Loss of muscle mass, also called muscle wasting or atrophy, can happen gradually as part of getting older or more suddenly due to underlying medical conditions. Other factors can contribute, like ...

Distal spinal muscular atrophy (DSMA) is a rare genetic disease that causes a loss of muscle movement. It affects muscles further away from the center of the body, such as the hands, feet, and legs.

Werdnig Hoffmann disease is a form of spinal muscular atrophy. It affects the nerves that control voluntary movement in the body and can make it difficult to stand, walk, and sit, among other issues.