Obesity and Pediatric Multiple Sclerosis

Pediatric MS subjects will meet below inclusion and exclusion criteria: Inclusion Criteria: * Ability to provide informed consent (or assent for minors) * Relapsing-remitting MS diagnosis per 2017 McDonald criteria * Ages ≥ 10 years to ≤ 20 years * Diagnosis of MS or first clinical symptom of MS (whichever comes first) within ≤ 36 months from the time of enrollment. Exclusion Criteria: * Progressive form of MS * Patients with an active, chronic disease of the immune system other than MS * Conditions affecting the central nervous system (CNS) white matter (e.g. leukodystrophy) or for whom another condition may better explain imaging abnormalities (e.g. lupus) * Myelin oligodendrocyte glycoprotein (MOG) antibodies on serologic testing * Corticosteroid exposure within 30 days of study enrollment Control subjects (Aim 2) will meet the below inclusion and exclusion criteria: Inclusion Criteria: * Ability to provide informed consent (or assent for minors) * Age-, sex-, \& BMI-matched to pediatric MS subjects (1:1 allocation) * Healthy children and young adults from the local communities Exclusion Criteria: * History of past imaging or neurologic event raising concern for any inflammatory CNS process * Medical history or previous/current diagnosis consistent with an autoimmune disorder pertaining to any system of the body (e.g. diabetes mellitus type 1, Crohn's disease, lupus)