Initial brain MRI characteristics of 41 children (<18 years) and 35 adults (>18 years) at multiple sclerosis (MS) onset were analyzed retrospectively in a study at UCSF Regional Pediatric and Adult MS Centers, and University of California, San Francisco. Children had a higher number of total T2- and large T2-bright areas than adults. Children more frequently had T2-bright foci in the posterior fossa and enhancing lesions than adults. Age was the main independent predictor for infratentorial involvement. 
COMMENT. Higher disease burden, posterior fossa involvement, and rate of new lesions in pediatric-onset MS are characteristics associated with worse disability progression in adults.