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HLA A30-Cw5-B18-DR3-DQ2 (A30::DQ2) is a multigene haplotype that extends across a majority of the major histocompatibility complex on human chromosome 6. A multigene haplotype is a set of inherited alleles covering several genes, or gene-alleles. Long haplotypes, like A30::DQ2, are generally the result of descent by common ancestry. As haplotypes increase in size, Chromosomal recombination fragments them in a generation dependent process. A30::DQ2 can be written in an extended form covering the major histocompatibility loci as follows: HLA AThere are several composite haplotypes, A30-Cw5-B18 and a variant A30-CBL-B18 comprise A30::B18, there is also the B18-DR3 component and the HLA DR3-DQ2.5. Other haplotypes such as Cw5-B16-DR3 or B8-DR3-DQ2.5 have been presented in the literature. A dozen inflammatory diseases of the immune system can attribute some risk to the haplotype. Some disease like ''coeliac'' disease primarily ''associate'' with certain genes. While other diseases, like type 1 diabetes may have several, highly different, genes that attribute risk. Still other diseases, like ''myasthenia gravis'' have undetermined linkage to the haplotype. Haplotypes of A30-B18 or Cw5-B18 have been studied (see allelefrequencies.net and IHWC 1991). Despite that large areas of Northern Africa have not been studies by HLA, A30::DQ2 appears to have originate southwest of is current mode in Sardinia. observed that the haplotype is of likely paleo North African origin, and later studies of North Africa support that finding. Northern Iberians share with Sardinians a high frequency of the haplotype. However, there are some differences, linkage disequilibrium in Sardinians is highest whereas the Basque haplotype frequently has a different Cw allele indicating different origin for the haplotype. ==Distribution== The full haplotype has a fairly contained distribution, from Sardinia to the Northern Spain, to Southern Spain, Morocco, and to Tunisia. Trace amounts of A30-B18-DR3 can be found in Germany, Italy.〔 However, in the case of the Germans the Cw allele was not typed so it is undetermined whether the haplotype is of the 'Basque' variant or the ancestral 'Sardinian' type, In addition in Sardinia the A30 serotype has never been resolved by high resolution genetyping and therefore the A *3002 has not been confirmed. Cw5-B18 The Cw5-B18 (Cw *0501:B *1801) appears to be the oldest portion of the haplotype, as it is found below the sahel in the rainforest dwelling peoples of Cameroon and it is also found in the Nikoholo Mandenka. The second is not enlightening on its origin since there appears to be more recent geneflow between the Mandenka and the Tuareg Berbers. Studies of Rimaibe, Fulbe of Burkino Faso did not reveal the haplotype and many areas of West Africa have not been studied for CwB haplotypes. The CwB haplotype peaks in Sardinia along with the rest of the haplotype and can be found in high resolution studies of the S. Irish, N. Irish, UK Caucasoids, French. Many older studies did not have the resolution to detect the haplotype below a frequency of 1 percent, but a variety of evidence suggests that it declines to the northeast to trace levels.(See Table-below and Map-right) B18-DR3 The B-DR component shows a similar distribution, but lacks adequate testing to the south to resolve its most southern extent. DR3-DQ2 is very common in West and North Africa. And B18 is also elevated in N. Africa and Middle East, with peak levels in Italy. However B18 found in the Middle East is linked to B18-DR11 (DR11 is very common in the Eastern Mediterranean). The level of B18-DR3 peaks in Sardinia and but is also very high in the Basque of Northern Spain. This is one area of Europe where the B18-DR3 level is relatively different from Cw5-B18, as it appears there was a rare recombination event in the evolution of Cw5-B18-DR3 that lead to the replacement of Cw *0501 with Cw *1201. This might have occurred in northwest Iberia. Sardinia lacks this recombinant. Levels of B18-DR3 in Europe appear to be combinations of the Cw *0501 and Cw *1201 haplotype and for instance Albania has significant levels of B18-DR3 but lacks Cw5-B18 is significant quantities. In the Dutch and German populations B-DR haplotypes have undergone more intense studies allowing the detection of haplotypes to very low frequencies (0.25% in the Dutch and 0.05% in the Germans) consequently the edge of B18-DR3 haplotype in Europe is evident. Areas where typing lacks resolution are Austria, Slovakia, Czech republic, Etc. The levels in these regions may be higher as the level in Switzerland was detected in early studies.(See Table-left and Map-left) DR3-DQ2 The DR3-DQ2 component is not uncommon in Europe, it is shared by the northwest European ancestral haplotype AH8.1 and also appears within certain European groups with the Afro-Central Asia haplotype A33-B58. A30-B18 Areas in which CwB is low or untyped may contain A30-B18. For example, an early study of the Swiss indicated a haplotype frequency level of 1 percent. A30-B18 has been detected in a number of studies in Africa, however in East Africa the Cw allele *0501 (Cw5) is replaced by Cw7 in Kenya and Cw2 in the Sudanese. A30-B18 is found from Senegal to Morocco as far north as the French, a recent study of French departments found that A30-B18 is found in every department in France, indicating it has a more ancient distribution in the region. It is also found in Germans below 1 percent. Because the haplotype is indifferent to Cw allele the level is high in the Basque of Northern Spain. A30-B18 frequencies at trace levels may not indicate a common origin with A30::DQ2, Two alleles are found of A30 in Europe, A *3001 and A *3002, neither are common, but A *3002 is more common in Western Europe (attributed to the A30::DQ2 haplotype) A *3001 is common in India and to the East, and B18 is high in Italy, therefore random recombination will produce A30-B18 however, this may be of the haplotype A *3001-B18-DR11 haplotype. 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「A30-Cw5-B18-DR3-DQ2 (HLA Haplotype)」の詳細全文を読む スポンサード リンク
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