Spinal Muscular Atrophy (SMA)
About Spinal Muscular Atrophy (SMA)
Spinal muscular atrophy (SMA) is a hereditary disease that causes weakness and muscle wasting due to the loss of lower motor neurons that control movement1. This weakness and muscle wasting results from a lack of survival motor neuron (SMN) protein, which is critical for the maintenance of motor neurons. Ultimately, individuals with the most severe type of SMA can become paralysed and have difficulty performing the basic functions such as breathing and swallowing2.
SMA is estimated to occur in 1 in 6,000 to 1 in 10,000 live births3. Its severity correlates with the amount of SMN protein. People with Type 1 SMA, the most severe life-threatening form, produce very little SMN protein and don’t live beyond two years old without respiratory support. People with Type 2 and Type 3 SMA produce greater amounts of SMN protein and have less severe, but still life-altering forms of SMA2.
1. FDA approves first drug for spinal muscular atrophy,
FDA, Dec 2016.
2. U.S. FDA Approves Biogen’s SPINRAZA™ (nusinersen), The First Treatment for Spinal Muscular Atrophy,
Biogen, Dec 2016.
3. Spinal muscular atrophy,
D'Amico, A., et al., Orphanet Journal of Rare Diseases, 2011.