HLA-DQ7

{| id="drugInfoBox" style="float: right; clear: right; margin: 0 0 0.5em 1em; background: #ffffff;" class="toccolours" border=0 cellpadding=0 align=right width="240px" |- | align="center" colspan="2" | 250px|Illustration of HLA-DQ with peptide in the binding pocket |- | align="center" colspan="2" | <div style="font-size:medium; line-height:120%;">major histocompatibility complex, class II, DQ7 </div> |- | bgcolor="#e7dcc3" | Haplotypes | bgcolor="#eeeeee" | DQA1*03:02:DQB1*03:01 DQA1*03:03:DQB1*03:01 DQA1*04:01:DQB1*03:01 DQA1*05:05:DQB1*03:01 DQA1*06:01:DQB1*03:01 |- | colspan="2" bgcolor="#dddddd" | '''Structure''' (See HLA-DQ) |-style="background:#f8f8f8" | bgcolor="#dddddd" | '''Identifiers'''|| align="center" | <div style="font-size:medium; line-height:120%;">alpha 1 ''*0302'' ''*0303'' ''*0401'' ''*0505'' ''*0601''</div> |- | bgcolor="#e7dcc3" | Symbol(s) | bgcolor="#eeeeee" | [http://www.gene.ucl.ac.uk/nomenclature/data/get_data.php?hgnc_id=HGNC4942 HLA-DQA1]{{Dead link|date=January 2020 |bot=InternetArchiveBot |fix-attempted=yes }} |- | bgcolor="#e7dcc3" | EBI-HLA | bgcolor="#eeeeee" | [http://www.ebi.ac.uk/cgi-bin/imgt/hla/get_allele.cgi?DQA1*0302 DQA1*0302] |- | bgcolor="#e7dcc3" | EBI-HLA | bgcolor="#eeeeee" | [http://www.ebi.ac.uk/cgi-bin/imgt/hla/get_allele.cgi?DQA1*0303 DQA1*0303] |- | bgcolor="#e7dcc3" | EBI-HLA | bgcolor="#eeeeee" | [http://www.ebi.ac.uk/cgi-bin/imgt/hla/get_allele.cgi?DQA1*0401 DQA1*0401] |- | bgcolor="#e7dcc3" | EBI-HLA | bgcolor="#eeeeee" | [http://www.ebi.ac.uk/cgi-bin/imgt/hla/get_allele.cgi?DQA1*0505 DQA1*0505] |- | bgcolor="#e7dcc3" | EBI-HLA | bgcolor="#eeeeee" | [http://www.ebi.ac.uk/cgi-bin/imgt/hla/get_allele.cgi?DQA1*0601 DQA1*0601] |-style="background:#f8f8f8" | bgcolor="#dddddd" | '''Identifiers'''|| align="center" | <div style="font-size:medium; line-height:120%;">beta 1 ''*0301'' ''*0304''</div> |- | bgcolor="#e7dcc3" | Symbol(s) | bgcolor="#eeeeee" | HLA-DQB1 |- | bgcolor="#e7dcc3" | EBI-HLA | bgcolor="#eeeeee" | [http://www.ebi.ac.uk/cgi-bin/imgt/hla/get_allele.cgi?DQB1*0301 DQB1*0301] |- | bgcolor="#e7dcc3" | EBI-HLA | bgcolor="#eeeeee" | [http://www.ebi.ac.uk/cgi-bin/imgt/hla/get_allele.cgi?DQB1*0304 DQB1*0304] |- | colspan="2" bgcolor="#dddddd" | '''Shared data''' |- | bgcolor="#e7dcc3" | Locus | bgcolor="#eeeeee" | chr.6 ''[https://www.ncbi.nlm.nih.gov/Omim/getmap.cgi?chromosome=6p21.31 6p21.31]'' |- |}

'''HLA-DQ7''' ('''DQ7''') is an HLA-DQ serotype that recognizes the common HLA DQB1*0301<ref name="pmid7905469">{{cite journal |vauthors=Bunce M, Taylor CJ, Welsh KI | title = Rapid HLA-DQB typing by eight polymerase chain reaction amplifications with sequence-specific primers (PCR-SSP) | journal = Hum. Immunol. | volume = 37 | issue = 4 | pages = 201–6 | year = 1993 | pmid = 7905469 | doi =10.1016/0198-8859(93)90502-R }}</ref> and the less common HLA DQB1*0304 gene products. DQ7 is a form of 'split antigen' of the broad antigen group DQ3 which also contains DQ8 and DQ9.

