This National Institutes of Health website focuses on rare diseases, which are also called orphan diseases. The FAQs section in the About ORDR link states that a rare disease is a "disease or condition affecting fewer than 200,000 persons in the United States. An estimated 25 to 30 million people in the United States have a rare disease." Visitors will find that the information on this website is suitable for patients, health practitioners, researchers, caregivers, students and anyone interested in rare diseases. The Rare Diseases News tab near the top of the homepage contains such pertinent news as, "NIH Announces Genetic Testing Registry," "Undiagnosed Diseases Program Now Accepting New Applications," and "ORDR Announces Workshop on Natural History Studies of Rare Diseases." Visitors interested in participating in clinical trials should check out the tab Research and Clinical Trials, where there are over a dozen federal and non-federal web resources that have materials on such matters.