Nusinersen Improves Motor Function in Type 2 and 3 Spinal Muscular Atrophy Patients across Time

Abstract

Spinal muscular atrophy (SMA) is a genetic disorder primarily caused by mutations in the SMN1 gene, leading to motor neuron degeneration and muscle atrophy, affecting multiple organ systems. Nusinersen treatment targets gene expression and is expected to enhance the motor function of voluntary muscles in the limbs and trunk. Motor skills can be assessed through specific scales like the Revised Upper Limb Module Scale (RULM) and Hammersmith Functional Motor Scale Expanded (HFMSE). This study aims to evaluate the influence of nusinersen on the motor skills of patients with SMA Type 2 and 3 using real-world data collected over 54 months. A prospective longitudinal study was conducted on 37 SMA patients treated with nusinersen, analyzing data with R statistical software. The outcomes revealed significant improvements in motor functions, particularly in SMA Type 3 patients with higher RULM and HFSME scores. Additionally, GEE analysis identified time, type, age, and exon deletions as essential predictors of motor score improvements. The extended observation period is both a major strength and a limitation of this research, as the dropout rates could present challenges in interpretation. Variability in responses, influenced by genetic background, SMA type, and onset age, highlights the need for personalized treatment approaches.