Definition
Friedreich’s ataxia is a very rare inherited disease. It causes a gradual breakdown of the nervous system. Friedreich’s ataxia affects nerve in the spinal cord that control movement, and sensory nerves that help with coordination. In later stages, the disease can also cause injury to the heart and pancreas.
Causes
Friedreich’s ataxia is caused by a problem with a gene called the frataxin gene. This gene is found on chromosome 9q13. To develop this disease, a person must inherit a copy of the defective gene from each parent. However, there are some people with Friedreich’s ataxia that have no family history of the disorder.
Symptoms
Symptoms can be different for each person. The following list describes the most common symptoms:
Early Symptoms
- Present in people under the age of 25, usually in the early teenage years
- Progressive leg weakness (eg, difficulty walking)
- Ataxia—lack of coordination and imbalance affecting limbs and walking pattern
- Impaired sensation—especially "position sense" in the feet
- Loss of tendon reflexes in the legs
- Heart failure and diabetes develop as the disease progresses
Late Symptoms
- Difficulty speaking and swallowing—decreased coordination of the tongue
- Loss of tendon reflexes in all limbs
- Atrophy of muscles
- Scoliosis —curving of spine (affects 85% of people with this condition)
- Foot deformities
- Foot ulcers
- Confined to a wheelchair (by age 45, occurs in 95% of those affected)
- Hearing loss and/or vision loss (over 10% of those affected)
- Eye movement abnormalities
- Movement disorders (eg, tremor, dystonia, chorea)
Diagnosis
Your doctor will ask about your symptoms. You will also be asked about your medical history, family history, and current medication. A physical exam will be done. If Friedrich's ataxia is suspected, you may also see a doctor who specializes in the nervous system.
Tests may include:
- EMG and nerve conduction studies —a test to assess the function of the muscles and nerves
- Computerized tomography —a test that uses a computer to make cross-sectional images of the head and spinal cord
- MRI scan —a test that uses magnetic waves to make pictures of structures inside the brain and spinal cord
- Electrocardiogram and 24-hour holter monitoring —a test that assesses the electrical activity of the heart
- Echocardiogram —a test that uses high-frequency sound waves (ultrasound) to examine the size, shape, and motion of the heart
- Genetic testing for the frataxin gene
- Blood and urine tests
- Nerve or muscle biopsy
Treatment
There is no known cure for this condition.
Long-term management is aimed at maintaining as much function as possible and controlling symptoms. Some treatments that may help include:
- Physical therapy and rehabilitation to cope with muscle weakness
- Use of orthotics (devices that go in your shoes) to provide stability and to help with weakness
- Surgery for correcting foot abnormalities and scoliosis
- Periodic testing for associated conditions of diabetes and cardiomyopathy
The exact role of the protein frataxin is being studied. This may help to develop more treatment options. Studies are ongoing to assess the role of siderophores, a medicine which can lead to decreased iron accumulation in the body. Antioxidants, coenzyme Q 10 , histone deacetlyase inhibitors, erythropoietin, and vitamin E are also being reviewed for potential benefits.