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Friedreich ataxia

Central nervous sy...Central nervous system and peripheral nervous system

Friedreich's ataxia; Spinocerebellar degeneration

Definition

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

Causes

Friedreich ataxia is caused by a defect in a gene called frataxin (FXN). Changes in this gene cause the body to make too much of a part of DNA called trinucleotide repeat (GAA). Normally, the body contains about 8 to 30 copies of GAA. People with Friedreich ataxia have as many as 1,000 copies. The more copies of GAA a person has, the earlier in life the disease starts and the faster it gets worse.

Friedreich ataxia is an autosomal recessive genetic disorder. This means you must get a copy of the defective gene from both your mother and father.

Symptoms

Symptoms are caused by the wearing away of structures in areas of the brain and spinal cord that control coordination, muscle movement, and other functions. Symptoms most often begin before puberty. Symptoms may include:

Abnormal speech
Changes in vision, particularly color vision
Decrease in ability to feel vibrations in lower limbs
Foot problems, such as hammer toe and high arches
Hearing loss, this occurs in about 10% of people
Jerky eye movements
Loss of coordination and balance, which leads to frequent falls
Muscle weakness
No reflexes in the legs
Unsteady gait and uncoordinated movements (ataxia), which gets worse with time

Muscle problems lead to changes in the spine. This may result in scoliosis or kyphoscoliosis.

Heart disease most often develops and may lead to heart failure. Heart failure or dysrhythmias that do not respond to treatment may result in death. Diabetes may develop in later stages of the disease.

Exams and Tests

The following tests may be done:

ECG
Electrophysiological studies
EMG (electromyography)
Genetic testing
Nerve conduction tests
Muscle biopsy
X-ray, CT scan, or MRI of the head
X-ray of the chest
X-ray of the spine

Blood sugar (glucose) tests may show diabetes or glucose intolerance. An eye exam may show damage to the optic nerve, which most often occurs without symptoms.

Treatment

Treatment for Friedreich ataxia includes:

Counseling
Speech therapy
Physical therapy
Walking aids or wheelchairs

Orthopedic devices (braces) may be needed for scoliosis and foot problems. Treating heart disease and diabetes help people live longer and improve their quality of life.

Outlook (Prognosis)

Friedreich ataxia slowly gets worse and causes problems doing everyday activities. Most people need to use a wheelchair within 15 years of the disease's start. The disease may lead to early death.

Possible Complications

Complications may include:

Diabetes
Heart failure or heart disease
Loss of ability to move around

When to Contact a Medical Professional

Contact your health care provider if symptoms of Friedreich ataxia occur, especially if there is a family history of the disorder.

Prevention

People with a family history of Friedreich ataxia who intend to have children may want to consider genetic screening to determine their risk.

References

Mink JW. Movement disorders. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 615.

Warner WC, Sawyer JR. Neuromuscular disorders. In: Azar FM, Beaty JH, eds. Campbell's Operative Orthopaedics. 14th ed. Philadelphia, PA: Elsevier; 2021:chap 35.

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Review Date: 10/31/2022

Reviewed By: Neil K. Kaneshiro, MD, MHA, Clinical Professor of Pediatrics, University of Washington School of Medicine, Seattle, WA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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