title: Val247Leu β2-glycoprotein-I allelic variant is associated with antiphospholipid syndrome: systematic review and meta-analysis.
abstract: BACKGROUND
  Previous studies have suggested that the possession of the Val/Val genotype of the Val247Leu polymorphism of the β(2)-glycoproteinI (β(2)-GPI) gene may be associated with antiphospholipid syndrome (APS), and, among patients with APS, with the production of anti-β(2)-GPI antibodies or the development of thrombosis. Given the controversial results reported, the aim of this work is to combine previous findings by means of a systematic review and a meta-analysis.
  
  
  METHODS
  We retrieved studies analyzing the genotype of the above-mentioned polymorphism among patients with APS by means of electronic database search. A meta-analysis was conducted in a random effects model and calculations of odds ratio (OR) and confidence intervals (CI) were done. Sensitivity analysis and tests for heterogeneity of the results were performed.
  
  
  RESULTS
  Eight previous studies analyzed the association of APS, anti-β(2)-GPI antibodies and/or thrombosis with the Val247Leu polymorphism. After meta-analysis, patients with APS had a significantly higher prevalence of the Val/Val genotype of this genetic variant when compared with controls (OR=2.04; 95% CI: 1.12, 3.73; P=0.02). Among patients with APS, those with anti-β(2)-GPI antibodies had a higher prevalence of this genotype (OR=1.73; 95% CI: 1.04, 2.87; P=0.03). No significant results were found for the presence of arterial or venous thrombosis.
  
  
  CONCLUSIONS
  Val/Val genotype of β(2)-GPI gene is associated with a significant excess risk to suffer from APS and, among patients with APS, to have anti-β(2)-GPI antibodies. No definite conclusions can be made regarding the association of this polymorphism with thrombosis among APS patients.
authors.affiliation: Department of Autoimmune Diseases, Institut Clínic de Medicina i Dermatologia, Hospital Clinic, Villarroel 170, 08036, Barcelona, Catalonia, Spain.
authors.forename: Antonio-Javier
authors.initials: AJ
authors.lastname: Chamorro
authors.forename: Miguel
authors.initials: M
authors.lastname: Marcos
authors.forename: José-Antonio
authors.initials: JA
authors.lastname: Mirón-Canelo
authors.forename: Ricard
authors.initials: R
authors.lastname: Cervera
authors.forename: Gerard
authors.initials: G
authors.lastname: Espinosa
mesh_terms: D016736:Antiphospholipid Syndrome / Q000097:blood / Q000235:genetics / Q000276:immunology*; D001323:Autoantibodies / Q000096:biosynthesis / Q000097:blood; D005787:Gene Frequency / Q000276:immunology*; D014644:Genetic Variation / Q000276:immunology*; D005838:Genotype; D006801:Humans; D007930:Leucine / Q000235:genetics; D011110:Polymorphism, Genetic / Q000276:immunology*; D014633:Valine / Q000235:genetics; D053482:beta 2-Glycoprotein I / Q000235:genetics* / Q000502:physiology
chemical_list: D001323:Autoantibodies; D053482:beta 2-Glycoprotein I; D007930:Leucine; D014633:Valine