Relating Genetic and Environmental Risk Scores to Multiple Sclerosis Susceptibility

Background: \- Research shows that both genes and the environment influence a person s risk for getting multiple sclerosis (MS). However, it is not possible to accurately predict who will develop MS. Researchers want to study people with MS and their family members. They have developed a Genetic and Environmental Risk Score for MS. This score combines information from a person's medical history and genes. It also includes environmental factors that may be related to developing MS. This study will test this risk score to see if it can help predict who will develop MS. Objectives: \- To evaluate a score for genetic and environmental risk factors that may help predict whether a person will develop MS. Eligibility: * Individuals at least 18 years of age who have MS. * Individuals between 18 to 50 years of age who are the parent, brother, sister, or child of a person with MS. Design: * People with MS will allow researchers to look at their personal and medical data. These data will have been collected in other MS-related studies. * Relatives of people with MS will fill out a questionnaire and give blood and saliva samples. They will fill out the questionnaire again one year later. * Some relatives will have additional optional testing. These tests will include a physical exam and imaging studies. There may also be other tests. These tests may be repeated every 1 to 5 years for 20 years.