Ataxia is a loss or lack of muscle coordination. In Friedreich ataxia, this symptom occurs early in life, usually between the ages of five and sixteen. It is the most common of the early-onset hereditary ataxias, occurring in 1 to 2 Caucasians per thousand. It is rarely found in people of African descent, and almost never in people of Asian descent. The disease is inherited in autosomal recessive fashion. The gene associated with this disorder is located on the long (q) arm of the ninth chromosome.

Symptoms include degeneration of certain sensory and motor pathways, and degeneration of some peripheral nerves. This results, at first, in difficulty walking. Eventually, the arms also become involved. The spine develops an extreme curvature. Certain reflexes, such as the knee-jerk and ankle-jerk, disappear. The legs lose their ability to sense vibration or their own position. There are problems with the joints. Muscles...