title: AB0 blood group and risk of venous or arterial thrombosis in carriers of factor V Leiden or prothrombin G20210A polymorphisms.
abstract: BACKGROUND
  Routine analyses for thrombophilia include determination of the presence of factor V Leiden and prothrombin 20210A polymorphisms. However, the usefulness of these determinations is controversial and the clinical benefit remains questioned because of the moderate risk of associated thrombosis in carriers. In the search for clusters of thrombotic risk factors to estimate individual risk better, we studied the effect of AB0 blood group, a highly prevalent factor with mild prothrombotic features, on the risk and severity of venous and arterial thromboses in carriers of these polymorphisms.
  
  
  METHODS
  We genotyped the AB0 blood group in 981 carriers of factor V Leiden or prothrombin 20210A polymorphisms. In order to avoid the over-representation of a particular genotype and to suppress confounding factors, we included only non-related heterozygous carriers without additional genetic risk factors. We studied 609 patients with venous thromboembolism (287 with factor V Leiden, and 322 with prothrombin 20210A), 174 patients with myocardial infarction (78 with factor V Leiden, and 96 with prothrombin 20210A), and 198 controls (96 with factor V Leiden, and 102 with prothrombin 20210A).
  
  
  RESULTS
  Non-OO blood group did not increase the risk of myocardial infarction in carriers of factor V Leiden or prothrombin 20210A. However, non-OO blood group contributed significantly to the expression of venous thrombosis associated with both factor V Leiden (OR: 1.76; 95%CI: 1.06-2.91) and prothrombin 20210A (OR: 2.17; 95%CI: 1.33-3.53). Exclusion of A(2)A(2) and A(2)O from the non-00 blood group (because factor VIII-von Willebrand factor levels are similar in these and the 00 blood group) increased the thrombotic risk. Finally, non-OO blood group was associated with an earlier onset in symptomatic carriers of these polymorphisms.
  
  
  CONCLUSIONS
  Our study suggests that non-OO blood group increases the risk and severity of venous thrombosis in carriers of prothrombotic polymorphisms. Thus, AB0 phenotyping or genotyping analyses may be valuable components in assessing future thrombophilic risk profiles and might have implications for the policy of thrombosis prophylaxis and treatment.
authors.affiliation: Centro Regional de Hemodonación, C/ Ronda de Garay s/n, Murcia 30003 Spain.
authors.forename: Antonia
authors.initials: A
authors.lastname: Miñano
authors.forename: Adriana
authors.initials: A
authors.lastname: Ordóñez
authors.forename: Francisco
authors.initials: F
authors.lastname: España
authors.forename: José Ramón
authors.initials: JR
authors.lastname: González-Porras
authors.forename: Ramón
authors.initials: R
authors.lastname: Lecumberri
authors.forename: Jordi
authors.initials: J
authors.lastname: Fontcuberta
authors.forename: Pilar
authors.initials: P
authors.lastname: Llamas
authors.forename: Francisco
authors.initials: F
authors.lastname: Marín
authors.forename: Amparo
authors.initials: A
authors.lastname: Estellés
authors.forename: Ignacio
authors.initials: I
authors.lastname: Alberca
authors.forename: Vicente
authors.initials: V
authors.lastname: Vicente
authors.forename: Javier
authors.initials: J
authors.lastname: Corral
mesh_terms: D000017:ABO Blood-Group System; D000328:Adult; D005165:Factor V / Q000235:genetics*; D005260:Female; D005838:Genotype; D006579:Heterozygote; D006801:Humans; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D011516:Prothrombin / Q000235:genetics*; D012306:Risk; D019851:Thrombophilia / Q000235:genetics; D013927:Thrombosis / Q000235:genetics*; D020246:Venous Thrombosis / Q000235:genetics*
chemical_list: D000017:ABO Blood-Group System; C095381:factor V Leiden; D005165:Factor V; D011516:Prothrombin