title: Subtypes of HLA-B27: history and implications in the pathogenesis of ankylosing spondylitis.
abstract: HLA-B27 represents a family of 38 closely related cell surface proteins (encoded by the alleles HLA-B*2701-39) called subtypes of HLA-B27, most of which have evolved from the ubiquitous HLA-B*2705 (specifically the B*27052 allele). HLA-B27 subtypes are largely characterized by nucleotide substitutions (mostly nonsynonymous) in exons 2 and 3 which encode alpha1 and alpha2 domains ofthe peptide binding groove respectively. Table 1 shows the description of sequences of HLA-B27 allele sequences. The subtypes could have arisen from B*2705 by point mutation (B*2703, B*2709, B*2704), gene conversion (B*2701, B*2702, B*2708) and reciprocal recombination (B*2707) B*2706 could have arisen by interlocus gene conversion. Studies from different parts of the world reveal differences in the population distribution.
authors.affiliation: Division of Rheumatology and Clinical Immunogenetics, University of Texas Health Science Center, Houston, TX 77026, USA. john.d.reveille@uth.tmc.edu
authors.forename: John D
authors.initials: JD
authors.lastname: Reveille
authors.forename: Rashmi M
authors.initials: RM
authors.lastname: Maganti
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D019143:Evolution, Molecular; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D015796:HLA-B27 Antigen / Q000235:genetics / Q000276:immunology; D006801:Humans; D008024:Ligands; D026901:Membrane Transport Proteins / Q000378:metabolism; D018716:Molecular Mimicry; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic; D020033:Protein Isoforms / Q000235:genetics / Q000276:immunology; D016415:Sequence Alignment; D013167:Spondylitis, Ankylosing / Q000235:genetics / Q000276:immunology
chemical_list: D015796:HLA-B27 Antigen; D008024:Ligands; D026901:Membrane Transport Proteins; D020033:Protein Isoforms; C107762:tapasin