The primary objective of this study is to investigate the natural history of spinal muscular atrophy (SMA) types 2 and 3 patients in Taiwan. This study will provide further insights into the clinical course SMA. Several analyses will be conducted regarding overall survival, demographic characteristics, motor function, respiratory and nutritional support, and genotype and phenotype correlation.

As with other rare diseases, individual groups of SMA have therefore opted to share patient information in the form of clinical sites to increase the overall patient cohorts on which clinical outcomes and new assisted-healthcare technologies can be assessed. Using the collaborative and retrospective study of types 2 and 3 SMA patients in Taiwan, the investigators aim to 1) characterize the correlation of genotype and phenotype, 2) correlate the onset, progression, management with disease outcome, 3) depict comorbidity and within type 2 and 3 SMA patients with different SMN2 copy number.

Inclusion Criteria:

1. Patients are diagnosed with SMA types 2 or 3
2. Generalized hypotonia and muscle weakness, weakness of the legs is greater than the arms, and the proximal part is weaker than distal part of extremities.
3. SMN1 gene deletion or mutation and/or neurogenic changes in electromyogram and/or muscle pathology.

Exclusion Criteria:

1. Non-5q SMA (no deletion or mutation of SMN1 gene) patients.
2. Type 1 SMA patients.

In the past decades, The SMA is a rare disease (incidence of 1 in every 6,000-10,000 live births) with a carrier frequency of about 1 in 40-50 people. Therefore, individual countries have small cohorts of affected patients.

There is not a plan to make IPD available