Myelodysplastic syndrome (MDS), also known as preleukemia, is another type of acquired bone marrow failure syndrome. It is most often diagnosed in adults but can develop in children and young adults after aplastic anemia or certain cancer treatments. In people with MDS, the bone marrow makes fewer red blood cells, white blood cells, and/or platelets. MDS may cause headaches, shortness of breath, fatigue, an increased risk of infections and bleeding, and bruising. We diagnose MDS by studying the results of blood and bone marrow tests and treat it using a stem cell transplant or medications. Learn more about MDS care at Memorial Sloan Kettering.