Patients will talk with two genetics specialists who will explain the study and its possible implications for the patient and family and answer questions. The patient's medical records will be reviewed, a personal and family history will be taken, and a physical examination will be done. Various other procedures that may be done include drawing up to 6 tablespoons of blood, some of which will be used for DNA (genetic) studies, X-rays, echocardiography (ultrasound of the heart), magnetic resonance imaging (MRI), eye examination, hearing test, sleep study, sperm analysis and skin biopsy (surgical removal of a small piece of skin done under local anesthetic). There may be additional evaluations by specialists in rheumatology, rehabilitation medicine and orthopedics. When the tests and examinations are completed (after 2 to 3 days), a doctor will discuss the results with the patient. Patients whose DNA studies show that a gene change is responsible for their disorder will meet with a genetics nurse or counselor to review the results, express their feelings and ask any questions they may have. Patients may be asked to return to NIH every 6 months to 2 years for continued follow-up. Medical management will be provided primarily by the patient's own physician.