INFORMATION ON FRIEDREICH’S ATAXIA

Friedreich's ataxia (fa) is an inborn disorder, progressive nervous system disorder causing loss of balance and coordination.

CAUSES OF FRIEDREICH’S ATAXIA
The gene for fa codes for a protein called frataxin. Normal frataxin is found in the cellular energy structures known as mitochondria, where it is thought to be involved in regulating the transport of iron. In fa, the frataxin gene on chromosome 9 is long-drawn-out with nonsense information known as a "triple repeat." this additional dna interferes with normal production of frataxin, thereby impairing iron transport. Usually, there are 10-21 repeats of the frataxin gene. In fa, this sequence may be repeated between 200-900 times. The types of symptoms and severity of fa seems to be connected with the number of repetitions. Patients with more copies have more severe symptomatology. Researchers are still wrestling with how frataxin and the repeats on chromosome 9 are involved in causing fa. One theory recommends that fa develops in part because defects in iron transport prevent competent use of cellular energy supplies.

The nerve cells most exaggerated by fa are those in the spinal cord involved in relaying information between muscles and the brain. Tight control of movement requires complex feedback between the muscles promoting a movement, those limiting it, and the brain. Without this control, movements become ungraceful, jerky, and inappropriate to the desired action.

SYMPTOMS OF FRIEDREICH’S ATAXIA

Symptoms of fa generally first appear between the ages of 8 and 15. The first symptom is usually steps in coordination. A child with fa may graze doorways when passing through, for instance, or trip over low obstacles. Instability when standing still and deterioration of position sense is common. Foot deformities and walking up off the heels often results from uneven muscle weakness in the legs. Muscle spasms and cramps can take place, especially at night.

Ataxia in the arms follows, generally within several years, leading to reduce hand-eye coordination. Arm weakness does not usually occur until much later. Speech and swallowing difficulties are frequent. Diabetes mellitus may also occur. Nystagmus, or eye tremor, is common, along with some loss of visual acuity. Hearing loss may also occur. A side-to-side curvature of the spine (scoliosis) occurs in many cases, and may become severe.

Heartbeat abnormalities occur in about two thirds of fa patients, leading to shortness of breath after physical exertion, swelling in the lower limbs, and regular complaints of cold feet.

TREATMENT OF FRIEDREICH’S ATAXIA

There is no cure for fa, nor any treatment that can slow its growth. Amantadine can provide some limited improvement in ataxic symptoms, but is not recommended in patients with cardiac abnormalities.