title: HLA Class I and II profiles in São Miguel Island (Azores): genetic diversity and linkage disequilibrium.
abstract: BACKGROUND
  Human leukocyte antigen (HLA) genes are characterized by high levels of polymorphism and linkage disequilibrium (LD), important characteristics to study the genetic background of human populations and their genetic structure. Here, we analyse the allele distribution and LD extent of HLA class I and II in São Miguel Island population (Azores archipelago, Portugal).
  
  
  RESULTS
  The sample set was composed of 106 healthy blood donors living in São Miguel Island obtained from the anonymized Azorean DNA bank. HLA class I (-A, -B and -Cw) and class II (-DRB1, -DQB1, -DPA1 and -DPB1) genotyping was performed by PCR-SSP Olerup SSP (GenoVision Inc.), according to the manufacturer's instructions.Genetic diversity values, based on the 7 loci, ranged from 0.821 both for HLA-DPA1 and -DQB1 to 0.934 for HLA-B, with a mean value of 0.846. Analysis of 5 HLA-A-Cw-B-DRB1-DQB1 haplotypes revealed that A*01-Cw*07-B*08-DRB1*03-DQB1*02 is the most frequent in São Miguel (7.9%) followed by A*24-B*08-Cw*07-DRB1*03-DQB1*02 (3.8%). In addition, even though the reports of high LD for HLA markers in worldwide populations, São Miguel islanders do not have extensive LD (average D' = 0.285).
  
  
  CONCLUSIONS
  In summary, the results demonstrate high variability of HLA in São Miguel Island population as well as absence of genetic structure and extensive LD. The data here presented suggest that in São Miguel islanders autoimmune diseases studies will necessarily encompass a more focused analysis of HLA extended haplotypes as well as the evaluation of other non-HLA candidate genes.
authors.affiliation: Molecular Genetics and Pathology Unit, Hospital of Divino Espírito Santo of Ponta Delgada, EPE, São Miguel Island, Azores, Portugal. lmotavieira@hdes.pt.
authors.forename: Paula R
authors.initials: PR
authors.lastname: Pacheco
authors.forename: Claudia C
authors.initials: CC
authors.lastname: Branco
authors.forename: Cidália T
authors.initials: CT
authors.lastname: Gomes
authors.forename: Rita
authors.initials: R
authors.lastname: Cabral
authors.forename: Luisa
authors.initials: L
authors.lastname: Mota-Vieira
references.citation: Tissue Antigens. 2005 Sep;66(3):217-30
references.pmid: 16101833
references.citation: Genet Mol Biol. 2009 Apr;32(2):220-6
references.pmid: 21637671
references.citation: Ann Hum Genet. 2005 Mar;69(Pt 2):145-56
references.pmid: 15720296
references.citation: Ann Hum Biol. 2008 Jan-Feb;35(1):65-74
references.pmid: 18274926
references.citation: Proc Biol Sci. 2009 Feb 22;276(1657):657-65
references.pmid: 18986972
references.citation: Tissue Antigens. 2001 Mar;57(3):200-7
references.pmid: 11285127
references.citation: Tissue Antigens. 2001 Feb;57(2):128-37
references.pmid: 11260507
references.citation: Am J Hum Biol. 2008 May-Jun;20(3):364-6
references.pmid: 18257075
references.citation: Ann Hum Genet. 2003 Sep;67(Pt 5):433-56
references.pmid: 12940917
references.citation: Hum Immunol. 2001 Sep;62(9):889-900
references.pmid: 11543891
references.citation: Nat Genet. 2006 May;38(5):556-60
references.pmid: 16582909
references.citation: Nat Genet. 2006 Oct;38(10):1166-72
references.pmid: 16998491
references.citation: Am J Hum Genet. 2001 Jan;68(1):191-197
references.pmid: 11083947
references.citation: Tissue Antigens. 2005 Jul;66(1):26-36
references.pmid: 15982254
references.citation: Ann Hum Genet. 2005 Mar;69(Pt 2):135-44
references.pmid: 15720295
references.citation: Tissue Antigens. 2000 Mar;55(3):239-49
references.pmid: 10777099
references.citation: Genetics. 2006 Aug;173(4):2121-42
references.pmid: 16702436
references.citation: Tissue Antigens. 2002 Aug;60(2):111-21
references.pmid: 12392505
references.citation: Tissue Antigens. 2007 Apr;69 Suppl 1:198-202
references.pmid: 17445200
references.citation: Am J Hum Biol. 2006 Mar-Apr;18(2):223-6
references.pmid: 16493635
references.citation: Hum Immunol. 2001 Sep;62(9):910-21
references.pmid: 11543893
references.citation: Comput Appl Biosci. 1996 Aug;12(4):357-8
references.pmid: 8902363
references.citation: Am J Hum Biol. 2008 Jan-Feb;20(1):118-20
references.pmid: 17990326