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Friedreich’s ataxia (FA) is known as an autosomal recessive disease. This disease can develop only if a person inherits affected genes from each parent. If a person carries the disease they will have a recessive gene that will carry the genetic disorder like Friedreich’s ataxia. If a person is carrying the disease they will not actually have the disease but only carry it. Because they are carrying the gene, it will be passed on to their children. If the parents have the gene, the odds of their children carrying the gene are one out of two, and the odds of them actually having the disease are one out of four.
In the United States and Europe about one out of ninety people will carry the Friedreich’s ataxia gene. Each human has two copies of the gene, which are specifically placed on the individual’s chromosomes. The protein that is different in Friedreich’s ataxia gene is called frataxin. The defective gene is located on chromosome nine. The way the code is inherited, the sequence of bases is repeated too many times. A normal number of times the code would be repeated is 7 to 22 times, yet a person with Friedreich’s ataxia has the sequence repeated 800 to 1,000 times. The abnormality is called a triplet repeat expansion. The triplet repeat expansion is found in 98 percent of all the people with this disease, but it is not always present. The triplet repeat expansion disrupts the way the normal amino acids being turned into proteins. Studies have shown that without a normal level of frataxin that cells in the body cannot manage to handle the amount of oxidative stress, where the mitochondria is produced.
The disease causes the progressive damage of the nervous system, which results in symptoms that range from speech problems to muscle weakness to heart disease. This disease is named after the physician Nicholas Friedreich. He was one of the first people described to have the condition in the 1860’s. The word ataxia is related to the coordination problems, like being clumsy, awkward movements, or unsteadiness. The ataxia in this disease is the degeneration of the nerve tissue in the spinal cord and the nerves that control the muscle movements in the arms and legs. Because of the ataxia, the spinal cord becomes thinner and the nerve cells lose more of their myelin sheath. The myelin sheath is the insular that is a covering on all the nerve cells that conducts nerve impulses.
The symptoms could appear as early as 18 months or as late as 30 years. Normally the symptoms occur during 5 years of age to 15. One of the first symptoms can be seen in difficulty walking. Overall the ataxia will gradually get worse and spread to the arms and then to the trunk. Hearing loss has appeared to be a symptom in ten percent of people with Friedreich’s ataxia. Another early sign is deformities in the foot like hammertoes, foot inversion, clubfoot, and flexion of the toes. The symptoms in the eyes show as up as involuntary, rapid, rhythmic movements. A large percent of people with Friedreich’s ataxia will develop scoliosis. This curving of the spine to one side can possibly interfere with breathing if it is severe enough. Some of the other symptoms can be chest pain, heart palpitations, and shortness of breath. The diagnosis for Friedreich’s disease is done by a careful clinical examination, which consists of a physical exam and medical history. There may be several test performed including an EMG and genetic testing.
The progression of Friedreich’s ataxia is a slow one, the scientists have broken it down into two stages. These two stages are pretty simple: ambulatory, able to walk and nonambulatory, needing the assistance of a wheelchair. The first stage is shown by an absence or decrease in the muscle reflexes. When the heels are elevated and the toes flexed it becomes a foot deformity called Friedreich’s foot. During this time mild curvature of the spine may occur. Also, a reduction in the sense of touch in the legs and arms might occur. Towards the end of the ambulatory stage walking becomes much more difficult. Handwriting skills and manipulatory tasks can become even more difficult once the hands and arms are affected. The voice may be affected as well because of the lack of muscle control, along with the muscles in the eyes. When a person requires constant use of a wheelchair is when they have entered the nonambulatory stage, mainly around the thirties. The muscle weakness continues to get worse and it can become difficult to sit upright. In the later stage there is little movement in the legs and the arms become worse as well.
There are many things that become extremely important for a person with Friedreich’s ataxia to do along with their family. First, the person should go to a physician or neurologist who has a complete understanding of the complications of Friedreich’s, and have a complete examination. The person may need to have a neurological exam and other tests to rule out any other complications. These other tests should include an eye exam, a hearing test, evaluation by an orthopedist, an EKG, as well as an evaluation by an endocrinologist. If there symptoms get worse later on they may need to see a physical therapist, urologist, or even a speech pathologist. Genetic counseling is also recommended for the patient and family, to answer any questions and to see if they are carrying and passing on the gene.
Friedreich’s ataxia is a disease that progress into the nervous system. Usually after 15 to 20 years of having Friedreich’s disease a person is in a wheelchair, even later the person may become completely incapacitated. People who do have Friedreich’s ataxia are more likely to die in the early stages of adulthood. People who have symptoms that are not very severe live for much longer. There are no current effective cures for Friedreich’s ataxia. Research is always being done, and there is hope for a cure in the future. But in the mean time a person with the disease can live with their disabilities; even though there may be limitations there are still things that can be done despite these limitations.
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