Spinal Muscular Atrophy (SMA)

A progressive disease which causes degeneration of the spinal cord motor neurons.  The muscle wasting is often more prevalent in the legs than the arms, as well as the muscles used for walking, crawling, and control of the neck and head.  There are various types of SMA,  Werdnig Syndrome, or type 1, is the most severe.  Type 2 is intermediate, and Kugelberg-Welander disease, or type 3 is the mildest form.