Inability to coordinate voluntary muscular movements.
In common usage, the term describes an unsteady gait. Hereditary ataxias are usually caused by degeneration of the spinal cord , cerebellum , or other parts of the nervous system . The most common is Friedreich ataxia, which begins at ages 3–5, progressing slowly to almost complete incapacity by age 20. There is no specific therapy. Metabolic disorders, brain injuries, and toxins can cause ataxia.