“5q-associated spinal muscular atrophy (SMA) is a rare monogenic lower motor neuron disease caused by mutations in the telomeric survival of motor neuron 1 (SMN1) gene leading to insufficient SMN protein levels. Lack of SMN protein predominantly leads to degeneration of lower motor neurons with consecutive progressive muscle wasting. In 2017, European Medicines Agency (EMA) approved the antisense oligonucleotide nusinersen as the first disease-modifying drug for SMA. Therefore, it is indispensable to investigate real-world evidence of treatment effects. Recently published observational studies showed satisfying motor score changes during nusinersen treatment. However, objective biomarkers are required to monitor disease progression and/or response to treatment: both creatine kinase (CK) and creatinine (CRN) are part of the muscle energy metabolism and are affected in neuromuscular diseases as they reflect muscle integrity and muscle mass. Few articles in the literature study the level and changes in plasma values of muscle enzymes in SMA 5q.
In our work we evaluate a possible correlation over time, from before the start of therapy to the present, between serum CK and CRN values and patients’ scores on motor scales (Hammersmith Functional Motor Scale Expanded). In detail, our patient cohort is as follows: 5 pediatric patients (3 with SMA type 2 and 2 with SMA type 3) and 4 adult patients with SMA type 3. All patients access our institute every 4 months to receive intrathecal administration of nusinersen. The study aim is to assess a possible correlation between clinical and laboratory results and their dynamics during nusinersen treatment.”