DQ7 is linked by haplotype to a number of DQA1 (DQ alpha chain) genes, producing in cis-haplotype form, a large number of DQ αβ isoforms. These DQ alpha chains are also known to form transhaplotype isomers with other HLA-DQ.

DQ7 is linked to the following alpha chains genes (DQA1*) * 03 – *0301, *0302, *0303 * 0401 * 0505 * 0601

==Serology==

{| border="0" cellspacing="0" cellpadding="0" align="left" style="text-align:center; background:#ffffff; margin-right: 2em; border:2px #e0e0ff solid;" |+ DQ3, DQ7, DQ8, and DQ9 recognition of Some DRB1*and <ref>[https://www.ebi.ac.uk/imgt/hla/allele.html derived from IMGT/HLA]</ref> |- style="background:#f0f0ff" | style="width:60px" | DQB1* || style="width:60px" | '''DQ7''' | style="width:60px" | DQ3 || style="width:60px" | '''DQ8''' || style="width:60px" | Sample |- style="background:#f0f0ff" | allele || % || % || % || size (N) |- | style = "background:#e8e8f8" | 0301 || 85 || 40 || 1 || 12220 |- | style = "background:#e8e8f8" | 0304 || 40 || 35 || 8 || 111 |- |}

'''Serotyping efficiency'''. The serotyping efficiency of DQ7 toward DQB1*0301 is reasonably good, but still results in some false negatives, for *0304 the typing efficiency is poor and cross-reaction with DQ8 is relatively high.

==Alleles==

===DQB1*0301=== DQB1*0301 is the major DQ7 allele '''DQB1*0301''' appears to be associated with lupus anticoagulant.<ref name="pmid1673688">{{cite journal |vauthors=Arnett FC, Olsen ML, Anderson KL, Reveille JD | title = Molecular analysis of major histocompatibility complex alleles associated with the lupus anticoagulant | journal = J. Clin. Invest. | volume = 87 | issue = 5 | pages = 1490–5 | year = 1991 | pmid = 1673688 | doi =10.1172/JCI115158 | pmc = 295227 }}</ref>

===DQB1*0304=== DQB1*0304 is the minor DQ7 allele

==Haplotypes== {|border="0" cellspacing="0" cellpadding="1" align="left" style="text-align:center; margin-right: 1em; border:1px #ffeebb solid; background:#f8f6f8; " |+ '''HLA DQA1*03:DQB1*0301 frequencies''' |- style="background:#efe5ef" | || || freq |- style="background:#eee5ef" | ref. || align="left" |Population || (%) |- | <ref name = "pmid12753660"/> || align="left"|Chukotka Chukchi (Siberia) ||26.7 |- | <ref name = "pmid12753660"/> || align="left"|Chukotka Eskimos (Siberia)||25.0 |- | <ref name = "pmid12753660"/> || align="left"|Koryaks (NE Kamchatka, Siberia)||19.1 |- | <ref name = "pmid12753660"/> || align="left"|Polygus Evenks (Siberia)||11.4 |- | <ref name = "pmid12753660"/> || align="left"|Khalkh (Ulaanbaatar, Mongolia) ||11.0 |- | <ref name = "pmid12753660"/> || align="left"|Negidal (Siberia)||9.6 |- | <ref name = "pmid12753660"/> || align="left"|Kushun Buryat (Siberia) ||8.0 |- | <ref name = "pmid12753660"/> || align="left"|Tarialan Khoton (Mongolia) ||7.8 |- | <ref name = "pmid12753660"/> || align="left"|France Ceph||6.0 |- | <ref name = "pmid12753660"/> || align="left"|Russia Tuva (2)||6.0 |- | <ref name = "pmid12753660"/> || align="left"|Udegeys Gvaysugi (Siberia) ||4.8 |- | <ref name = "pmid12753660"/> || align="left"|Irkutsk Tofalar (Siberia )||4.7 |- | <ref name = "pmid12753660"/> || align="left"|Ulchi (Siberia)||4.1 |- | <ref name = "pmid12753660"/> || align="left"|Belgian pop2||4.1 |- | <ref name = "pmid12753660"/> || align="left"|England Caucasoid||4.0 |- | <ref name = "pmid12753660"/> || align="left"|Italy pop 2||2.8 |- | <ref name = "pmid12753660"/> || align="left"|Russia Tuva Todja||2.3 |- | <ref name = "pmid12753660"/> || align="left"|China Ürümqi Kazak||2.4 |- | <ref name = "pmid12753660"/> || align="left"|Sulamai Kets (Siberia)||2.3 |- | <ref name = "pmid12753660"/> || align="left"|Russia Siberia Nganasan Dudinka||2.1 |- | <ref name = "pmid12753660"/> || align="left"|NW Slavic Russia ||2.0 |- | <ref name = "pmid12753660"/> || align="left"|Japan Fukuoka||1.2 |- | <ref name = "pmid12753660"/> || align="left"|Japan (2)||1.1 |}

