Cause and Effects of Amyotrophic Lateral Sclerosis
Jeremy Michaelson

Amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig's disease, is a chronic progressive motor neuron disease with a poor prognosis which eventually weakens and paralyzes the respiratory muscles. ALS can strike anyone. It generally occurs between the ages of 20 and 90, with the incidence normally increasing with age and peaking in the 60's and 70's. ALS causes its victims to get weaker and weaker until they are completely paralyzed. Amyotrophic lateral sclerosis attacks motor neurons of the brain which convey messages throughout the body. When muscles do not receive these messages they become weak and wither from lack of use, and as a result the patient becomes paralyzed.
ALS may be present for some time before noticeable symptoms occur. The initial signs and symptoms are usually dependent upon which muscles weaken first. Early symptoms usually begin with alpha motor neuron involvement and then progress to include cortical motor neuron involvement (Tidwell, pg 337-42). Patients may begin tripping or falling, some lose the dexterity in their hands and legs, and others find it difficult or near impossible to swallow or breathe. Gradual weakening of muscles causes the disease to go unnoticed for an extended period of time before visible symptoms become a concern. As a result of this latent period, nearly all victims in one way or another are handicapped when they become informed of having ALS. As the disease continues to progress all voluntary muscles become useless, restricting the individual from being able to move, eat, communicate, or breathe without the assistance of a respirator. Involvement of the respiratory system is inevitable and leads to respiratory failure, the usual cause of death in this disorder. Treatment consists of preventing respiratory complications and supporting lung function for as long as possible. In the slim instance that the patient survives long enough for the disease to run its full course, usually results in the person succumbing to complete paralysis.
ALS is not known to be a genetically linked disease, and generally strikes people with no history of the disease in their families. Still there has been approximately 5% of the patients who have had other family members with ALS. Recent experiments dealing with genetic analyses of patients with a familial, chromosome 21-linked form of ALS suggests that mutations in the cytosolic copper/zinc superoxide dismutase (SOD1) gene is somehow linked to the development of amyotrophic lateral sclerosis. Even though they have been unable to identify any functional disturbances of SOD1 activity, it is believed that altered free radical protection may be a leading contributor to the destruction of motor neurons (Nutrition Reviews, pg.243-245). Mutations in the human Cu/Zn SOD1 gene has been discovered in 20% of kindred with familial ALS, and similar findings have linked a specific SOD1 mutation with alterations in the neural cytoskeleton of patients with ALS (Tu, pg.3155-3160). It is these mutations in the SOD1 gene that injures nerve cells by enhancing the ability of its encoded enzyme to act as a peroxidase. A peroxidase oxidizes and damages lipids, leading to a degeneration of the cell membrane and eventually nerve cell death (Marx, pg.446-447). Plans to test antioxidants as a possible preventative and therapeutic procedure for patients with ALS are in the near future.
The cause of Amyotrophic Lateral Sclerosis is unknown. Presently ALS is incurable, and only symptomatic treatment is available. There are currently several major controversies concerning the possible role of immunological factors, genetic factors, environmental toxins, and viral infection in pathogenesis. These concepts must be considered in relation to what is known about the disease in all its aspects, including epidemiological data, information on the pathology of the disease, as well as the associated involvement of other systems (Swash, pg.4-16). Scientists have been seeking a cause and a cure for amyotrophic lateral sclerosis for more than 100 years. Only when all this information is assimilated can full understanding of the disease, and hopefully a logical approach to treatment and prevention, be achieved.

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Mutations in the copper-and zinc-containing superoxide dismutase gene are associated with "Lou Gehrig's disease." (1993, August). Nutrition Reviews, 51, 243-245.
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Tidwell, J. (1993). Pulmonary management of the ALS patient. Journal of Neuroscience Nursing, 25, 337-342.
Tu, Pang-Hsien., Raju, P., Robinson, K., Gurney, M. (1996, April 2). Transgenic mice carrying a human mutant superoxide dismutase transgene develop neuronal cytoskeletal pathology resembling human amyotrophic lateral sclerosis lesions. Proceedings of the National Academy of Sciences of the United States of America, 93, 3155-3160.

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