Shy-Drager syndrome (SDS) is a sporadic, rare, progressive neurodegenerative disease characterized by features of parkinsonism, autonomic failure, and cerebellar or pyramidal dysfunction. Shy-Drager syndrome is also known as striatonigral degeneration, olivopontocerebellar atrophy, and multiple system atrophy.

In the United States, the frequency of SDS is about 2:100,000 to 15:100,000. The frequency in other countries varies considerably. Men are more likely to be stricken than women, by a 3:1 to 9:1 ratio. Disease onset typically occurs between the ages of 52 and 55 years. The disease progresses over a period of 1 to 18 years, with a mean survival of 6 to 9.5 years.

The cause of SDS is not known. There have been anecdotal suggestions of exposure to environmental toxins or trauma as causative agents, but none have been confirmed. Changes to the interomediolateral cell column have been documented as well as widespread brain anomalies. Neuronal losses have been documented in several brain regions.