Risdiplam and nusinersen in spinal muscular atrophy: a descriptive real-world study on motor function outcomes in northwestern Iran

Abstract

Spinal muscular atrophy (SMA) types 2 and 3 are chronic neuromuscular disorders characterized by progressive motor impairment. Although disease-modifying therapies such as risdiplam and nusinersen have shown clinical efficacy, real-world data in pediatric populations remain limited. This prospective observational study evaluated motor function outcomes in 20 children with SMA (aged 3 to 13 years; 12 with type 2, 8 with type 3) receiving either risdiplam or nusinersen in Northwestern Iran. Motor function was assessed at baseline, 2 weeks, 1 month, and 6 months using the Hammersmith Functional Motor Scale-Expanded (HFMSE) and the Revised Upper Limb Module (RULM). Both treatments were associated with significant improvements in motor function during the 6-month follow-up. In the risdiplam group, HFMSE scores significantly increased at 1 and 6 months, while RULM scores improved at all time points. In the nusinersen group, HFMSE scores improved consistently at all assessments, whereas RULM scores showed minimal change. Nerve conduction parameters remained stable, and no adverse events were reported. These findings suggest that both risdiplam and nusinersen enhance motor function in children with SMA, with risdiplam providing notable benefits in upper limb function. Long-term, comparative studies are warranted to optimize individualized treatment strategies.