This study will evaluate the effects of Aubagio on changes in the brain using MRI.

Patients who take Aubagio will have an MRI, eye test, have blood taken, and complete a questionnaire on environmental risk factors to evaluate changes in the brain and on disease progression. A healthy control group will also complete the same testing regimen.

Inclusion Criteria:

• Subjects aged 18-65
• Clinically definite MS according to the Polman criteria, 52
• Relapsing MS or Healthy Control (no neurological disorders)
• Expanded Disability Status Scale (EDSS) scores ≤5.5
• Disease duration <30 years
• Normal kidney function (creatinine clearance >59 mL/min) (patients only)
• Signed informed consent
• None of the exclusion criteria

Exclusion Criteria:

• MS patients with hepatic impairment
• Nursing mothers or pregnant women who will need to undergo 12 months follow-up
• Women of childbearing potential not using reliable contraception
• Patients currently treated with leflunomide
• Serum alanine aminotransferase (ALT) >1.5 times the upper limit of normal
• A clinically significant infectious or neurological (for HC only) illness (e.g., cellulitis, abscess, pneumonia, septicemia) within 30 days prior to treatment assignment
• Unwillingness or inability to comply with the requirements of this protocol including the presence of any condition (physical, mental, or social) that is likely to affect the subject's ability to comply with the study protocol
• Any other reasons that, in the opinion of the Investigator, indicate that the subject is unsuitable for enrollment into this study
• Other pathology related to MRI abnormalities

MS patients from the Baird MS Center, The Jacobs Neurological Institute, Department of Neurology, State University at Buffalo, NY, USA who are also taking Aubagio as their disease modifying therapy.

Healthy controls from the general population.