RNA biomarkers in spinal muscular atrophy: enhancing pathogenesis understanding and guiding precision medicine.

Spinal muscular atrophy (SMA) is a neurodegenerative disorder resulting from mutations in SMN1 that manifest as progressive muscle weakness and atrophy. Despite transformative therapies, such as nusinersen, risdiplam, and onasemnogene abeparvovec, heterogeneous patient responses underscore the need for reliable biomarkers to optimize treatment strategies. RNA biomarkers are particularly promising targets for monitoring SMA because the disease pathology is directly caused by impaired SMN protein, which is involved in RNA processing. Evidence suggests that SMN transcripts and specific microRNAs (i.e., miR-9, miR-206, and miR-132) are of significant diagnostic and prognostic value. In addition, specific microRNAs exhibit detectable changes in accessible biofluids at pre-symptomatic stages, enabling early non-invasive monitoring. Integration of global microRNA profiling (miRNome analysis) with clinical parameters has yielded SMA scores with high predictive value. Advancing RNA biomarker implementation requires several challenges to be addressed, including protocol standardization, validation in expanded patient cohorts, longitudinal evaluation, and seamless integration with clinical assessments. Emerging methodologies analyzing extracellular vesicle content and single-cell sequencing offer promising avenues for enhancing diagnostic precision. Multiparametric integration of RNA biomarkers may establish the foundation of precision medicine in SMA, potentially enabling individualized therapeutic selection based on molecular signatures to improve long-term patient outcomes.