title: Haplotypes of the endothelial protein C receptor gene and Behçet's disease.
abstract: BACKGROUND
  Behçet's disease is a vasculitis of unknown cause in which thrombosis occurs in about 25% of patients. Two haplotypes of the endothelial protein C receptor gene, H1 and H3, are associated with the risk of thrombosis. Thus, the objective of this study was to evaluate the influence of these haplotypes on the thrombosis risk in Behçet's disease.
  
  
  METHODS
  We evaluated the H1 and H3 haplotypes in 87 patients with Behçet's disease, 19 with and 68 without a history of thrombosis, and in 260 healthy individuals. We also measured protein C, activated protein C, and soluble endothelial protein C receptor levels in all individuals.
  
  
  RESULTS
  The presence of the H1 haplotype seemed to protect Behçet's patients against thrombosis (odds ratio 0.21; 95% CI 0.1-0.8; p=0.023), whereas the frequency of the H3 haplotype was lower in patients than in control individuals (0.19; 0.1-0.5; p=0.006). Furthermore, the H1 haplotype was associated with increased levels of activated protein C, whereas the H3 haplotype was associated with the highest soluble endothelial protein C levels. Moreover, activated protein C levels were lower in patients with than in patients without posterior uveitis (p<0.001).
  
  
  CONCLUSIONS
  These findings indicate that the H1 haplotype protects Behçet's patients from thrombosis, likely via increased levels of activated protein C, whereas individuals carrying the H3 haplotype seem to be protected from the clinical manifestations associated with Behçet's disease, probably via increased soluble endothelial protein C levels.
authors.affiliation: Research Center, Hospital Universitario La Fe, Valencia, Spain.
authors.forename: Silvia
authors.initials: S
authors.lastname: Navarro
authors.forename: Elena
authors.initials: E
authors.lastname: Bonet
authors.forename: Pilar
authors.initials: P
authors.lastname: Medina
authors.forename: Laura
authors.initials: L
authors.lastname: Martos
authors.forename: José M
authors.initials: JM
authors.lastname: Ricart
authors.forename: Amparo
authors.initials: A
authors.lastname: Vayá
authors.forename: José
authors.initials: J
authors.lastname: Todolí
authors.forename: Jordi
authors.initials: J
authors.lastname: Fontcuberta
authors.forename: Amparo
authors.initials: A
authors.lastname: Estellés
authors.forename: Francisco
authors.initials: F
authors.lastname: España
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000235:genetics*; D001528:Behcet Syndrome / Q000453:epidemiology* / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D015897:Comorbidity; D000074283:Endothelial Protein C Receptor; D005260:Female; D020022:Genetic Predisposition to Disease / Q000453:epidemiology / Q000235:genetics*; D006239:Haplotypes / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011956:Receptors, Cell Surface / Q000235:genetics*; D012307:Risk Factors; D013030:Spain / Q000453:epidemiology; D013927:Thrombosis / Q000453:epidemiology* / Q000235:genetics*; D055815:Young Adult
chemical_list: D015703:Antigens, CD; D000074283:Endothelial Protein C Receptor; C478370:PROCR protein, human; D011956:Receptors, Cell Surface