The effect of pharmacological therapy on the nutritional status and body composition of children with spinal muscular Atrophy: a systematic review

Background Spinal Muscular Atrophy (SMA) is a rare genetic neuromuscular disorder whose prognosis has significantly improved thanks to disease-modifying therapies (DMTs) such as nusinersen, risdiplam, and onasemnogene abeparvovec. However, their effects on nutritional status and body composition remain incompletely understood. Objective This systematic review aimed to critically evaluate current evidence regarding the effects of pharmacological therapies on nutrition and body composition in children and adolescents with SMA Types I, II and III. Methods This systematic review was conducted according to PRISMA 2020 guidelines. PubMed, Scopus, and Web of Science were searched from January 2021 to May 2026. Eligible studies included pediatric patients with SMA Types I–III treated with nusinersen, risdiplam, or onasemnogene abeparvovec and reporting nutritional or body composition outcomes. Methodological quality was evaluated using Joanna Briggs Institute (JBI) tools, and certainty of evidence was assessed using the GRADE framework. Results Nine studies involving 354 pediatric patients met the inclusion criteria. Nusinersen was associated with improvements in growth indicators and body composition parameters, particularly among ambulatory children. Onasemnogene abeparvovec appeared effective in preserving feeding autonomy when administered early, although established bulbar dysfunction often persisted despite treatment. Limited evidence suggested that risdiplam may provide additional benefit in swallowing function in selected patients previously treated with gene therapy. Overall certainty of evidence ranged from very low to moderate, mainly due to observational study design, heterogeneity of outcome measures, and small sample sizes. Conclusions Current evidence suggests that DMTs may positively influence selected nutritional and body composition outcomes in pediatric SMA. Nevertheless, persistent dysphagia and feeding difficulties remain common, particularly in severe phenotypes. Standardized nutritional assessment protocols and multidisciplinary management remain essential components of SMA care.