Spinal Muscular Atrophy

Spinal muscular atrophy (SMA) is a genetic, progressive, and often terminal rare disease that affects an individual’s ability to walk, eat, and, ultimately, breathe. Debilitating and often fatal, SMA affects approximately one in 10,000 individuals and is the leading genetic cause of death among infants.

SMA impacts individuals across a range of ages – from infants and children to teens and adults – with varying levels of severity. The most severe form, infantile onset SMA (also known as Type 1), affects newborns and infants and can lead to paralysis and prevent infants from performing the basic functions of life, such as swallowing or holding up their heads. Later-onset SMA (Types 2 and 3) is most common among teens and adults, who may experience significant muscle weakness and disability, such as the inability to stand or walk independently.

Individuals with two copies of the SMN2 gene, the gene responsible for making the survival motor neuron (SMN) protein, are most likely to develop infantile-onset SMA, while those with three or four copies are most likely to develop later-onset SMA.


Biogen-85401    Date of preparation: December 2020