Major histocompatibility complex, class II, DQ beta 1, also known as HLA-DQB1, is a human gene and also denotes the genetic locus that contains this gene. The protein encoded by this gene is one of two proteins that are required to form the DQ heterodimer, a cell surface receptor essential to the function of the immune system.
Function
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).
Gene structure and polymorphisms
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.
Disease association
Autism
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.
Diabetes
Several alleles of HLA-DQB1 are associated with an increased risk of developing type 1 diabetes. 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).
Celiac disease
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.
Multiple sclerosis
Certain HLA-DQB1 alleles are also linked to a modest increased risk of multiple sclerosis.
Narcolepsy
Other HLA-DQB1 alleles are associated with a predisposition to narcolepsy, specifically HLA-DQB1*0602, which is carried by over 90% of patients with narcolepsy-cataplexy.
Alleles
| Serotype | DQB1 allele |
|---|---|
| DQ2 | *0201 |
| *0202 | |
| *0203 | |
| DQ4 | *0401 |
| *0402 | |
| DQ5 | *0501 |
| *0502 | |
| *0503 | |
| *0504 | |
| DQ6 | *0601 |
| *0602 | |
| *0603 | |
| *0604 | |
| *0605 | |
| *0609 | |
| DQ7 | *0301 |
| *0304 | |
| DQ8 | *0302 |
| *0305 | |
| DQ9 | *0303 |
See also
References
- ^ ENSG00000206237, ENSG00000231286, ENSG00000206302, ENSG00000179344, ENSG00000231939, ENSG00000225824 GRCh38: Ensembl release 89: ENSG00000233209, ENSG00000206237, ENSG00000231286, ENSG00000206302, ENSG00000179344, ENSG00000231939, ENSG00000225824 – Ensembl, May 2017
- ^ GRCm38: Ensembl release 89: ENSMUSG00000073421 – Ensembl, May 2017
- "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
- "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
- ^ "Entrez Gene: HLA-DQB1 major histocompatibility complex, class II, DQ beta 1".
- Lau M, Terasaki PI, Park MS (1994). "International Cell Exchange, 1994". Clinical Transplants: 467–88. PMID 7547576.
- Todd JA (April 1990). "Genetic control of autoimmunity in type 1 diabetes". Immunology Today. 11 (4): 122–9. doi:10.1016/0167-5699(90)90049-F. PMID 2187469.
- Todd JA (March 1997). "Genetics of type 1 diabetes". Pathologie-Biologie. 45 (3): 219–27. PMID 9296067.
- Redondo MJ, Fain PR, Eisenbarth GS (2001). "Genetics of type 1A diabetes". Recent Progress in Hormone Research. 56: 69–89. doi:10.1210/rp.56.1.69. PMID 11237226.
- Murray JA, Moore SB, Van Dyke CT, Lahr BD, Dierkhising RA, Zinsmeister AR, Melton LJ, Kroning CM, El-Yousseff M, Czaja AJ (December 2007). "HLA DQ gene dosage and risk and severity of celiac disease". Clinical Gastroenterology and Hepatology. 5 (12): 1406–12. doi:10.1016/j.cgh.2007.08.013. PMC 2175211. PMID 17919990.
- Dyment DA, Sadovnick AD, Ebers GC, Sadnovich AD (1997). "Genetics of multiple sclerosis". Human Molecular Genetics. 6 (10): 1693–8. doi:10.1093/hmg/6.10.1693. PMID 9300661.
- Schmidt H, Williamson D, Ashley-Koch A (May 2007). "HLA-DR15 haplotype and multiple sclerosis: a HuGE review". American Journal of Epidemiology. 165 (10): 1097–109. doi:10.1093/aje/kwk118. PMID 17329717.
- Kadotani H, Faraco J, Mignot E (May 1998). "Genetic studies in the sleep disorder narcolepsy". Genome Research. 8 (5): 427–34. doi:10.1101/gr.8.5.427. PMID 9582188.
- "Narcolepsy Research - FAQs".
External links
- Overview of all the structural information available in the PDB for UniProt: P01920 (HLA class II histocompatibility antigen, DQ beta 1 chain) at the PDBe-KB.
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