Spinal muscular atrophy (SMA) is an inherited disorder that causes muscle wasting (atrophy), muscle weakness, and loss of movement. Symptoms may include weakness in the limbs; movement problems, such as difficulty walking; tremors; swallowing problems; and breathing difficulties.
The most severe type of SMA affects babies less than 6 months old and is usually fatal within the first few years. The least severe type begins in early adulthood, tends to cause relatively mild symptoms, and does not affect life expectancy. There is no cure for SMA.
Treatment is aimed at managing the symptoms.