Werner Syndrome Essay Research Paper AbstractNowadays those

Werner Syndrome Essay, Research Paper

Abstract:

Nowadays those involved in aging research view aging in terms of a genetic disease rather than as a natural, evolution-driven process by which the old make way for the young. A condition of aged friends and relatives seems terrible to conceive; they are afflicted with a ghastly wasting disease, a plague whose effects are inescapable because of our own genes. People plagued with Werner syndrome do not even have the opportunity to experience this natural progression we call aging, instead this disease causes its victims to die of old age by their mid 40’s or 50’s.

Introduction:

Just about everyone dreads the physical decline often associated with aging, but people with the rare inherited disease known as Werner syndrome have to face the aging process far sooner than most. Unexpectedly, while they are still in their early twenties, their hair grays, their skin loses its suppleness, and their vision clouds from cataracts. Even worse, they get cancer, heart disease, and a host of other diseases that usually don’t strike until later in life. Most people afflicted with Werner syndrome die before age 50. Aging experts have long wondered just what kind of molecular defect could cause such a striking acceleration of the aging process.

Werner Syndrome is a rare progressive disorder that is characterized by the appearance of unusually accelerated aging. Although the disorder is typically recognized by the third or fourth decades of life, certain characteristic findings are present beginning during childhood, adolescence, and early adulthood (as seen in the picture below).

Werner Syndrome may also be characterized by development of a distinctive high pitched voice; eye abnormalities, including premature clouding of the lenses of the eyes due to aging; and certain endocrine defects, such as impaired functioning of the ovaries in females or testes in males or abnormal production of the hormone insulin by the pancreas and resistance to the effects of insulin. In addition, individuals with Werner Syndrome develop progressive thickening and loss of elasticity of artery walls. Some affected individuals may also be susceptible to developing certain tumors. Progressive arteriosclerosis, malignancies, and associated abnormalities may result in potentially life-threatening complications by approximately the fourth or firth decade of life due to Werner syndrome.

Discussion:

Just recently, an international team of geneticists, led by Gerard Schellenberg of the Veterans Affairs Puget Sound Health Care System in Seattle, discovered the gene at fault in Werner syndrome. Aging experts are already delighted by this magnificent finding. This is important because it is the first time that any gene that has been associated with aging has been identified. One reason for the excitement is that the structure of the protein encoded by the gene indicates that it is a helicase, an enzyme that acts to unwind DNA and sometimes RNA in order to facilitate such processes as the replication, repair, transcription, and recombination of DNA. Some helicases may also be important in ensuring the accuracy of chromosomal segregation. Precisely which subset of these functions is critical in producing the pathology of Werner syndrome is not yet known. This suggests that the mutations that cause Werner Syndrome may exert their harmful effects by upsetting one or another of those activities. The fact that these helicase mutations are responsible for the disorder, leads support to several lines of evidence that indicate that the somatic cells of Werner Syndrome patients are especially prone to mutations. By testing out what does happen, researchers hope they will eventually be able to design a treatment that slows the aging process and cures Werner syndrome.

The gene may also yield insights into cancer, because Werner syndrome patients suffer from many forms of cancer or rare tumors. From this, it can be concluded that the Werner syndrome gene is not only an aging gene, but also a cancer gene.

Schellenberg says he began looking for the Werner syndrome gene in 1992. At that point, Makoto Goto from Tokyo Metropolitan Otsuka Hospital and his colleagues had already shown that the gene is located on the short arm of chromosome 8 by genetic linkage studies-comparing the inheritance of the disease with that of markers at known locations on the chromosomes. To continue the hunt, scientists began by doing further genetic studies aimed at narrowing down the gene’s location. He then wanted to sequence DNA from the suspect region and scan the sequence to find likely genes. “My philosophy was to bring all the different gene identification technologies to bear [on this problem],” he recalls.

Other groups were also searching for the gene and a remarkable spirit of cooperation between competing groups aided the hunt. A team of American scientists and that of rival gene-hunter Tetsuro Miki of Osaka University Medical School shared tissue samples from affected families in order to improve each other’s chances of pinning down the gene’s location. Schellenberg credits the additional families and subjects with helping his team to narrow the search to a section of chromosome encompassing just a million bases-still a lot of DNA, but manageable for the detailed sequencing effort that followed.

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