The myelodysplastic syndromes (MDS) are hematological (blood-related) medical conditions with ineffective production (or dysplasia) of the myeloid class of blood cells. Patients with MDS can develop severe anemia and require blood transfusions. In some cases, the disease worsens and the patient develops cytopenias (low blood counts) caused by progressive bone marrow failure. The outlook in MDS depends on the type and severity. Many people live normal lifespans with MDS. Often, people are asymptomatic and are unaware they even have MDS until it shows up in a routine blood test.