Myelodysplastic syndromes (MDS) are a group of blood disorders in which the proliferation of abnormal or malignant precursor cells in the bone marrow results in a disordered and ineffective production of the myeloid lineage, which includes red blood cells, white blood cells and platelets. In MDS, blood cells in the bone marrow and circulation may have abnormal (dysplastic) cell morphology.
When initially diagnosed, approximately 80% of patients with MDS have anemia (low red cell counts and low hemoglobin). Chronic anemia is the predominant clinical problem in lower risk disease. Many patients with anemia become dependent on red blood cell transfusions. Other peripheral cytopenias (low numbers of white blood cells and platelets) may also occur.
MDS is the most common of the myeloid malignancies. There are approximately 12,000 reported new cases of MDS in the United States every year and an estimated 60,000 people living with the disease. Up to 30% of patients with MDS develop acute myelogenous leukemia (AML).