The objective of the National Myelodysplastic Syndromes Natural History Study (The National MDS Study) Data Coordinating Center (DCC) is to provide overall coordination of The National MDS Study and provide all the necessary administrative, logistical, data management, and statistical support for the study. The National MDS Study is a seven-year observational study of 2000 adults newly diagnosed with MDS and up to 500 age-matched participants who are not diagnosed with MDS, but who are clinically suspected of having this syndrome.