Spinal muscular atrophy (SMA) is an autosomal recessive disorder characterized by degeneration of motor neurons in the spinal cord and caused by mutations of the survival motor neuron 1 (SMN1) gene.

The investigators will conduct a systematic review of the contents and activities collected via a comprehensive case report form. Patients who fulfilled diagnostic criteria for SMA type 1 will be reviewed retrospectively.

The primary objective of this study is to investigate the natural history of patients with spinal muscular atrophy (SMA) type 1 in Taiwan. This study will provide further insights into the clinical course and pathogenesis of SMA. Several analyses will be conducted regarding overall survival, respiratory support, feeding and nutritional support. The following outcome variables will be examined: correlation between SMA genotype and phenotype, survival, age of onset, and age of confirmed diagnosis, proportion of patients using non-invasive and invasive respiratory support, time to first use of respiratory support, proportion of patients on permanent ventilation, and time to permanent ventilation, number and average duration of hospitalizations, proportion of patients with gastrostomy, number of non-serious and serious respiratory infections, trend of growth parameter (e.g., body weight).

Inclusion Criteria:

• Jan. 1979~ 30 Jun. 2014 diagnosed with Spinal Muscular Atrophy (SMA)Type 1
• Onset of paralytic floppy infant less than 6 months of age
• Generalized hypotonia and symmetric weakness, which weakness is more severe in proximal than distal part of extremities
• Weakness in the legs is greater than in the arms
• Tendon reflexes are absent
• Neurogenic changes in electromyogram and/or muscle pathology
• SMN1 gene deletion or mutation

Exclusion Criteria:

• Non-5q SMA (no deletion or mutation of SMN1 gene)
• SMA type 2, type 3 or type 4 (onset of SMA after 6 months of age)

Spinal muscular atrophy Type 1