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Genetics Home Reference: your guide to understanding genetic conditions
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HLA-DRB1

Reviewed June 2014

What is the official name of the HLA-DRB1 gene?

The official name of this gene is “major histocompatibility complex, class II, DR beta 1.”

HLA-DRB1 is the gene's official symbol. The HLA-DRB1 gene is also known by other names, listed below.

What is the normal function of the HLA-DRB1 gene?

The HLA-DRB1 gene provides instructions for making a protein that plays a critical role in the immune system. The HLA-DRB1 gene is part of a family of genes called the human leukocyte antigen (HLA) complex. The HLA complex helps the immune system distinguish the body's own proteins from proteins made by foreign invaders such as viruses and bacteria.

The HLA complex is the human version of the major histocompatibility complex (MHC), a gene family that occurs in many species. The HLA-DRB1 gene belongs to a group of MHC genes called MHC class II. MHC class II genes provide instructions for making proteins that are present on the surface of certain immune system cells. These proteins attach to protein fragments (peptides) outside the cell. MHC class II proteins display these peptides to the immune system. If the immune system recognizes the peptides as foreign (such as viral or bacterial peptides), it triggers a response to attack the invading viruses or bacteria.

The protein produced from the HLA-DRB1 gene, called the beta chain, attaches (binds) to another protein called the alpha chain, which is produced from the HLA-DRA gene. Together, they form a functional protein complex called the HLA-DR antigen-binding heterodimer. This complex displays foreign peptides to the immune system to trigger the body's immune response.

Each MHC class II gene has many possible variations, allowing the immune system to react to a wide range of foreign invaders. Researchers have identified hundreds of different versions (alleles) of the HLA-DRB1 gene, each of which is given a particular number (such as HLA-DRB1*04:01).

Does the HLA-DRB1 gene share characteristics with other genes?

The HLA-DRB1 gene belongs to a family of genes called HLA (histocompatibility complex genes). It also belongs to a family of genes called immunoglobulin superfamily, C1-set domain containing (immunoglobulin superfamily, C1-set domain containing).

A gene family is a group of genes that share important characteristics. Classifying individual genes into families helps researchers describe how genes are related to each other. For more information, see What are gene families? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genefamilies) in the Handbook.

How are changes in the HLA-DRB1 gene related to health conditions?

autoimmune Addison disease - associated with the HLA-DRB1 gene

Certain variations in the HLA-DRB1 gene have been linked to an increased risk of developing an autoimmune disorder called autoimmune Addison disease. Autoimmune disorders occur when the immune system malfunctions and attacks the body's tissues and organs. In autoimmune Addison disease, the immune system attacks the adrenal glands, which are small hormone-producing glands located on top of each kidney. Loss of hormones produced by the adrenal glands leads to the features of the condition, which include extreme tiredness (fatigue), nausea, low blood pressure (hypotension), and abnormally dark areas of skin (hyperpigmentation), especially in regions that experience a lot of friction such as the armpits, elbows, and knuckles. A particular HLA-DRB1 gene variant called HLA-DRB1*04:04 is the most well-known risk factor for autoimmune Addison disease.

Normally, the immune system responds only to proteins made by foreign invaders, not to the body's own proteins. In autoimmune Addison disease, however, an immune response is triggered by a normal adrenal gland protein; in about 85 percent of people with autoimmune Addison disease, the protein is 21-hydroxylase. 21-hydroxylase is found in the adrenal glands where it plays a key role in producing a variety of hormones that regulate many essential functions in the body. The prolonged immune attack triggered by 21-hydroxylase damages the adrenal glands (specifically the outer layers of the glands known, collectively, as the adrenal cortex), preventing hormone production. A shortage of adrenal hormones (adrenal insufficiency) disrupts several normal functions in the body, leading to the diverse features of autoimmune Addison disease. It is not clear how HLA-DRB1*04:04 and other HLA-DRB1 variations are involved in the inappropriate immune response that causes autoimmune Addison disease.

autoimmune disorders - associated with the HLA-DRB1 gene

Normal variations of the HLA-DRB1 gene have been associated with many other autoimmune disorders, including pemphigus, sarcoidosis, and others listed on this page. Pemphigus is a condition that causes severe blistering of the skin and mucous membranes (such as the moist lining of the mouth). Sarcoidosis is a disorder in which inflammation occurs in many organs and tissues of the body.