DQ haplotypes of this serotype are formed between the cis-chromosomal genes of the DQA1 locus. This includes DQA1*0301, *0302, *0303, *0401, *0505, *0601.

There is a rather large degree of disequilibration about DQA1*0301 suggesting that this is one of the older and more established HLA DQB1* alleles in Eurasia. The intron structure of DQB1 suggest that DQB1*0301 DQB1*0302/*0303 split occurred before DQB1*0302/*0303, the distribution of *03 in Africa suggest that recombination DQA1*03:DQB1*0301 are primarily the result of recombination events that have occurred in Africa. A recent study of ''myasthenia gravis'' in Houston confirms the presence of A*0505:B*0301 in Nigeria. B1*0301 and A1*03 haplotypes are found at relatively high frequencies in SE Asia and Austronesia, also indicating that it is well established in the exo-African population.

===DQ7.3=== The DQ7.3 haplotype can be formed by DQA1*0301:DQB1*0301, DQA1*0302:DQB1*0301, DQA1*0303:DQB1*0301. In the west, the DQA1*0303:DQB1*0301 haplotype appears to be more common. The gene products of all 3 function similarly and subunits are interchangeable. In the literature, older DNA tests recognize DQA1*0303 as DQA1*0302, and still oldest DNA tests recognize all three as DQA1*03 or DQA1*0301.

'''DQA1*0303:DQB1*0301''' may be involved in narcolepsy.<ref name="pmid17207713">{{cite journal |vauthors=Hong SC, Lin L, Lo B, etal | title = DQB1*0301 and DQB1*0601 modulate narcolepsy susceptibility in Koreans | journal = Hum. Immunol. | volume = 68 | issue = 1 | pages = 59–68 | year = 2007 | pmid = 17207713 | doi = 10.1016/j.humimm.2006.10.006}}</ref> DQ7.3 appears to be associated with oral ulcerations and gingival disease <ref>{{cite journal | pmid = 8052655 | volume=91 | issue=16 | title=Common major histocompatibility complex class II markers in clinical variants of cicatricial pemphigoid. | date=Aug 1994 | journal=Proc Natl Acad Sci U S A | pages=7747–51 | doi=10.1073/pnas.91.16.7747 | pmc=44479 | vauthors=Yunis JJ, Mobini N, Yunis EJ, Alper CA, Deulofeut R, Rodriguez A, Foster CS, Marcus-Bagley D, Good RA, Ahmed AR| bibcode=1994PNAS...91.7747Y | doi-access=free }}</ref>

