to certain chemicals, such as benzene, may trigger MDS. Although doctors do not know whether smoking raises the risk of MDS, it is a risk factor for AML and several other cancers.


The treatment for MDS depends on your type of MDS and your risk score, as well as your age and overall health. Patients with MDS are often treated by a hematologist or oncologist, doctors who specialize in blood disorders.

Symptoms MDS, such as fatigue and infections, can be eased with blood transfusions. During a transfusion, your doctor replaces your missing red or white blood cells or platelets with cells from another person through a vein in your arm.

Your doctor may also inject growth factors similar to naturally occurring substances made in the bone marrow. They stimulate increased production of blood cells. One growth factor stimulates the production of red blood cells. It can be combined with another growth factor that stimulates the production of white blood cells.

Depending on the type of MDS that you have, your doctor may prescribe vitamins, antibiotics to treat infections, or other drugs. Several drugs are available for the treatment of MDS.

Some patients receive chemotherapy, which kills abnormal cancer cells like those found in AML.

Recently, some specific genetic defects have been associated with MDS. Your doctor may want to test your bone marrow cells for these abnormalities. If present, a more specific type of therapy may be given.

Chemotherapy drugs are usually taken by mouth or injected into a vein or muscle. The drugs harm cancer cells, but they can damage healthy ones, too. They can also cause side effects, including:

There are ways to lessen these side effects.

An aggressive treatment called a stem cell transplant offers a potential cure for some MDS patients. The chance for a cure is higher for young people and those whose disease has not begun turning into leukemia.

In this procedure, stem cells (immature blood cells) are removed from a donor's blood. The patient has high-dose chemotherapy and (often) radiation therapy. The patient then receives the donor's stem cells through a transfusion. These cells travel to the bone marrow and begin making white blood cells, platelets, and red blood cells.

You will need various tests and exams during and after your treatment for MDS. These can show how well the treatment is working, whether your condition has changed, and what side effects to expect.

When To Call a Professional

Call your doctor if you notice any of these symptoms:


The outlook for people with MDS depends on its cause, the type of blood cell affected, severity of symptoms, the person's age, and other factors. The bone marrow's failure to produce healthy cells happens gradually, so MDS is not necessarily fatal. But some people die from the complications of low blood counts, such as infections and uncontrolled bleeding. For about 30% of people with MDS, the disease turns into leukemia.

Additional Information

National Cancer Institute (NCI) (part of the National Institutes of Health)NCI Public Inquiries Office6116 Executive BoulevardRoom 3036ABethesda, MD 20892-83221-800-4-CANCER (1-800-422-6237)TTY: 1-800-332-8615

American Cancer Society (ACS)1599 Clifton Road, NEAtlanta, GA 30329-4251Toll-Free: 1-800-ACS-2345 (1-800-227-2345)TTY: 1-866-228-4327

Myelodysplastic Syndromes FoundationP.O. Box 353, 36 Front St.Crosswicks, NJ 08515Toll-Free within US: 1-800-MDS-0839

Leukemia & Lymphoma Society

1311 Mamaroneck Ave.White Plains, NY 10605(914) 949-5213Toll-Free: 1-800-955-4572

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.