Spinal muscular atrophy (SMA) is a progressive neuromuscular disease characterised by weakness of the muscles in the shoulders, hips, thighs and upper back. It may also weaken the muscles used for breathing and swallowing.¹

SMA results from mutations in the SMN1 gene on chromosome 5q.¹ These mutations cause a shortage of a protein called survival motor neuron (SMN), which results in the loss of nerve cells in the spine.¹

SMA is a clinical spectrum of disease with disease severity linked to fewer numbers of SMN2 gene copies and younger age of symptom onset.¹