===DQ7.4=== {|border="0" cellspacing="0" cellpadding="1" align="right" style="text-align:center; margin-left: 3em; border:1px #ffeebb solid; background:#f8f6f8; " |+ '''HLA DQA1*0401:DQB1*0301 ''' |- style="background:#efe5ef" | || || freq |- style="background:#eee5ef" | ref. || align="left" |Population || (%) |- | <ref name = "pmid12753660"/> || align="left"|Chukotka Chukchi (Siberia)||9.5 |- | <ref name = "pmid12753660"/> || align="left"|Gvaysugi Udegeys (Siberia)||9.5 |- | <ref name = "pmid12753660"/> || align="left"|Chukotka Eskimos (Siberia)||8.7 |- | <ref name = "pmid12753660"/> || align="left"|Polygus Evenks (Siberia)||7.2 |- | <ref name = "pmid12753660"/> || align="left"|NE Koryaks (Kamchatka) ||6.5 |- | <ref name = "pmid12753660"/> || align="left"|Cameroon Saa||4.4 |- | <ref name = "pmid12753660"/> || align="left"|Sulamai Kets (Siberia)||2.3 |- | <ref name = "pmid12753660"/> || align="left"|Gambia||1.4 |- | <ref name = "pmid12753660"/> || align="left"| Fukuoka Japan||1.2 |- | <ref name="pmid12974796">{{cite journal |vauthors=Klitz W, Maiers M, Spellman S, etal | title = New HLA haplotype frequency reference standards: high-resolution and large sample typing of HLA DR-DQ haplotypes in a sample of European Americans | journal = Tissue Antigens | volume = 62 | issue = 4 | pages = 296–307 | year = 2003 | pmid = 12974796 | doi =10.1034/j.1399-0039.2003.00103.x }}</ref> || align="left"|Caucasian Americans||0.3 |}

'''DQA1*0401:DQB1*0301''' (DQ7.4) This haplotype is found in Siberia, Africa but also at low levels in Western Europe.

===DQ7.5=== {|border="0" cellspacing="0" cellpadding="1" align="left" style="text-align:center; margin-right: 1em; margin-bottom: 2em; border:1px #ffeebb solid; background:#f8f6f8; " |+ '''HLA DQA1*0505 frequencies''' |- style="background:#efe5ef" | || || freq |- style="background:#eee5ef" | ref. || align="left" |Population || (%) |- | <ref name="pmid12753660">{{cite journal |vauthors=Middleton D, Menchaca L, Rood H, Komerofsky R | title = New allele frequency database | journal = Tissue Antigens | volume = 61 | issue = 5 | pages = 403–7 | year = 2003 | pmid = 12753660 | doi =10.1034/j.1399-0039.2003.00062.x | doi-access = free }}</ref>|| align="left"|Lebanon (estimated)||40.0 |- | <ref name = "pmid12753660"/> || align="left"|Italy Rome||29.6 |- | <ref name = "pmid12753660"/> || align="left"|Netherlands (2)||15.5 |- | <ref name = "pmid12753660"/> || align="left"|Tunisia||14.6 |- | <ref name = "pmid12753660"/> || align="left"|England (2)||10.1 |- | <ref name = "pmid12753660"/> || align="left"|South Korea||6.8 |- | <ref name = "pmid12753660"/> || align="left"|Congo Kinshasa Bantu||4.4 |} '''DQA1*<span style="color:purple;">0505</span>:DQB1*0301''' (DQ7.5) was gene-typed as '''DQA1*<span style="color:red;">0501</span>:DQB1*0301''' until it was recognized that there was amino acid sequence variant in the preprocessed DQA1* gene product (proto-α-chain polypeptide encoded DQA1*0505). This proto-alpha, once processed, is identical to the DQA1*0501 encoded α-chain once it is processed. Almost 100% of DQ7.5 haplotypes carry the DQA1*0505 allele.<ref name="pmid10777105">{{cite journal |vauthors=Pera C, Delfino L, Longo A, Pistillo MP, Ferrara GB | title = Novel associations among HLA-DQA1 and -DQB1 alleles, revealed by high-resolution sequence-based typing (SBT) | journal = Tissue Antigens | volume = 55 | issue = 3 | pages = 275–9 | year = 2000 | pmid = 10777105 | doi =10.1034/j.1399-0039.2000.550313.x | url = https://zenodo.org/record/1231460 }}</ref> The DR5-DQ7.5 is common in the Southeastern Europe and the Levant, with DQ7.5 reaching a haplotype frequency of 40% in Lebanon. Its high level is probably not by chance, the haplotype appears to protect against juvenile diabetes, which appears to be more common among cereal eating peoples.<ref name="pmid16988007">{{cite journal |vauthors=Almawi WY, Wakim-Ghorayeb SF, Arekat MR, etal | title = Association of selective HLA class II susceptibility-conferring and protective haplotypes with type 2 diabetes in patients from Bahrain and Lebanon | journal = Clin. Vaccine Immunol. | volume = 13 | issue = 11 | pages = 1296–8 | year = 2006 | pmid = 16988007 | doi = 10.1128/CVI.00206-06 | pmc = 1656545}}</ref> Cereals were first domesticated in the Near and Middle East more than 10,000 years ago and selection may explain DQ7.5's higher frequencies. (See: Triticeae)

