HLA-B27
| ||
| B*2705-β2MG with bound peptide 2bst | ||
major histocompatibility complex (human), class I, B27
| ||
| Alleles | B*2701, 2702, 2703, . . . | |
| Structure (See HLA-B) | Available 3D structures | |
| EBI-HLA | B*2701 | |
| B*2702 | ||
| B*2703 | ||
| B*2704 | ||
| B*2705 | 2bsr, 2bss, 2bst, 2a83, 1w0v, 1uxs, 1ogt, 1hsa, 1jgd, 1jge | |
| B*2706 | ||
| B*2709 | 1w0w, 1uxw, 1of2, 1k5n | |
Human Leukocyte Antigen (HLA) B27 (subtypes B*2701-2759) [1] is a class I surface antigen encoded by the B locus in the major histocompatibility complex (MHC) on chromosome 6 and presents antigenic peptides (derived from self and non-self antigens) to T-cells. HLA-B27 is strongly associated with ankylosing spondylitis (AS), and other associated inflammatory diseases referred to collectively as "spondyloarthritis". The prevalence of HLA-B27 varies markedly in the general population. For example, about 8% Caucasian, 4% North Africans, 2-9% Chinese, and 0.1-0.5% Japanese possess this gene.[2] In Northern Scandinavia (Lapland), 24% of people are HLA-B27 positive, while 1.8% have associated ankylosing spondylitis (AS).
Serotype
Note: Serotyping is currently obsolete, as gene sequencing and protein structure determinations are currently used to detect various alleles and subtypes of HLA-B27. Deletion of this chart is suggested. Additionally, the new allele frequency database is obsolete as well.
| B*27 | B27 | Sample | |
| allele | % | % | size (N) |
| 2701 | 100 | 9 | |
| 2702 | 67 | 417 | |
| 2703 | 88 | 26 | |
| 2704 | 97 | 34 | |
| 2705 | 97 | 1197 | |
| 2706 | 97 | 29 |
| freq | ||
| ref. | Population | (%) |
| [4] | Bulgaria | 4.6 |
| Bulgaria Gipsy | 4.5 | |
| Brazil Belo Horizonte | 2.6 | |
| Romanian | 2.2 | |
| Czech Republic | 1.9 | |
| Croatia | 1.7 | |
| Finland | 1.7 | |
| Spain E. Andalusia Gipsy | 1.5 | |
| Tunisia Tunis | 1.1 | |
| [4] | HLA B*2703 frequencies | |
| Romanian | 3.2 | |
| Kenya Nandi | 2.5 | |
| CAR Mbenzele Pygmy | 2.0 | |
| Sudanese | 1.8 | |
| Alaska Yupik Natives | 1.8 | |
| Senegal Niokholo Mandenka | 1.6 | |
| Guinea Bissau | 1.5 | |
| Kenya | 1.4 | |
| Georgia Svaneti Svans | 1.3 | |
| India North Delhi | 1.1 | |
| Ivory Coast Akan Adiopodoume | 1.1 | |
| [4] | HLA B*2704 frequencies | |
| PNG Karimui Plateau | 22.5 | |
| Taiwan Pazeh | 10.9 | |
| PNG West Schrader Ranges | 9.1 | |
| Tibet (China) Tibetans | 7.0 | |
| Taiwan Siraya | 6.9 | |
| Bulgaria Gipsy | 4.5 | |
| New Caledonia | 3.9 | |
| China Guangzhou | 2.5 | |
| India Mumbai Marathas | 2.5 | |
| Singapore Thai | 2.5 | |
| Thailand | 2.0 | |
| China Inner Mongolia | 1.5 | |
| China South Han | 1.2 | |
| Philippines Ivatan | 1.0 | |
| Taiwan Ami | 1.0 |
Disease associations
Spondylarthropathies
The relationship between HLA-B27 and many diseases has not yet been fully elucidated. Though it is associated with a wide range of pathology, it does not appear to be the sole mediator in development of disease. For example, while 90% of people with ankylosing spondylitis (AS) are HLA-B27 positive, only a fraction of people with HLA-B27 ever develop AS. This raises two important questions: why don't all HLA-B27 positive people develop AS, and why do some people who are HLA-B27 negative develop it? There are additional genes being discovered that also predispose to AS and associated diseases.[5] Additionally there are potential environmental factors (triggers) that may also play a role in susceptible individuals.,[6][7]