It is unclear how different versions of the HLA-DRB1 gene influence the risk of developing autoimmune disorders. These disorders typically result from a combination of multiple environmental and genetic factors. Changes in other HLA and non-HLA genes, some of which remain unknown, also likely contribute to the risk of developing these complex conditions.

multiple sclerosis - associated with the HLA-DRB1 gene

Variations in the HLA-DRB1 gene have been associated with an increased risk of developing multiple sclerosis. This condition affects the brain and spinal cord (central nervous system), causing muscle weakness, poor coordination, numbness, and a variety of other health problems. One variant of this gene, called HLA-DRB1*15:01, is the most strongly linked genetic factor for the risk of multiple sclerosis.

Because the HLA-DRB1 gene is involved in the immune system, changes in it might be related to the autoimmune response and inflammation that damage nerves and the protective coating surrounding them (the myelin sheath), leading to the signs and symptoms of multiple sclerosis. However, it is unclear exactly what role HLA-DRB1 gene variants play in development of multiple sclerosis. A combination of genetic and environmental factors is likely involved in this condition.

rheumatoid arthritis - associated with the HLA-DRB1 gene

Several common variations of the HLA-DRB1 gene are associated with a person's risk of developing rheumatoid arthritis. This disease causes chronic abnormal inflammation that primarily affects the joints. HLA-DRB1 is one of several genes in the HLA complex that have been associated with rheumatoid arthritis; variations of this gene are the most significant known genetic risk factor for the disease.

The HLA-DRB1 gene variations associated with an increased risk of rheumatoid arthritis affect single protein building blocks (amino acids) in the beta chain. These changes occur near the antigen-recognizing binding groove, which is the part of the protein that attaches (binds) to viral or bacterial peptides. This binding triggers the immune response that attacks foreign invaders. Although the mechanism by which HLA-DRB1 gene variations increase the risk of rheumatoid arthritis is unclear, researchers suspect it is related to changes in peptide binding that stimulate an abnormal immune response. However, many other genetic and environmental factors also contribute to a person's overall risk of developing rheumatoid arthritis.

A few variations of the HLA-DRB1 gene appear to decrease the risk of developing rheumatoid arthritis. It is unclear why these particular changes may be protective.

type 1 diabetes - associated with the HLA-DRB1 gene

Combinations of variations in the HLA-DRB1 gene and other HLA genes affect the risk of type 1 diabetes. Type 1 diabetes is characterized by high blood sugar levels resulting from a shortage of the hormone insulin and is caused by autoimmune damage to insulin-producing cells in the pancreas.

Type 1 diabetes risk is most increased by two specific combinations of variations of the HLA-DRB1 gene and other HLA genes called HLA-DQA1 and HLA-DQB1. Combinations of HLA gene variants are called HLA haplotypes. One haplotype, written as DRB1*03:01-DQA1*05:01-DQB1*02, is called DR3. The other haplotype, written as DRB1*04:01/02/04/05/08-DQA1*03:01-DQB1*02, is called DR4. People at highest risk of developing type 1 diabetes have one copy of the DR3 haplotype and one copy of the DR4 haplotype in each cell. Other HLA haplotypes only mildly increase the risk of type 1 diabetes, while some haplotypes seem to protect against developing this condition. Variations in other genes and environmental factors are also thought to affect the risk of this complex disorder.

Where is the HLA-DRB1 gene located?

Cytogenetic Location: 6p21.3

Molecular Location on chromosome 6: base pairs 32,578,768 to 32,589,835

The HLA-DRB1 gene is located on the short (p) arm of chromosome 6 at position 21.3.

The HLA-DRB1 gene is located on the short (p) arm of chromosome 6 at position 21.3.

More precisely, the HLA-DRB1 gene is located from base pair 32,578,768 to base pair 32,589,835 on chromosome 6.

See How do geneticists indicate the location of a gene? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genelocation) in the Handbook.

Where can I find additional information about HLA-DRB1?

