Autosomal recessive inheritance; prevalence is 2/100,000; GAA triplet repeat expansion found in first intron of X25 gene, located on chromosome 9q13-21, codes for conserved protein, frataxin; onset in early teen years; clinical symptoms include progressive gait ataxia, areflexia of lower limbs, impaired vibration and position sense, diffuse weakness, dysarthria, nystagmus, frequent Babinski sign, and hypertrophic cardiomyopathy; MRI is usually normal, may show mild cerebellar atrophy; most patients become non-ambulatory within 15 years of symptom onset; treatment is symptomatic (e.g., physical therapy), no specific treatment is available; antioxidants such as idebenone (a free radical scavenger), coenzyme Q10, or vitamin E are under investigation but of unclear clinical benefit; death from infection or cardiac disease occurs between 40 and 60 years of age.