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Some families or ethnic groups have a higher incidence of a certain disease than does the population as a whole. For example, individuals from Eastern European, Ashkenazi Jewish descent are at higher risk for carrying genes for rare conditions that occur much less frequently in populations from other parts of the world. As example, cystic fibrosis, the most common genetic disease in the caucasian population, is caused by hundreds of different mutations along the gene. Individual families may carry the same mutation as each other, but not as the rest of the population affected with the same genetic disease. Ashkenazi tested for CF test positive at a 97% occurrence rate.
Cystic fibrosis is a disease that affects the lungs and pancreas and is discovered in early childhood. It is the most common autosomal recessive genetic disease found in the caucasian population: one in 25 people of Northern European ancestry are carriers of a mutated cystic fibrosis gene. The gene, located on chromosome 7, was identified in 1989.
The gene mutation for cystic fibrosis is detected by a direct DNA test. Over 600 mutations of the cystic fibrosis gene have been found; each of these mutations cause the same disease. Tests are available for the most common mutations. Tests that check for the 86 of the most common mutations in the Caucasian population will detect 97% of carriers for cystic fibrosis. (The percentage of mutations detected varies according to the individual's ethnic background).
Tay-Sachs disease , also autosomal recessive, affects children primarily of Ashkenazi Jewish descent. Children with this disease die between the ages of two and five. This disease was previously detected by looking for a missing enzyme. The mutated gene has now been identified and can be detected using direct DNA mutation analysis.
Huntington disease is one example of a late-onset autosomal dominant disease. Its symptoms of mental confusion and abnormal body movements do not appear until middle to late adulthood. The chromosome location of the gene responsible for Huntington's chorea was located in 1983 after studying the DNA from a large Venezuelan family affected by the disease. Ten years later, the gene was identified. A test is now available to detect the presence of the expanded base pair sequence responsible for causing the disease. The presence of this expanded sequence means the person will develop the disease.
Another late onset disease, Alzheimer's, does not have as well a understood genetic cause as Huntington's disease. The specific genetic cause of Alzheimer disease is not as clear. Although many cases appear to be inherited in an autosomal dominant pattern, many cases exist as single incidents in a family. Like Huntington's, symptoms of mental deterioration first appear in adulthood. Genetic research has found an association between this disease and genes on four different chromosomes. The validity of looking for these genes in a person without symptoms or without family history of the disease is still being studied.
In 1994, a mutation linked to early-onset familial breast and ovarian cancer was identified. BRCA1 is located on chromosome 17. Women with a mutated form of this gene have an increased risk of developing breast and ovarian cancer. A second related gene, BRCA2, was later discovered. Located on chromosome 13, it also carries increased risk of breast and ovarian cancer. Although both genes are rare in the general population, they are slightly more common in women of Ashkenazi Jewish descent.
What are the other diseases?
Tay-Sachs Disease is a condition where children develop normally until about four to six months of age.It is at this time that the central nervous system begins to degenerate.Individuals with Tay-Sachs Disease lack an enzyme called hexosaminidase (Hex A).The child loses all motor skills and becomes blind, deaf and unresponsive.Death usually occurs by the age of four.The carrier rate in the Ashkenazi Jewish population is approximately 1 in 25.More rare than the infantile type is Late Onset Tay-Sachs Disease, where the progression of symptoms is slower and milder.
Canavan Disease is very similar to Tay-Sachs Disease, with normal development until age two to four months, followed by progressive loss of previously attained skills.Most individuals with Canavan Disease die by the age of five.An estimated 1 in 40 Ashkenazi Jews is a carrier for this disease.
Niemann-Pick Disease – Type A is a disease in which a harmful amount of a fatty substance accumulates in different parts of the body.Failure to thrive and a progressive neurodegenerative course lead to death by three years of age.The carrier rate in the Ashkenazi Jewish population is approximately 1 in 90.
Gaucher Disease – Type 1 (pronounced go-shay) is a variable condition, both in age of onset and in progression of symptoms.A painful, enlarged and overactive spleen, with anemia and low white blood cell count are usually the initial features of Gaucher Disease.Bone deterioration is a major cause of discomfort and disability.Approximately 1 in 14 Ashkenazi Jews is a carrier of this condition.Treatment is available.
Familial Dysautonomia (FD) is a disease that causes the autonomic and sensory nervous systems to malfunction.This affects the regulation of body temperature, blood pressure, stress response, normal swallowing and digestion.An estimated 1 in 30 Ashkenazi Jews is a carrier of FD.
Bloom Syndrome is characterized by short stature, sun-sensitive facial skin lesions, an increased susceptibility to infections and a higher incidence of leukemia and certain cancers.The carrier rate is about 1 in 100 in the Ashkenazi Jewish population.
Fanconi anemia – Type C is a disease associated with short stature, bone marrow failure and a predisposition to leukemia and other cancers.Some children may have learning difficulties or mental retardation.Approximately 1 in 89 Ashkenazi Jews is a carrier for this condition.
Mucolipidosis IV (ML IV) is caused by the accumulation of certain harmful substances throughout the body.Individuals with ML IV experience a range of levels of motor and mental retardation, with developmental delays often manifesting themselves as early as the first year of life.Other symptoms can be related to the eyes, such as corneal clouding, pseudostrabismus and retinal degeneration.
Cystic Fibrosis (CF) is a multi-system disorder that causes the body to produce a thick mucus.The mucus accumulates primarily in the lungs and the digestive tract, resulting in chronic lung infections and poor growth.CF does not affect intelligence.The carrier rate for CF among all Caucasian individuals is approximately 1 in 25.The CF carrier test has a detection rate of 97% in the Ashkenazi Jewish population.
Posts: 3595 | From: Moved To Mars. Waiting with shotgun | Registered: Dec 2006
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^ It explains why a great number of people are F'ed up and why assimilation at all costs is imperative.
Posts: 3595 | From: Moved To Mars. Waiting with shotgun | Registered: Dec 2006
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