| USA Alaska Yupik | 11.5 | |
| Native American | 8.6 | |
| Arizona Pima ind. | 7.9 | |
| Belgium | 7.1 | |
| Mexico Tarahumara | 6.8 | |
| Finland | 6.1 | |
| Ireland South | 4.2 | |
| India Tamil Nadu Nadar | 4.1 | |
| India North Hindus | 3.8 | |
| Croatia | 3.7 | |
| Portugal North | 3.3 | |
| Mexico Guadalajara Mestizos | 2.9 | |
| Czech Republic | 2.8 | |
| Azores Terceira Island | 2.7 | |
| Azores Santa Maria & Sao Miguel | 2.6 | |
| South Korea pop 3 | 2.5 | |
| Cape Verde Northwestern Islands | 2.4 | |
| France South East | 2.3 | |
| Morocco Nador Metalsa Class I | 2.1 | |
| Portugal South | 2.0 | |
| Spain Eastern Andalusia Gipsy | 2.0 | |
| Italy North Pavia | 1.9 | |
| Azores Central Islands | 1.8 | |
| Bulgaria | 1.8 | |
| Israel Jews | 1.8 | |
| Georgia Tibilisi Kurds | 1.7 | |
| Brazil Belo Horizonte | 1.6 | |
| Cape Verde Southeastern Islands | 1.6 | |
| India New Delhi | 1.5 | |
| Mexico Sonora Seri | 1.5 |
Note: These are gene frequencies which are roughly half of the phenotype frequencies.
Associated pathology
In addition to its association with ankylosing spondylitis, HLA-B27 is implicated in reactive arthritis (Reiter's Syndrome), certain eye disorders such as acute anterior uveitis and iritis, psoriatic arthritis and ulcerative colitis associated spondyloarthritis. Behcet's disease and some forms of juvenile chronic arthritis as well. The shared association with HLA-B27 leads to increased clustering of these diseases.[8]
See also
External links
- HLA-B27 Syndromes at eMedicine by A. Luisa Di Lorenzo, MBBCh
- Bowness P (2002). "HLA B27 in health and disease: a double-edged sword?". Rheumatology (Oxford). 41 (8): 857–68. doi:10.1093/rheumatology/41.8.857. PMID 12154202.
- Online Mendelian Inheritance in Man (OMIM): 142830
- HLA-B27 at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
- BASDAI and Ankylosing Spondylitis
References
 | Constructs such as ibid., loc. cit. and idem are discouraged by Wikipedia's style guide for footnotes, as they are easily broken. Please improve this article by replacing them with named references (quick guide), or an abbreviated title. (October 2010) |
- ^ The HLA Complex in Biology and Medicine | editor: Mehra, NK | "HLA and Spondyloarthropathies" | chapter author: Khan, M.A. | chapter 16 | pages 259-275 | year published: 2010 | Publisher: Jayppee Brothers Medical Publishers, New Delhi, India | ISBN 978-81-8448-870-8
- ^ IBID, reference 1
- ^ derived from IMGT/HLA
- ^ a b c d Middleton D, Menchaca L, Rood H, Komerofsky R (2003). "New allele frequency database: http://www.allelefrequencies.net". Tissue Antigens. 61 (5): 403–7. doi:10.1034/j.1399-0039.2003.00062.x. PMID 12753660.
{{cite journal}}: External link in|title= - ^ Thomas GP, Brown MA. Genetics and Genomics of Ankylosing Spondylitis. Immunol Rev. 2010; 233:162-180.
- ^ IBID The HLA Complex in Biology and Medicine, Mehra, NK ed
- ^ IBID, Khan MA. Ankylosing Spondylitis
- ^ Kataria, RK (2004). "Spondyloarthropathies". American Family Physician. 69 (12): 2853–2860. PMID 15222650.
{{cite journal}}: Unknown parameter|coauthors=ignored (|author=suggested) (help); Unknown parameter|month=ignored (help)