Spinal Muscular Atrophy 1 (SMA1)
Spinal muscular atrophy is a genetic disorder that affects the control of muscle movement. It is caused by a loss of specialized nerve cells, called motor neurons, in the spinal cord and the part of the brain that is connected to the spinal cord (the brainstem). The loss of motor neurons leads to weakness and wasting (atrophy) of muscles used for activities such as crawling, walking, sitting up, and controlling head movement. In severe cases of spinal muscular atrophy, the muscles used for breathing and swallowing are affected. There are many types of spinal muscular atrophy, largely differentiated by the pattern of features, severity of muscle weakness, and age when the muscle problems begin.
Spinal muscular atrophy Type I , also called Werdnig-Hoffman disease, is the most severe form of the disorder that is evident at birth or within the first few months of life. Affected infants are developmentally delayed. Most are unable to support their head or sit unassisted. Children with Type I have breathing and swallowing problems that may lead to choking or gagging.
For more information, visit the Muscular Dystrophy Association website’s SMA page.