title: Human leukocyte antigen alleles and susceptibility to psoriatic arthritis.
abstract: OBJECTIVE
  Our purpose was to determine associations between HLA alleles and psoriatic arthritis (PsA).
  
  
  METHODS
  678 PsA cases and 688 healthy controls were analyzed in a case-control design. The difference in the proportion of cases and controls with at least 1 copy of HLA alleles were tested for significance using χ(2) test and Fisher's exact test. Association analyses of haplotypes inferred by the Expectation-Maximization algorithm were performed. In the family-based association study, data from 283 families were analyzed.
  
  
  RESULTS
  Univariate analysis revealed that cases were more likely to be carriers of HLA-C*01, -C*02, -C*06, -C*12, -B*27, -B*38 and -B*57, whereas controls were more likely to be carriers of HLA-C*03, -C*07, -B*07, -B*51, -DRB1*15 and -DQB1*0602. In haplotype analyses, PsA cases were more likely to be carriers of the HLA haplotypes -C*01/-B*27, -C*02/-B*27, -C*12/-B*38, and -C*06/-B*57, while controls were more likely to be carriers of the haplotypes -C*07/-B*07 and -C*15/-B*51. In the family-based association analysis, the HLA alleles -A*02, -B*27 and -DRB1*07 were preferentially transmitted to cases, whereas the alleles -A*03, -A*28, -B*51, -DRB1*11 and -DQB1*0301 were under transmitted.
  
  
  CONCLUSIONS
  This large case-control and family based association study shows that HLA-C*12/B*38, HLA-B*27 and HLA-C*06/B*57 are haplotypes (alleles) robustly associated with PsA. However, since patients with PsA also have psoriasis it is difficult to determine whether the primary association is with arthritis or psoriasis.
authors.affiliation: Psoriatic Arthritis Program, Centre for Prognosis Studies in The Rheumatic Diseases, Toronto Western Hospital, Toronto, Ontario, Canada.
authors.forename: Vinod
authors.initials: V
authors.lastname: Chandran
authors.forename: Shelley B
authors.initials: SB
authors.lastname: Bull
authors.forename: Fawnda J
authors.initials: FJ
authors.lastname: Pellett
authors.forename: Renise
authors.initials: R
authors.lastname: Ayearst
authors.forename: Proton
authors.initials: P
authors.lastname: Rahman
authors.forename: Dafna D
authors.initials: DD
authors.lastname: Gladman
mesh_terms: D000328:Adult; D000483:Alleles; D015535:Arthritis, Psoriatic / Q000235:genetics*; D016022:Case-Control Studies; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D006680:HLA Antigens / Q000235:genetics*; D006239:Haplotypes; D006650:Histocompatibility Testing; D006801:Humans; D015810:Linkage Disequilibrium; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D055815:Young Adult
chemical_list: D006680:HLA Antigens
keywords: AS; CASP; CASPAR; CD; Collaborative Association Study of Psoriasis; DNA; EM; Expectation–Maximization; FBAT; FDR; GWAS; HLA; JIA; KIR; LD; MHC; NK; OR; PCA; PCR; PsA; SNP; SSO; SSP; SpA; WHO; World Health Organization; ankylosing spondylitis; classification criteria for psoriatic arthritis; cluster of differentiation; deoxyribonucleic acid; false discovery rate; family-based association test; genome-wide association study; human leukocyte antigen; juvenile idiopathic arthritis; killer-cell immunoglobulin-like receptors; linkage disequilibrium; major histocompatibility complex; natural killer; odds ratio; polymerase chain reaction; principal component analysis; psoriatic arthritis; sequence specific oligonucleotide; sequence specific primers; single nucleotide polymorphisms; spondyloarthritis