title: Factor-V HR2 haplotype and thromboembolic disease.
abstract: OBJECTIVE
  The objective of this study is to evaluate the prevalence of HR2 polymorphism among patients with pulmonary embolism (PE) and healthy subjects.
  
  
  BACKGROUND
  Polymorphism in the factor V gene named HR2 has been described as a possible risk factor for venous thromboembolism (VTE) development. Contradictive results on this association have been reported.
  
  
  METHODS
  Eighty-five patients admitted for PE and 72 healthy subjects were included in the study. Thrombophilia screening using genetic tests for factor V Leiden (G1691A/Leiden and HR2 haplotype) and other genetic mutations were investigated.
  
  
  RESULTS
  Of 85 patients with PE, 20 (23.53%) carried the HR2 haplotype. Further, a majority of the patients with HR2 haplotype had recurrent venous thrombosis or PE (15 out of 20 patients). The HR2 haplotype was detected in 6 (8.3%) out of 72 healthy subjects. Patients had significantly higher HR2 haplotype frequency than healthy controls (P = 0.001). HR2 carriers had a three-fold increase in risk of developing PE (OR = 3.38, 95% CI = 1.27-8.96, P = 0.011). After adjustment for other tested defects for thrombophilia, HR2 haplotype was associated with increased risk of thromboembolic events (OR = 3.05, 95% CI = 1.11-8.35, P = 0.03). However, after adjustment for sex and age, HR2 polymorphism was no longer associated with the risk of thromboembolic event (OR = 1.22, 95% CI = 0.34-4.38, P = 0.76).
  
  
  CONCLUSIONS
  Our study does not support the notion that factor V HR2 haplotype might be a risk factor for thrombosis despite its high prevalence among patients with PE.
authors.forename: Aneta
authors.initials: A
authors.lastname: Aleksova
authors.forename: Milena
authors.initials: M
authors.lastname: Di Nucci
authors.forename: Marco
authors.initials: M
authors.lastname: Gobbo
authors.forename: Elena
authors.initials: E
authors.lastname: Bevilacqua
authors.forename: Paola
authors.initials: P
authors.lastname: Pradella
authors.forename: Kassem
authors.initials: K
authors.lastname: Salam
authors.forename: Giulia
authors.initials: G
authors.lastname: Barbati
authors.forename: Antonio
authors.initials: A
authors.lastname: De Luca
authors.forename: Luca
authors.initials: L
authors.lastname: Mascaretti
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Sinagra
mesh_terms: D000328:Adult; D004247:DNA / Q000235:genetics*; D005165:Factor V / Q000235:genetics* / Q000378:metabolism; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D006239:Haplotypes; D006801:Humans; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D011655:Pulmonary Embolism / Q000097:blood / Q000235:genetics*; D012189:Retrospective Studies
chemical_list: C095381:factor V Leiden; D005165:Factor V; D004247:DNA
keywords: HR2 polymorphism; pulmonary embolism; thrombophilia; venous thromboembolism