LAUSR

INTRODUCTION Pediatric-onset (PO) multiple sclerosis (MS) accounts for about 2-10% of the total MS cases. Recently, a greater attention has been given to POMS, with substantial improvements in the understanding of its pathophysiology, in the diagnostic work-up and in the identification of reliable prognosticators associated with long-term disability in these patients. AREAS COVERED This review summarizes the most recent updates regarding the pathophysiology of POMS, the current diagnostic criteria and the clinical, neuroradiological and laboratoristic markers that have been associated with disease progression (i.e., occurrence of a second clinical attack at disease onset and accumulation of disability in definite MS). EXPERT OPINION The study of POMS, where the clinical onset is closer to the biological onset of MS, may contribute to better understand how the different pathological processes impact brain maturation and contribute to disease progression, but also how brain plasticity may counterbalance structural damage accumulation. Although rare, POMS is a severe disease, characterized by a prominent clinical and radiological activity at disease onset and by the accumulation of physical and cognitive disability at a younger age compared to the adult counterpart, with significant detrimental consequences at long-term. Early and accurate diagnosis, together with early treatment, is highly warranted.