HLA-DQB1#Celiac disease

HLA-DQB1 belongs to the HLA class II beta chain paralogues. This class II molecule is a heterodimer consisting of an alpha (DQA) and a beta chain (DQB), both anchored in the membrane. It plays a central role in the immune system by presenting peptides derived from extracellular proteins. Class II molecules are expressed in antigen-presenting cells (APC: B lymphocytes, dendritic cells, macrophages).

The beta chain is approximately 26-28 kDa and it contains 6 exons. Exon one encodes the leader peptide, exons 2 and 3 encode the two extracellular protein domains, exon 4 encodes the transmembrane domain, and exon 5 encodes the cytoplasmic tail. Within the DQ molecule, both the alpha chain and the beta chain contain the polymorphisms specifying the peptide binding specificities, resulting in up to 4 different molecules. Typing for these polymorphisms is routinely done for bone marrow transplantation.{{cite journal | vauthors = Lau M, Terasaki PI, Park MS | title = International Cell Exchange, 1994 | journal = Clinical Transplants | pages = 467–88 | year = 1994 | pmid = 7547576 }}

A four-loci genotype study showed that A*01-B*07-DRB1*0701-

DQB1*0602 (P = 0.001, OR 41.9) and

the A*31-B*51-DRB1*0103-

DQB1*0302 (P = 0.012, OR 4.8) are

positively associated with autism among Saudi patients.

Several alleles of HLA-DQB1 are associated with an increased risk of developing type 1 diabetes.{{cite journal | vauthors = Todd JA | title = Genetic control of autoimmunity in type 1 diabetes | journal = Immunology Today | volume = 11 | issue = 4 | pages = 122–9 | date = April 1990 | pmid = 2187469 | doi = 10.1016/0167-5699(90)90049-F }}{{cite journal | vauthors = Todd JA | title = Genetics of type 1 diabetes | journal = Pathologie-Biologie | volume = 45 | issue = 3 | pages = 219–27 | date = March 1997 | pmid = 9296067 }}{{cite journal | vauthors = Redondo MJ, Fain PR, Eisenbarth GS | title = Genetics of type 1A diabetes | journal = Recent Progress in Hormone Research | volume = 56 | pages = 69–89 | year = 2001 | pmid = 11237226 | doi = 10.1210/rp.56.1.69 | doi-access = free }} The locus also has the genetic name IDDM1 as it is the highest genetic risk for type 1 diabetes. Again the DQB1*0201 and DQB1*0302 alleles, particularly the phenotype DQB1*0201/*0302 has a high risk of late onset type 1 diabetes. The risk is partially shared with the HLA-DR locus (DR3 and DR4 serotypes).

Celiac1 is a genetic name for DQB1, the HLA DQB1*0201, *0202, and *0302 encode genes that mediate the autoimmune coeliac disease. Homozygotes of DQB1*0201 have a higher risk of developing the celiac disease, relative to any other genetic locus.{{cite journal | vauthors = Murray JA, Moore SB, Van Dyke CT, Lahr BD, Dierkhising RA, Zinsmeister AR, Melton LJ, Kroning CM, El-Yousseff M, Czaja AJ | title = HLA DQ gene dosage and risk and severity of celiac disease | journal = Clinical Gastroenterology and Hepatology | volume = 5 | issue = 12 | pages = 1406–12 | date = December 2007 | pmid = 17919990 | pmc = 2175211 | doi = 10.1016/j.cgh.2007.08.013 }}

Certain HLA-DQB1 alleles are also linked to a modest increased risk of multiple sclerosis.{{cite journal | vauthors = Dyment DA, Sadovnick AD, Ebers GC, Sadnovich AD | title = Genetics of multiple sclerosis | journal = Human Molecular Genetics | volume = 6 | issue = 10 | pages = 1693–8 | year = 1997 | pmid = 9300661 | doi = 10.1093/hmg/6.10.1693 | doi-access = free }}{{cite journal | vauthors = Schmidt H, Williamson D, Ashley-Koch A | title = HLA-DR15 haplotype and multiple sclerosis: a HuGE review | journal = American Journal of Epidemiology | volume = 165 | issue = 10 | pages = 1097–109 | date = May 2007 | pmid = 17329717 | doi = 10.1093/aje/kwk118 | doi-access = free }}

Other HLA-DQB1 alleles are associated with a predisposition to narcolepsy,{{cite journal | vauthors = Kadotani H, Faraco J, Mignot E | title = Genetic studies in the sleep disorder narcolepsy | journal = Genome Research | volume = 8 | issue = 5 | pages = 427–34 | date = May 1998 | pmid = 9582188 | doi = 10.1101/gr.8.5.427 | doi-access = free }} specifically HLA-DQB1*0602, which is carried by over 90% of patients with narcolepsy-cataplexy.{{cite web|title=Narcolepsy Research - FAQs|url=http://med.stanford.edu/narcolepsy/faq1.html}}

• Major histocompatibility complex
• Human leukocyte antigen
• HLA-DQ

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• {{PDBe-KB2|P01920|HLA class II histocompatibility antigen, DQ beta 1 chain}}

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{{Surface antigens}}

Category:MHC class II

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