MDS, or myelodysplastic syndromes, is a group of similar blood disorders in which the bone marrow does not function properly and does not produce enough healthy blood cells. People with MDS typically have low blood cell counts, which means they have abnormally low levels of red blood cells, white blood cells, and/or platelets in the bloodstream.
The word "syndromes" is used in MDS because the symptoms and the course of the disease can vary greatly from person to person and by type of MDS.
Although MDS can strike people of different ages, it occurs most frequently in adult men over 60 years of age.
Approximately 40,000 to 45,000 people in the US have MDS. It is estimated that a total of 12,000 to 15,000 or more new MDS cases are diagnosed in the US each year.
To understand how MDS develops, you should know a few things about how bone marrow works. Bone marrow is the soft spongy material that fills the center of the bones.
Normal bone marrow acts like a factory that produces as many blood cells as the body needs. Bone marrow produces 3 types of blood cells:
- Red blood cells, which bring oxygen to all parts of the body
- White blood cells, which fight infection
- Platelets, which help to form blood clots and stop bleeding
All blood cells originate from a basic type of cell in bone marrow called a "stem cell." Stem cells are parent cells that make copies of themselves and give rise to generations of immature blood cells, called "blasts." Blasts, in turn, mature into the different types of blood cells needed by the body.
With MDS, there is a defect in one of the stem cells, and this defect is passed on to all the future generations of cells that develop from it. The defect prevents the stem cells from producing mature, functioning blood cells. In some cases, defective stem cells die too early or cause healthy stem cells to die too early. In other cases, defective stem cells may crowd out and overwhelm healthy stem cells so that the marrow is not able to produce enough normal blood cells.
The result is that people with MDS have too many abnormal cells in the marrow and not enough healthy cells in the bloodstream.
Read more about:
- Causes and symptoms
A review of possible causes of the disease, and an overview of possible symptoms.
- Diagnosis
Descriptions of the blood and bone marrow tests used to diagnose MDS.
- Resources
Websites and publications offering additional information.
Remember: This website is NOT intended to replace open discussions with your healthcare professional about MDS and its treatment. You should always talk to your healthcare professional first about any problems related to how you feel or about treatments you are prescribed.