Friedreich's Ataxia

Wheelchairs in a hospital hallway. (Photo: pixabay.com)
People affected with ataxia often depend on a wheelchair for moving around.

Friedreich's Ataxia is a progressive hereditary disease that manifests gradually, normally before the age of twenty-five. The research community is working intensively to alleviate symptoms in order to improve the quality of life of affected people.

Ataxia: What does it mean?

The term ataxia comes from the Greek "he taxis" meaning order. The "A" prefix indicates a negative. Ataxia therefore means "without order" and is a general description of disturbance in movement coordination, i.e. in groups of muscles working together. This often results in an unsteady gait (ataxic gait) or lack of balance (static tremor) and lack of coordination in the fingers and feet.

There are different forms of ataxia

Friedreich's Ataxia (FA) is a spino-cerebellar ataxia, in other words a disturbance of motor function controlled by the spinal cord. This is due to the mutation of a specific gene. Friedrich's Ataxia is found in less than one in every 50,000 births

How does Friedreich's Ataxia progress?

In most cases, the onset of FA occurs before the age of 25. The progression of the disease is steady and insidious, starting with problems like lack of balance and slight standing and walking ataxias. For this very reason, FA is often not diagnosed for many years. Gradually, patients begin to experience an impaired sense of touch and deep sensibility (bathyesthesia) and are noticeable by their "penguin walk" or unsteady, shaky gait. There is a tendency to step out on the balls of the feet rather than on the heels. Later on, the problems extend to clumsiness and an uncertain grip.
The disease can remain stable for years. However, as it progresses it affects the central nervous system and the patient is forced to resort to a wheelchair.

What are the symptoms of Friedreich's Ataxia?

Other symptoms include impaired reflexes (hyporeflexia) and a loss of spatial awareness and sensation (temperature, touch, etc.), above all in the legs. The syndrome can be accompanied by a range of other symptoms, including deafness, twitching of the eye, foot deformity, curvature of the spine (scoliosis), permanently cold feet due to bad circulation, bladder problems, and difficult in swallowing. These can be complicated by enlargement of the heart muscle (cardiomyopathy) and diabetes. We would expressly point out, however, that the symptoms do not include any loss of mental faculty.

What causes Friedreich's Ataxia?

One cause of FA has been identified to be the overloading of the mitochondria with iron molecules. This produces highly reactive molecules (so-called "free radicals"), which cause destruction of the nerve cells. It is highly probable that a shortage of production in levels of the protein frataxin is responsible for this overloading. Frataxin is needed to eliminate free radicals from the mitochondria.

Is Friedrich's Ataxia hereditary?

Friedrich's Ataxia is caused by a recessive gene. In order for a recessively inherited disease to manifest, both of the chromosomes in a pair of chromosomes must be defective. If only one chromosome is defective, the illness does not develop, although it can be passed on. This means that it is possible for FA to be passed down through generations without the disorder ever appearing. When two carriers of the genetic trait have a child, there is a 25% chance (in each child) of it developing FA. One in eighty healthy people are carriers of the FA gene.

How is Friedreich's Ataxia treated?

Idebenone is a powerful antioxidant. That means it combats free radicals. Unfortunately, not enough of the active substance succeeds in entering the mitochondria, so its benefits are limited. But Idebenone is successful in combating one of the life-threatening symptoms of FA, the thickening of the heart wall (cardiomyopathy). However, Idebenone is very expensive, and requires a dosage of 5mg per kg of body weight. Mnesis is currently supported by German health insurers.

Current research: MitoQ

A new and much more promising drug is currently undergoing trials. MitoQ is basically the same substance but is attached to a cell neurotransmitter. Which means that a hundred times more of the active substance succeeds in entering the mitochrondria. This should lead to a more effective treatment. If all goes well, the drug should be on the market by 2006. A cure for FA is a long way off, but any slowing down of the disease's progression would be good news for sufferers and their relatives.

Author: Sandra Brühwiler

Edited and translated by PmcC - MyH

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