Pediatric-onset Multiple Sclerosis in Families: A Distinct Phenotype

Objective: Multiple sclerosis (MS) is a chronic, immune-mediated disease of the central nervous system.Pediatric-onset MS (POMS) represents a distinct subgroup with unique clinical and immunological features.Although familial predisposition contributes to MS pathogenesis, data on familial POMS remain limited.To investigate the demographic and clinical characteristics of familial POMS and compare them with those of the broader MS patient cohort. Materials and Methods:We performed a retrospective descriptive analysis of 3,411 patients diagnosed with MS at a university hospital MS center.Of these, 523 had a family history of MS, and 251 were identified as having POMS, defined as disease onset before age 18.Data on demographic and clinical characteristics, cerebrospinal fluid (CSF) findings, treatment history, and disability scores were analyzed using IBM SPSS version 25.Results: Among 3,411 MS patients, 251 (7.36%) had POMS.Of these, 177 (70.5%) were female and 74 (29.5%) were male.Most had a relapsingremitting course (236 patients, 94%), while 15 (6%) developed secondary progressive MS; no cases of primary progressive MS were identified.Within the 523 familial MS cases, 51 (9.75%) had POMS.CSF analysis was available for 31 patients, 24 (77.4%) of whom showed MS-specific abnormalities; 13 (41.9%)had an elevated IgG index.Regarding treatment history, 59 patients (23.5%) received first-line therapies, 123 (49%) second-line therapies, and 69 (27.5%) third-line therapies.The mean Expanded Disability Status Scale score was 1.3. Conclusion:This study adds to the literature on POMS by providing detailed demographic, clinical, and familial data.The findings underscore the importance of considering familial predisposition when evaluating pediatric MS and highlight the need for further research into the genetic and immunological mechanisms underlying POMS.Long-term follow-up and genetic studies are warranted to deepen understanding of this uncommon yet clinically important MS subtype.