Evolution of regional brain atrophy in children with multiple sclerosis

While multiple sclerosis (MS) has classically been considered to be a white matter disease, it is now clear that gray matter changes are seen at onset. Importantly, regional gray matter atrophy correlates strongly with motor outcomes in adult patients.¹ Individuals with pediatric-onset MS have greater disease burden, as evidenced by higher relapse rate² and increased lesion volume and atrophy on MRI³ than those with adult-onset MS. Furthermore, cognitive decline may be seen as early as 2 years after diagnosis in this population.⁴ Importantly, studies of structural correlates of disease progression in pediatric-onset MS must take the dynamic and maturational changes known to occur in the pediatric brain into account, including age- and sex-specific growth in some areas and regression and pruning in others.⁵ To this end, previous studies focused on white matter tracts and head size in pediatric-onset MS, and showed alterations in growth trajectories in patients with pediatric-onset MS in comparison with healthy youth.⁶ Others have demonstrated the extent of gray matter injury in the pediatric MS population, but have largely focused on specific deep gray matter structures.⁷ Much less is known about the dynamic pattern of growth and regression of various gray matter regions, and their relationship to outcomes in the pediatric patients with MS.