HLA-DQ4
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HLA-DQ4
(MHC Class II, DQ cell surface antigen) |
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| Illustration of HLA-DQ with gliadin peptide in the binding pocket. | |||
| Cis-haplotype | Haplotype | ||
| isoform, | subtype | DQA1 | DQB1 |
| DQ α3β4.1 | DQ4.3a | *0303 | *0401 |
| DQ α3β4.2 | DQ4.3b | *0303 | *0402 |
| DQ α4β4.2 | DQ4.2 | *0401 | *0402 |
HLA-DQ4 (DQ4) is a serotype subgroup within HLA-DQ(DQ) serotypes. The serotype is determined by the antibody recognition of β4 subset of DQ β-chains. The β-chain of DQ is encoded by HLA-DQB1 locus and DQ4 are encoded by the HLA-DQB1*04 allele group. This group currently contains 2 common alleles, DQB1*0401 and DQB1*0402. HLA-DQ4 and HLA-DQB1*04 are almost synonymous in meaning. DQ4 β-chains combine with α-chains, encoded by genetically linked HLA-DQA1 alleles, to form the - isoforms. These isoforms, nicknamed DQ4.3 and DQ4.4, are also encoded by the DQA1*0303 and DQA1*0401 genes, respectively.
DQA1*0303:DQB1*0401 is linked to DRB1*0405 and is common on the west Pacific rim, from Indonesia to Japan and inland areas of Eastern Asia. In Japan it confers susceptibility to juvenile diabetes likely via the DR4 gene.
DQA1*0303:DQB1*0402 is primarily found in Northeastern Asia and the west Pacific rim. It is similar to DQA1*0303:DQB1*0402.
DQB1*0401:DQB1*0402 has a trimodal global distribution. The highest frequencies are found in the highland regions of the new world, peaking in NW Mexico and in the Andes. It is also found at high levels in Namibia and Botswana. Between these two population it is moderatedly high in the Ainu of northern Japan.
DQ4 is associated with:
The DR8-DQ4 haplotype is associated with
DR4-DQ4(DRB1*0405:DQB1*0401) is associated with:
The DQA1*0303:DQB1*04 haplotype is associated with:
Other diseases mentioned are high altitude pulmonary edema, Vogt-Koyanagi-Harada syndrome (DRB1*0405, see above table for Japanese), HIV resistance in the US, and haemophilia A(anti-FVIII inhibitor response).
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Wikipedia