You and your healthcare professional may find the following resources about HLA-DRB1 helpful.

You may also be interested in these resources, which are designed for genetics professionals and researchers.

What other names do people use for the HLA-DRB1 gene or gene products?

  • DRB1
  • DRw10
  • DW2.2/DR2.2
  • HLA class II histocompatibility antigen, DR-1 beta chain
  • HLA-DR1B
  • HLA-DRB
  • 2B1F_HUMAN
  • 2B1G_HUMAN
  • 2B13_HUMAN
  • human leucocyte antigen DRB1
  • lymphocyte antigen DRB1
  • major histocompatibility complex, class II, DR beta 1 precursor
  • MHC class II antigen
  • MHC class II HLA-DR beta 1 chain
  • MHC class II HLA-DR-beta cell surface glycoprotein
  • MHC class II HLA-DRw10-beta
  • SS1

See How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.

What glossary definitions help with understanding HLA-DRB1?

acids ; adrenal cortex ; adrenal glands ; arthritis ; autoimmune ; bacteria ; cell ; central nervous system ; chronic ; class ; diabetes ; gene ; haplotype ; high blood sugar ; HLA ; hormone ; hypotension ; idiopathic ; immune response ; immune system ; inflammation ; insulin ; juvenile ; kidney ; leukocyte ; lymphocyte ; MHC ; mucous ; myelin sheath ; nervous system ; pancreas ; peptide ; protein ; sarcoidosis ; sclerosis

You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://www.ghr.nlm.nih.gov/glossary).