The processed alpha subunit of DQA1*0505 is identical to that of DQA1*0501, but some slight differences in the association with autoimmune disease are observed, possibly as a result of linked DR and DQB1 genes. DQA1*0505 can play into celiac disease under two circumstances. First it can increase risk when DQ2.5 is present, although current studies indicate that it marginally increases risk relative to DQB1*0202 in DQ2.5 cis haplotype. DQA1*0505, without DQ2, is found in a small percentage of coeliac disease (without DQ2 or DQ8).<ref name="pmid12651074">{{cite journal |vauthors=Karell K, Louka AS, Moodie SJ, etal |title=HLA types in celiac disease patients not carrying the DQA1*05-DQB1*02 (DQ2) heterodimer: results from the European Genetics Cluster on Celiac Disease |journal=Hum. Immunol. |volume=64 |issue=4 |pages=469–77 |year=2003 |pmid=12651074 |doi= 10.1016/S0198-8859(03)00027-2}}</ref>

DQ7.5 is found also high in frequency in the new world, but with DR types less commonly encountered in the old world. DQA1*05 allele is not clear in the new world. DQB1*0301 may be under current positive selection in the human population, at least in areas where DQ2.5 and DQ8 are high, as it confers resistance to type 1 diabetes. For hepatitis type B, DQ7 is associated with persistence but for C, DQ7 is associated with clearance.<ref name="pmid17465466">{{cite journal |vauthors=Singh R, Kaul R, Kaul A, Khan K | title = A comparative review of HLA associations with hepatitis B and C viral infections across global populations | journal = World J. Gastroenterol. | volume = 13 | issue = 12 | pages = 1770–87 | year = 2007 | pmid = 17465466 | doi = 10.3748/wjg.v13.i12.1770| pmc = 4149952 | doi-access = free }}</ref> DQA1*0505, DQB1*0301 appear to increase the risk for melanoma in the Spanish population however this may have a linkage to more recent fair skinned migrants. DQB1*0301 is also associated with allergic fungal sinusitis, human papillomavirus (HPV) induced warts, limited cutaneous systemic sclerosis in Africans, and primary sclerosing cholangitis in Southern Europeans. DQB1*0301 is also predisposing in narcolepsy.<ref name="pmid17207713"/> DQB1*0301 does not to play a role in any frequently occurring autoimmune disease and its presence in the near east and suppressed frequencies of coeliac disease and Type 1 diabetes in these regions is suggestive that it has a positive selection in Post-Mesolithic cereal based societies in the Western Eurasia.

DQB1*0301 appears to be more associated with early onset myasthenia gravis in Japanese than DQ8, and was also found along with DQB1*0304 to be associated with Chinese MG. DQ7 or associated DR types may play a role in rheumatoid arthritis. In celiac disease the DQ7 (A*0505/1) can mediate celiac disease when HLA DQ2.2 is also present. HLA DQB1*0301 in Turks is associated with Thymoma but the risk may be associated with HLA class I loci.

