Multiple system atrophy (MSA) is a degenerative neurological disorder. MSA is associated with the degeneration of nerve cells in specific areas of the brain. This cell degeneration causes problems with movement, balance, and autonomic functions of the body such as bladder control or blood-pressure regulation. The cause of MSA is unclear and no specific risk factors have been identified, although research indicates that a prion form of the alpha-synuclein protein may be the cause of the disease.