References

  • Alcina A, Abad-Grau Mdel M, Fedetz M, Izquierdo G, Lucas M, Fernández O, Ndagire D, Catalá-Rabasa A, Ruiz A, Gayán J, Delgado C, Arnal C, Matesanz F. Multiple sclerosis risk variant HLA-DRB1*1501 associates with high expression of DRB1 gene in different human populations. PLoS One. 2012;7(1):e29819. doi: 10.1371/journal.pone.0029819. Epub 2012 Jan 13. (http://www.ncbi.nlm.nih.gov/pubmed/22253788?dopt=Abstract)
  • Aly TA, Ide A, Jahromi MM, Barker JM, Fernando MS, Babu SR, Yu L, Miao D, Erlich HA, Fain PR, Barriga KJ, Norris JM, Rewers MJ, Eisenbarth GS. Extreme genetic risk for type 1A diabetes. Proc Natl Acad Sci U S A. 2006 Sep 19;103(38):14074-9. Epub 2006 Sep 11. (http://www.ncbi.nlm.nih.gov/pubmed/16966600?dopt=Abstract)
  • Chinoy H, Lamb JA, Ollier WE, Cooper RG. An update on the immunogenetics of idiopathic inflammatory myopathies: major histocompatibility complex and beyond. Curr Opin Rheumatol. 2009 Nov;21(6):588-93. doi: 10.1097/BOR.0b013e3283315a22. Review. (http://www.ncbi.nlm.nih.gov/pubmed/19730377?dopt=Abstract)
  • Gombos Z, Hermann R, Kiviniemi M, Nejentsev S, Reimand K, Fadeyev V, Peterson P, Uibo R, Ilonen J. Analysis of extended human leukocyte antigen haplotype association with Addison's disease in three populations. Eur J Endocrinol. 2007 Dec;157(6):757-61. (http://www.ncbi.nlm.nih.gov/pubmed/18057383?dopt=Abstract)
  • OMIM: MAJOR HISTOCOMPATIBILITY COMPLEX, CLASS II, DR BETA-1 (http://omim.org/entry/142857)
  • Hor H, Kutalik Z, Dauvilliers Y, Valsesia A, Lammers GJ, Donjacour CE, Iranzo A, Santamaria J, Peraita Adrados R, Vicario JL, Overeem S, Arnulf I, Theodorou I, Jennum P, Knudsen S, Bassetti C, Mathis J, Lecendreux M, Mayer G, Geisler P, Benetó A, Petit B, Pfister C, Bürki JV, Didelot G, Billiard M, Ercilla G, Verduijn W, Claas FH, Vollenweider P, Waeber G, Waterworth DM, Mooser V, Heinzer R, Beckmann JS, Bergmann S, Tafti M. Genome-wide association study identifies new HLA class II haplotypes strongly protective against narcolepsy. Nat Genet. 2010 Sep;42(9):786-9. doi: 10.1038/ng.647. Epub 2010 Aug 15. Erratum in: Nat Genet. 2011 Apr;43(4):388. Vollenwider, Peter [corrected to Vollenweider, Peter]. (http://www.ncbi.nlm.nih.gov/pubmed/20711174?dopt=Abstract)
  • NCBI Gene (http://www.ncbi.nlm.nih.gov/gene/3123)
  • Noble JA, Valdes AM. Genetics of the HLA region in the prediction of type 1 diabetes. Curr Diab Rep. 2011 Dec;11(6):533-42. doi: 10.1007/s11892-011-0223-x. Review. (http://www.ncbi.nlm.nih.gov/pubmed/21912932?dopt=Abstract)
  • Prahalad S, Glass DN. A comprehensive review of the genetics of juvenile idiopathic arthritis. Pediatr Rheumatol Online J. 2008 Jul 21;6:11. doi: 10.1186/1546-0096-6-11. (http://www.ncbi.nlm.nih.gov/pubmed/18644131?dopt=Abstract)
  • Raychaudhuri S, Sandor C, Stahl EA, Freudenberg J, Lee HS, Jia X, Alfredsson L, Padyukov L, Klareskog L, Worthington J, Siminovitch KA, Bae SC, Plenge RM, Gregersen PK, de Bakker PI. Five amino acids in three HLA proteins explain most of the association between MHC and seropositive rheumatoid arthritis. Nat Genet. 2012 Jan 29;44(3):291-6. doi: 10.1038/ng.1076. (http://www.ncbi.nlm.nih.gov/pubmed/22286218?dopt=Abstract)
  • Rottembourg D, Deal C, Lambert M, Mallone R, Carel JC, Lacroix A, Caillat-Zucman S, le Deist F. 21-Hydroxylase epitopes are targeted by CD8 T cells in autoimmune Addison's disease. J Autoimmun. 2010 Dec;35(4):309-15. doi: 10.1016/j.jaut.2010.07.001. Epub 2010 Aug 3. (http://www.ncbi.nlm.nih.gov/pubmed/20685079?dopt=Abstract)
  • Skinningsrud B, Lie BA, Lavant E, Carlson JA, Erlich H, Akselsen HE, Gervin K, Wolff AB, Erichsen MM, Løvås K, Husebye ES, Undlien DE. Multiple loci in the HLA complex are associated with Addison's disease. J Clin Endocrinol Metab. 2011 Oct;96(10):E1703-8. doi: 10.1210/jc.2011-0645. Epub 2011 Aug 3. (http://www.ncbi.nlm.nih.gov/pubmed/21816777?dopt=Abstract)
  • Steck AK, Rewers MJ. Genetics of type 1 diabetes. Clin Chem. 2011 Feb;57(2):176-85. doi: 10.1373/clinchem.2010.148221. Epub 2011 Jan 4. Review. (http://www.ncbi.nlm.nih.gov/pubmed/21205883?dopt=Abstract)
  • Viatte S, Plant D, Raychaudhuri S. Genetics and epigenetics of rheumatoid arthritis. Nat Rev Rheumatol. 2013 Mar;9(3):141-53. doi: 10.1038/nrrheum.2012.237. Epub 2013 Feb 5. Review. (http://www.ncbi.nlm.nih.gov/pubmed/23381558?dopt=Abstract)
  • Yu L, Brewer KW, Gates S, Wu A, Wang T, Babu SR, Gottlieb PA, Freed BM, Noble J, Erlich HA, Rewers MJ, Eisenbarth GS. DRB1*04 and DQ alleles: expression of 21-hydroxylase autoantibodies and risk of progression to Addison's disease. J Clin Endocrinol Metab. 1999 Jan;84(1):328-35. (http://www.ncbi.nlm.nih.gov/pubmed/9920103?dopt=Abstract)

 

The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.

 
Reviewed: June 2014
Published: July 7, 2014