Spinal Muscular Atrophy

Spinal Muscular Atrophy (SMA) is a progressive and often fatal muscle-wasting disorder that commonly affects infants and young children. SMA is caused by a genetic mutation that impairs the development and functioning of the nerves that control muscles. SMA is marked by progressive wasting of the skeletal muscles and an inability to control movement. Symptoms range from mild muscle weakness to partial or complete paralysis. The most common type of SMA is type 1 (also known as Werdnig-Hoffman disease or infantile-onset SMA). This form starts before an infant is 6 months old and is marked by floppy muscle weakness and poor motor control. Babies who have SMA type 1 may never be able to sit without support or hold up their heads. In some severe cases, infants may die before they are a year old. SMA is caused by a mutation in the survival motor neuron 1 (SMN1) gene which normally produces a protein that is responsible for maintaining healthy nerve cells. Without this protein, the muscles lack crucial signals to function and become weaker and smaller over time (hence the term “atrophy”). Treatment options for SMA vary depending on the severity and age of the person affected. Generally, treatments aim to improve muscle strength, maintain independence, and slow the progression of the disorder. These can include physical therapy, surgery, breathing aids, and medications. Although there is currently no cure for SMA, research continues to unlock new treatments and therapies to improve the prognosis and quality of life of those affected. In 2019, the FDA approved a gene therapy drug that increases the amount of the SMN1 protein, which may delay the onset and slow the progress of the disease.