Friedreich's ataxia is a rare disease passed down through families (inherited) that affects the muscles and heart.
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.
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.
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