Friedreich's ataxia is a rare disease passed down through families (inherited) that affects the muscles and heart.
Causes, incidence, and risk factors
Friedreich's ataxia is caused by a defect in a gene called Frataxin (FXN), which is located on chromosome 9. Changes in this gene cause the body to produce too much of part of DNA called trinucleotide repeat (GAA). Normally, the body contains about 8 to 30 copies of GAA. Those with Individuals with Friedreich's ataxia have as many as 1,000 copies. The more copies of GAA a patient has, the earlier in life the disease starts and the faster it gets worse.
Friedreich's ataxia is an autosomal recessive genetic disorder. This means you must get a copy of the defective gene from both your mother and father.
About 1 in every 22,000-29,000 develop this disease. Family history of the condition raises your risk.
Symptoms are caused by the wearing away of structures in areas of the brain and spinal cord that control coordination, muscle movement, and some sensory functions. Symptoms generally begin in childhood before puberty, and may include:
Changes in vision, particularly color vision
Decrease in ability to feel vibrations in lower limbs
Tests of the heart may show a condition called hypertrophic cardiomyopathy in about 66% of persons with this condition.
Blood sugar (glucose) tests may reveal diabetes or glucose intolerance. An eye exam may show damage to the optic nerve, which usually occurs without symptoms.
Treatment for Friedreich's ataxia includes:
Walking aids or wheelchairs
Orthopedic interventions (such as braces) may be needed for scoliosis and foot problems. Treatment of heart disease and diabetes may help improve the quality and duration of life.
Friedreich's ataxia slowly gets worse and causes problems performing everyday activities. Most patients need to use a wheelchair within 15 years of the disease's start. The disease may lead to early death.
Individuals with a family history of Friedreich's ataxia who intend to have children should consider genetic screening and counseling to determine their risk.
Johnston MV. Movement disorders. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 597.
Kevin Sheth, MD, Department of Neurology, University of Maryland School of Medicine, Baltimore, MD. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.