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The medical genetics of Jews is the study, screening, and treatment of genetic disorders more common in particular Jewish populations than in the population as a whole.〔 The genetics of Ashkenazi Jews have been particularly well-studied, resulting in the discovery of many genetic disorders associated with this ethnic group. In contrast, the medical genetics of Sephardic Jews and Mizrahi Jews are more complicated, since they are more genetically diverse and consequently no genetic disorders are more common in these groups as a whole; instead, they tend to have the genetic diseases common in their various countries of origin.〔 Several organizations, such as Dor Yeshorim, offer screening for Ashkenazi genetic diseases, and these screening programs have had a significant impact, in particular by reducing the number of cases of Tay–Sachs disease. ==Genetics of Jewish populations== Different ethnic groups tend to suffer from different rates of hereditary diseases, with some being more common, and some less common. Hereditary diseases, particularly hemophilia, were recognized early in Jewish history, even being described in the Talmud.〔 However, the scientific study of hereditary disease in Jewish populations was initially hindered by scientific racism, which believed in racial supremacism. However, modern studies on the genetics of particular ethnic groups have the tightly defined purpose of avoiding the birth of children with genetic diseases, or identifying people at particular risk of developing a disease in the future.〔 Consequently, the Jewish community has been very supportive of modern genetic testing programs, although this unusually high degree of cooperation has raised concerns that it might lead to the false perception that Jews are more susceptible to genetic diseases than other groups of people. However, most populations contain hundreds of alleles that could potentially cause disease and most people are heterozygotes for one or two recessive alleles that would be lethal in a homozygote. Although the overall frequency of disease-causing alleles does not vary much between populations, the practice of consanguineous marriage (marriage between second cousins or closer relatives) is common in some Jewish communities, which produces a small increase in the number of children with congenital defects. According to Daphna Birenbaum Carmeli at the University of Haifa, Jewish populations have been studied more thoroughly than most other human populations because:〔 * Geneticists are intrinsically interested in Jewish populations as a disproportionate percentage of genetics researchers are Jewish. Israel in particular has become an international center of such research. * Jewish populations, and particularly the large Ashkenazi Jewish population, are ideal for such research studies, because they exhibit a high degree of endogamy, and at the same time are a large group. * Jewish populations are overwhelmingly urban, and are concentrated near biomedical centers where such research has been carried out. Such research is especially easy to carry out in Israel, where cradle-to-grave medical insurance is available, together with universal screening for genetic disease. * Jewish communities are comparatively well informed about genetics research, and have been supportive of community efforts to study and prevent genetic diseases. * Participation of Jewish scientists and support from the Jewish community alleviates ethical concerns that sometimes hinder such genetic studies in other ethnic groups. The result is a form of ascertainment bias. This has sometimes created an impression that Jews are more susceptible to genetic disease than other populations. Carmeli writes, "Jews are over-represented in human genetic literature, particularly in mutation-related contexts." Another factor that may aid genetic research in this community is that Jewish culture results in excellent medical care, which is coupled to a strong interest in the community's history and demography. This set of advantages have led to Ashkenazi Jews in particular being used in many genetic studies, not just in the study of genetic diseases. For example, a series of publications on Ashkenazi centenarians established their longevity was strongly inherited and associated with lower rates of age-related diseases. This "healthy aging" phenotype may be due to higher levels of telomerase in these individuals. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Medical genetics of Jews」の詳細全文を読む スポンサード リンク
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