Myelodysplastic Syndromes (MDS)

MDS is a group of disorders where your bone marrow does not work well, and the blood-forming stem cells in your bone marrow fail to make enough healthy blood cells. People with MDS can lack the right amount of red blood cells, white blood cells, and platelets (the small cells that help blood to clot).

The disease happens because the bone marrow cells do not develop into mature blood cells. Instead, these blood cells stay within the bone marrow in an immature state. The symptoms and the course of MDS may vary greatly from person to person. These differences depend on which blood cells are affected.

All people with MDS have two things in common:

  • They have a low blood cell count for at least 1 blood cell type. This is called cytopenia.
  • Their bone marrow and blood contain blood cells with an abnormal shape, size, or look.

What does the term "myelodysplastic" actually mean?

Myelo = blood cells and Dysplastic = abnormal development or growth. So, when you have myelodysplastic syndrome, this means that your blood cells have an unusual shape and that they have abnormal growth.

Who develops MDS?

While the exact number of people who have MDS is not known, about 10,300 new cases were reported in the U.S. in 2003. This number was taken from data collected by the Surveillance, Epidemiology, and End Results (SEER) Program of the Centers for Disease Control (CDC) and the National Cancer Institute (NCI). This program only started collecting data in 2001. The number of people may be higher than reported because some doctors are not yet aware of the need to report MDS cases to a national registry. Some doctors believe that there are as many as 12,000 to 15,000 new MDS cases each year in the U.S.
We know that people diagnosed with MDS are:

  • More often men than women
  • Most often age 60 or older; the average age at diagnosis is 71
  • Most often white; Native Americans, African-Americans, Inuits, Asians, and Pacific Islanders are least likely to get MDS.