Background: The course and prognosis of childhood-onset multiple sclerosis have not been well described.
Methods: We used data from 13 adult neurology departments affiliated with the European Database for Multiple Sclerosis (EDMUS) network to identify a cohort of 394 patients who had multiple sclerosis with an onset at 16 years of age or younger and a comparison group of 1775 patients who had multiple sclerosis with an onset after 16 years of age. We determined the initial clinical features, the dates of disease onset, and the occurrence of outcomes, including relapse, conversion to secondary progression, and irreversible disability as measured by scores of 4 (limited walking ability but ability to walk more than 500 m without aid or rest), 6 (ability to walk with unilateral support no more than 100 m without rest), and 7 (ability to walk no more than 10 m without rest while using a wall or furniture for support) on the Kurtzke Disability Status Scale (range, 0 to 10; higher scores indicate more severe disability).
Results: For patients with childhood-onset multiple sclerosis, the estimated median time from onset to secondary progression was 28 years, and the median age at conversion to secondary progression was 41 years. The median times from onset to disability scores of 4, 6, and 7 were 20.0, 28.9, and 37.0 years, respectively, and the corresponding median ages were 34.6, 42.2, and 50.5 years. In comparison with patients with adult-onset disease, those with childhood-onset disease were more likely to be female than male (female:male ratio, 2.8 vs. 1.8), were more likely to have an exacerbating-remitting initial course (98% vs. 84%), took approximately 10 years longer to reach secondary progression and irreversible disability, and reached these landmarks at an age approximately 10 years younger (P<0.001 for all comparisons).
Conclusions: Patients with childhood-onset multiple sclerosis take longer to reach states of irreversible disability but do so at a younger age than patients with adult-onset multiple sclerosis.