What is MDS?

MDS (myelodysplastic syndromes) is a group of disorders in which your blood-forming stem cells are defective and fail to make enough healthy blood cells. These diseases happen 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. To be diagnosed with MDS, you must have low blood counts for at least one blood cell type and your blood cells must look abnormal under a microscope. Doctors must examine your bone marrow to give you a definite diagnosis of MDS. The symptoms and the course of MDS are different for each person depending on which blood cells are affected.