Myelodysplastic syndrome (MDS) is a group of disorders caused by blood cells that are poorly formed or dont work properly. In a healthy person, bone marrow makes new, immature blood cells that mature over time. MDS occurs when something disrupts this process so that the blood cells dont mature. Instead of developing normally, the blood cells die in the bone marrow or just after entering the bloodstream. Over time, there are more immature, defective cells than healthy ones, leading to problems such as fatigue caused by too few healthy red blood cells (anemia), infections caused by too few healthy white blood cells (leukopenia), and bleeding caused by too few blood-clotting platelets (thrombocytopenia).

Most myelodysplastic syndromes have no known cause, but others are caused by exposure to cancer treatments, such as chemotherapy or radiation therapy, or being exposed to certain chemicals, including tobacco smoke, pesticides, fertilizers, and solvents such as benzene. MDS is primarily a disease of the elderly, but it can affect younger patients as well.

Management of myelodysplastic syndromes is most often intended to slow the disease, ease symptoms, and prevent complications. Common measures include blood transfusions and medications to boost blood cell production. In certain situations, a bone marrow transplant, also known as a stem cell transplant, may be recommended to replace your bone marrow with healthy bone marrow from a donor. The only cure for MDS is a successful stem cell transplant, but not everyone can have this treatment.