What is Friedreich's Ataxia?
Friedreich's ataxia is a recessive inherited disease that causes progressive damage to the nervous system. Basically the brain sends signals via the nervous system which mixes up those signals to the muscles. Beginning symptoms include poor balance and coordination.
- Muscle weakness in the arms and legs
- Loss of coordination
- Vision impairment
- Hearing impairment
- Slurred speech
- High arches of the feet
- Heart disorders
However every Friedreich's Ataxia patient has different symptoms, it is 50% genetic and 50% environment. Usually, symptoms hit people young with progressive staggering or stumbling gait; and frequent falling, very similar to someone who is impaired. Legs are more severely involved. The symptoms are slow and progressive in Friedreich's Ataxia.
On average, after 10–15 years being affected by Friedreich's Ataxia, patients are usually wheelchair bound and require assistance with most routines of daily living.
The following physical signs may be noticeable on examination of Friedreich's Ataxia:
- Shaky eye movements, ataxia
- Absent tendon reflexes.
- Muscle weakness and slurred speech
- Loss of vibratory and sensation.
- Heart condition occurs in 91% of Friedreich's Ataxia patients, including cardiomyopathy.
Genetics of Friedreich's Ataxia
Friedreich's Ataxia (FA) is inherited in an autosomal recessive manner. Patients, with FA have two mutated or abnormal copies of the FXN gene, this means both parents must be a carrier of the disease for a child to be affected. It is estimated that 1 in 100 people are carriers, and carriers do not exhibit symptoms of Friedreich's Ataxia. Each such carrier parent has one mutated gene and one normal gene in the FXN gene. Because each child gets one of the mother’s genes and one of the father’s genes in this location, there are four possible combinations of the genes passed down to the child or a 25% chance that the child will have Friedreich's Ataxia.
The Friedreich's Ataxia gene mutation alters the production of a protein called frataxin. The mutant gene encodes the protein frataxin also called FXN which has expanded GAA triplet repeats. That put's an error in the coding of a Friedreich’s Ataxia patient. Frataxin is known to be an important protein that functions in the mitochondria (the energy-producing factories) of the cell. Frataxin helps to move iron and is involved with the formation of iron-sulfur clusters, which are necessary components in the function of the mitochondria and energy production. We also know that specific nerve cells degenerate in patients with Friedreich's Ataxia, and this is directly manifested in the symptoms of the disease. The exact role of frataxin in normal physiology remains unclear.
The Friedreich's Ataxia gene is located on chromosome 9.
Friedreich's ataxia Diagnosis
A diagnosis of Friedreich's ataxia requires a clinical examination including a medical history and a physical exam, in particular looking for balance difficulty, loss of proprioception, an absence of reflexes, and signs of neurological problems. Genetic testing now provides a decisive diagnosis.
Positive Friedreich's Ataxia genetic test results usually contain two numbers that indicate the presence of the disease.
What do these DNA triplet numbers mean?
Our genetic code is spelled out along the double helix of our DNA by triplet combinations of four nucleotides labeled A, T, C, and G. At the key place in the Friedreich's Ataxia gene of a person not affected with the disease, only a dozen or so triplet combinations of the nucleotides GAA would be found. In a Friedreich's Ataxia patient, however, this combination of the GAA nucleotides is usually repeated hundreds of times, making it very difficult for the code on the normal part of the gene to be read or "transcribed" and thus limiting the amount of Frataxin protein that can be encoded and formed. So, the two numbers in the genetic test reports refer to the number of GAA triplet repeats on the Friedreich's Ataxia gene. One number is associated with the gene inherited from mom and the other number is associated with the gene inherited from dad. The expanded numbers of the GAA triplet repeats confirm the inheritance of Friedreich's ataxia.
Research seems to indicate a general correlation between some Friedreich's Ataxia symptoms and the numbers of GAA repeats. These symptoms are not present in all individuals with, for example, diabetes occurs in about 10-20% of individuals with. The mental capabilities of people with Friedreich's ataxia remain completely intact. The progressive loss of coordination and muscle strength leads to motor incapacitation and the full-time use of a wheelchair. Most young people diagnosed with Friedreich's Ataxia require mobility aids such as a cane, walker, or wheelchair by their teens or early 20s.
Friedreich's Ataxia Treatment
There is no treatment or cure but FARA is working vigorously to change that! A Friedreich’s Ataxia patient will progress over the years and will require mobility aids such as,
These mobility aids are necessary to remain mobile and independent.
There is no certified treatment or cure for Friedreich’s Ataxia. In many cases, patients experience significant heart conditions along with mobility issues. Persons with Friedreich’s Ataxia may benefit from exercise and movement. Health professionals, such as physical therapists and occupational therapists, can prescribe an exercise program just for a Friedreich’s Ataxia patient. To help with gait and loss of proprioception, typically seen in patients with Friedreich’s Ataxia, along with other mobility issues and coordination difficulties.
In my many years of struggling with this mobility disorder I have found that diet and exercise can slow down the Friedreich's Ataxia progression. Strengthening and stretching exercises should also be incorporated to maintain muscle. Exercises should reflect daily tasks such as cooking, transfers and self-care. Along with muscle strength exercises, balance and coordination training should be developed to help minimize the progression. The more movement the better for all Friedreich’s Ataxia patients.