===DQ7.6=== {|border="0" cellspacing="0" cellpadding="1" align="right" style="text-align:center; margin-left: 3em; border:1px #ffeebb solid; background:#f8f6f8; " |+ '''HLA DQA1*0601 frequencies''' |- style="background:#efe5ef" | || || freq |- style="background:#eee5ef" | ref. || align="left" |Population || (%) |- | <ref name = "pmid12753660"/> || align="left"|Java Yogyakarta||48.1 |- | <ref name = "pmid12753660"/> || align="left"|Kiribati||37.9 |- | <ref name = "pmid12753660"/> || align="left"|Nauru||28.4 |- | <ref name = "pmid12753660"/> || align="left"|Harbin City (Manchuria, China) ||12.8 |- | <ref name = "pmid12753660"/> || align="left"|Thailand||12.7 |- | <ref name = "pmid12753660"/> || align="left"|South Korean (5)||4.4 |- | <ref name = "pmid12753660"/> || align="left"|China Beijing and Xian||3.5 |- | <ref name = "pmid12753660"/> || align="left"|Japan||3.0 |- | <ref name = "pmid12753660"/> || align="left"|India Bombay||1.7 |- | <ref name = "pmid12753660"/> || align="left"|England Caucasoid||0.6 |- | <ref name = "pmid12753660"/> || align="left"|Italy Central||0.6 |- | <ref name = "pmid12753660"/> || align="left"|Algeria1||0.5 |- | <ref name = "pmid12753660"/> || align="left"|Cameroon||0.4 |}

'''DQA1*0601:DQB1*0301''' (DQ7.6) is a globally rare haplotype, however it is found at high frequencies in the South Pacific and along the West Pacific rim. DQB1*0301 appears to be uniquely linked to DQA1*0601. DQ7.6 is positively associated with asthma,<ref name="pmid11802952">{{cite journal |vauthors=Guo X, Ni P, Li L | title = [Association between asthma and the polymorphism of HLA-DQ genes] | language = zh | journal = Zhonghua Jie He He Hu Xi Za Zhi | volume = 24 | issue = 3 | pages = 139–41 | year = 2001 | pmid = 11802952 }}</ref> pauciarticular juvenile arthritis without anti-nuclear antibodies,<ref name="pmid7788177">{{cite journal |vauthors=Donn RP, Thomson W, Pepper L, etal | title = Antinuclear antibodies in early onset pauciarticular juvenile chronic arthritis (JCA) are associated with HLA-DQB1*0603: a possible JCA-associated human leucocyte antigen haplotype | journal = Br. J. Rheumatol. | volume = 34 | issue = 5 | pages = 461–5 | year = 1995 | pmid = 7788177 | doi =10.1093/rheumatology/34.5.461 }}</ref> DQ7.6 is '''negatively associated''' (Protective against) juvenile diabetes,<ref name="pmid7624445">{{cite journal |vauthors=Chuang LM, Jou TS, Wu HP, etal | title = HLA DQA1 genotypes and its interaction with HLA DQB1 in Chinese IDDM living in Taiwan | journal = Proc. Natl. Sci. Counc. Repub. China B | volume = 19 | issue = 2 | pages = 73–9 | year = 1995 | pmid = 7624445 }}</ref> liver and spleen disease in ''Schistosoma japonicum'' infection,<ref name="pmid9602373">{{cite journal |vauthors=Waine GJ, Ross AG, Williams GM, Sleigh AC, McManus DP | title = HLA class II antigens are associated with resistance or susceptibility to hepatosplenic disease in a Chinese population infected with Schistosoma japonicum | journal = Int. J. Parasitol. | volume = 28 | issue = 4 | pages = 537–42 | year = 1998 | pmid = 9602373 | doi =10.1016/S0020-7519(98)00020-4 }}</ref> pulmonary tuberculosis.<ref name="pmid12358854">{{cite journal |vauthors=Vejbaesya S, Chierakul N, Luangtrakool K, Srinak D, Stephens HA | title = Associations of HLA class II alleles with pulmonary tuberculosis in Thais | journal = Eur. J. Immunogenet. | volume = 29 | issue = 5 | pages = 431–4 | year = 2002 | pmid = 12358854 | doi =10.1046/j.1365-2370.2002.00352.x }}</ref>

==References== {{reflist}} {{DQ serotypes}} {{Use dmy dates|date=January 2020}}

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