Patients with known or suspected genetic disorders in certain categories, such as those involving chromosomal or metabolic abnormalities, immune system or blood disorders, abnormal growth, benign tumors, and others may be eligible for this study. Participants will be interviewed by specialists in genetics about their condition and family history. They may also be asked to have a physical examination and certain tests needed for study of the specific individual's condition. These may include collection of blood samples (up to 3 tablespoons); imaging studies, such as computerized tomography (CT), magnetic resonance imaging (MRI), ultrasound and echocardiography; skin biopsy (removal of a small sample of skin tissue under local anesthetic), and other procedures. DNA testing may reveal the genetic abnormality responsible for the disorder. Participants who so wish will have an opportunity to talk with experts about the health implications of the test results.