title: Haplotypes of the EPCR gene, prothrombin levels, and the risk of venous thrombosis in carriers of the prothrombin G20210A mutation.
abstract: BACKGROUND
  Haplotypes A1 and A3 in the endothelial protein C receptor (EPCR) gene are tagged by 4678G/C and 4600A/G respectively. We assessed whether these haplotypes modify the risk of venous thromboembolism in carriers of the prothrombin 20210A allele.
  
  
  METHODS
  We genotyped 4678G/C and 4600A/G in 246 20210A carriers: 84 venous thromboembolism propositi and 162 relatives (13 symptomatic), and in 140 relatives not carrying the 20210A variant. Prothrombin and soluble EPCR (sEPCR) levels were also measured.
  
  
  RESULTS
  Among propositi, the mean age at first onset was lower in carriers (35 +/- 8 years) than non-carriers of the 4600G allele (44 +/- 14 years) (p = 0.004). The probability of being free of thrombosis at age 40 was lower in 20210A carriers with the EPCR 4600G allele (p = 0.015). The frequency of the 4600G allele (p=0.002) and the levels of prothrombin antigen (p = 0.002) and sEPCR (p < 0.001) were higher in the propositi than in their asymptomatic relatives. Multivariate analyses showed that the presence of the 4600G allele (OR = 2.5, 95% confidence interval 1.3-5.0), sEPCR > 147 ng/mL (2.8, 1.5-5.2) and prothrombin > 129% (3.8, 1.8-8.3) all increased the thrombotic risk. In bivariate analysis, including the 4600G allele and sEPCR > 147 ng/mL, only the latter remained associated with risk.
  
  
  CONCLUSIONS
  These results show that in 20210A carriers the venous thromboembolism risk is influenced both by the actual prothrombin levels and by the EPCR A3 haplotype, via its effect on sEPCR levels.
authors.affiliation: Research Center, La Fe University Hospital, Valencia, Spain.
authors.forename: Silvia
authors.initials: S
authors.lastname: Navarro
authors.forename: Pilar
authors.initials: P
authors.lastname: Medina
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Mira
authors.forename: Amparo
authors.initials: A
authors.lastname: Estellés
authors.forename: Piedad
authors.initials: P
authors.lastname: Villa
authors.forename: Fernando
authors.initials: F
authors.lastname: Ferrando
authors.forename: Amparo
authors.initials: A
authors.lastname: Vayá
authors.forename: Rogier M
authors.initials: RM
authors.lastname: Bertina
authors.forename: Francisco
authors.initials: F
authors.lastname: España
mesh_terms: D000328:Adult; D017668:Age of Onset; D000483:Alleles; D015703:Antigens, CD / Q000737:chemistry* / Q000235:genetics*; D000074283:Endothelial Protein C Receptor; D005260:Female; D006239:Haplotypes; D006579:Heterozygote; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D011486:Protein C / Q000378:metabolism; D011516:Prothrombin / Q000096:biosynthesis* / Q000235:genetics*; D011956:Receptors, Cell Surface / Q000737:chemistry* / Q000235:genetics*; D012306:Risk; D020246:Venous Thrombosis / Q000097:blood* / Q000175:diagnosis / Q000235:genetics*
chemical_list: D015703:Antigens, CD; D000074283:Endothelial Protein C Receptor; C478370:PROCR protein, human; D011486:Protein C; D011956:Receptors, Cell Surface; D011516:Prothrombin