This is a retrospective cross-sectional observational study to characterize the clinical and epidemiological profile of patients with spinal muscular atrophy (SMA) 5q types II and III, in follow-up at the Brazilian Unified Public Health System (SUS). This study aims to provide baseline data, which in the future may be used by the Brazilian Ministry of Health (MS) to assess the effectiveness of nusinersen, as recommended in a risk sharing agreement established between MS and the pharmaceutical company that produces Spiranza (nusinersen). The clinical and epidemiological data will be collected from patients medical records, such as the score for the Hammersmith Functional Motor Scale - Expanded (HFMSE) and the Revised Upper Limb Module (RULM) at baseline, the WHO motor milestones at baseline, disease duration, age at the time of disease diagnosis, age at the time of disease screening, SMN2 (gene copy number), history of hospitalizations, history and characterization of previous surgical procedures, treatment dosage used, patient caregivers profile (ie, a family member or companion, who is responsible for taking care of the patient for most of the time). Other variables of interest that will also be collected are patients age and gender, geographic distribution, attending physician expertise and care structure where the patients were treated. The data acquisition will be performed using a paper and eletronic CRF (Case report Form). Written informed consent will be obtained from patients who meet the study elegibility criteria. The study will be performed in Brazilian public hospitals (centers) that are able to provide the treatment with nusinersen under the SUS scope. The total sample of patients and number of participating centers will be defined by the MS - SCTIE (Secretariat of Science, Technology and Strategic Supplies)/ DECIT (Department of Science and Technology). However, the initial estimation is a sample of 100 patients to be included in 10-15 centers.