Childhood multiple sclerosis: clinical features and recent developments on treatment choices and outcomes

Multiple sclerosis (MS) is an inflammatory idiopathic autoimmune disease causing demyelination of central nervous system (CNS). The incidence of pediatric MS is relatively rare, affecting 0.2 to 0.64/100,000 subjects; cases with MS onset before age 10-12 years, account for less than 1% of all MS cases, while 2.7 to 10.5% of all MS cases worldwide are seen in children <18 years of age, with a strong female preponderance. The disease course of MS varies from a benign type with relatively low level of disability after a long duration (15 years) of the disease, to a malignant type of MS with severe disability or even death within few months following onset. Diagnostic criteria for pediatric MS include ≥ 2 clinical events involving more areas of CNS inflammation in the absence of encephalopathy, separated by > 30 days, along with the involvement of brainstem. Pediatric MS generally presents relapsing-remittent form of MS, with majority of the patients recovering from the first attack. Major histocompatibility complex, more specifically, mutations in the human leukocyte antigen (HLA) DRB1*15 allele, are considered most important genetic factors that are contributory to the disease. Treatment choices for pediatric MS include many disease-modifying therapies (DMT) that are currently being used for adult MS and these are interferon-β 1a/1b (IFN-β1a/1b), glatiramer acetate, teriflunomide, dimethyl fumarate, alemtuzumab, etc. However, most of these have not gone through complete testing in randomized, placebo-controlled clinical trials for pediatric MS and are being prescribed off-label by clinicians. As these studies are progressing, it is important to address if these approaches of treating pediatric MS patients have any long-term impact on patients, in particular, physical, cognitive, developmental and social outcomes of the children.