Spinal muscular atrophy (SMA) is a genetic disease that attacks nerve cells, called motor neurons, in the spinal cord. These cells communicate with your voluntary muscles - the ones you can control, like in your arms and legs. As the neurons die, the muscles weaken. This can affect walking, crawling, breathing, swallowing, and head and neck control.

SMA runs in families. Parents usually have no symptoms, but still carry the gene. Genetic counseling is important if the disease runs in your family.

There are many types of SMA. Some of them are fatal. Some people have a normal life expectancy. It depends on the type and how it affects breathing. There is no cure. Treatments help with symptoms and prevent complications. They may include machines to help with breathing, nutritional support, physical therapy, and medicines.

NIH: National Institute of Neurological Disorders and Stroke