Challenges in the classification of pediatric multiple sclerosis and future directions.

To improve care for children with multiple sclerosis (MS) and to advance understanding of the underlying biologic mechanisms through collaborative research studies, criteria for case definitions of pediatric MS and related CNS demyelinating disorders were proposed by the International Pediatric MS Study Group. Issues raised during development of these definitions and rationale behind criteria proposed are summarized in this article, as are potential international multicenter research studies that would be facilitated by the application of a uniform set of definitions.