Spinal muscle atrophy (SMA) is a serious heritable condition characterized by the loss of motor neurons, or nerve cells responsible for carrying instructions from the brain to the muscles to control their movement. SMA is divided into types based on the age of onset of the.
Keep in mind that every child or adult who has SMA will have a different experience. No matter how much your child's movement is limited, the.
Adult SMA, or SMA type 4, is rare. It begins after the age of 21 years. The person will have mild to moderate proximal weakness, which means.