Friedreich’s ataxia is a very rare inherited disease that causes progressive damage to the nervous system. Ataxia refers to coordination problems and unsteadiness. Friedreich’s ataxia causes degeneration of neurons in the spinal cord that control movement, as well as the sensory nerves that assist coordination. In later stages, additional cell injury can develop in the heart and pancreas.
Causes
The cause of Friedreich’s ataxia is a mutation in the frataxin gene, which is located on chromosome 9q13. To develop this disease, a person must inherit a copy of the defective gene from each parent, an autosommal recessive inheritance.
Risk Factors
There are no environmental risk factors; the disease is inherited.
Symptoms
Symptoms may vary. The following list describes the most common symptoms.
Early Symptoms:
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Age of onset: over the age of 25, usually in the early teenage years
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Progressive leg weakness presenting as difficulty walking
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Ataxia – incoordination and imbalance affecting limbs and gait
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Impaired sensation – especially "position sense" in the feet
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Loss of tendon reflexes in the legs
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As the disease progresses, in addition to nervous system involvement, heart failure and diabetes develop
Late Symptoms:
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Difficulty speaking and swallowing – decreased coordination of the tongue
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Loss of tendon reflexes in all limbs
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Atrophy of muscles
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Scoliosis – curving of spine (affects 85% of people with this condition)
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Foot deformities
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Foot ulcers
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Confined to a wheelchair (over 95% of those affected, by age 45)
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Hearing loss and or vision loss (over 10% of those affected)
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Eye movement abnormalities
Diagnosis
Your doctor will ask about your symptoms, including medical history, family history, and medications. Your doctor will also perform a physical exam. If this disorder is suspected, you may also see a neurologist, a specialist in the diagnosis and treatment of diseases involving the nervous system.
Tests may include the following:
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Electromyography and Nerve Conduction Studies – to assess the function of the muscles and nerves
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Computerized Tomography or Magnetic Resonance Imaging (MRI) – structural imaging of the brain and spinal cord
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Electrocardiogram and 24-hour Holter Monitoring – to assess the electrical activity of the heart
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Echocardiogram – a test that uses high-frequency sound waves (ultrasound) to examine the size, shape, and motion of the heart
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Genetic testing for the frataxin gene
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Blood (diabetic testing) and urine tests
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Sural nerve biopsy
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Genetic testing
Treatment
There is no known cure for Friedreich's ataxia.
Long-term management is aimed at maximizing function and controlling symptoms:
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Physical therapy and rehabilitation to cope with muscle weakness
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Use of orthotics for stability and weakness
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Surgery for correcting foot abnormalities and spinal scoliosis
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Periodic testing for associated conditions of diabetes and cardiomyopathy
As the exact role of frataxin is clarified, several theoretical treatments may emerge. Current studies are ongoing to assess a role for antioxidants, coenzyme Q10, and vitamin E.
RESOURCES:
Friedreich’s Ataxia Research Alliance
http://www.faresearchalliance.org
Genetic Alliance
http://www.geneticalliance.org
National Ataxia Foundation
http://www.ataxia.org
National Organization for Rare Disorders
http://www.rarediseases.org
CANADIAN RESOURCES:
Friedreich’s Ataxia
Muscular Dystrophy Canada
http://www.muscle.ca/
Ataxia Support Groups in Canada
International Network of Ataxia Friends
http://internaf.org
References:
Bradley WG, Daroff RB. Neurology in Clinical Practice. Philadelphia, PA: Butterworth Heinemann; 2004.
Friedreich’s ataxia. National Library of Medicine website. Available at: http://www.nlm.nih.gov/medlineplus/ency/article/001411.htm. Accessed September 12, 2005.
Friedreich’s ataxia fact sheet. National Institute of Neurological Disorders and Stroke website. Available at: http://www.ninds.nih.gov/disorders/friedreichs_ataxia/detail_friedreichs_ataxia.htm. Accessed September 12, 2005.
