title: Genetics in rheumatoid arthritis beyond HLA genes: what meta-analyses have shown?
abstract: OBJECTIVE
  Rheumatoid arthritis (RA) is a complex disorder with many genetic and environmental factors to account for disease susceptibility. Individual genetic association studies usually suffer from small sample size leading to biased results of polymorphisms association with RA liability. Therefore, meta-analyses seem to resolve this limitation, up to a point, increasing the power of statistical analyses. In this review, we summarize the current knowledge of non-HLA genetic factors contributing to RA predisposition based on meta-analyses.
  
  
  METHODS
  Using the key words: rheumatoid arthritis, meta-analysis, and polymorphism, we searched the PubMed database for the associated articles. Up to the middle of November 2012, seventy-nine articles fulfilled the criteria and highlighted the current findings on the genetic factors contributing to RA susceptibility.
  
  
  RESULTS
  The association with RA was confirmed for 32 gene polymorphisms, being population specific in some cases. However, meta-analyses did not confirm an association in case of 16 gene variants, previously studied in individual studies for their association with RA.
  
  
  CONCLUSIONS
  The use of bioinformatics tools and functional studies of the summarized implicated genes in RA pathogenesis could shed light on the molecular pathways related to the disorder, helping to the development of new drug targets for a better treatment of RA.
authors.affiliation: Laboratory of General Biology and Genetics, Medical School, Aristotle University of Thessaloniki, Greece.
authors.forename: Anthoula
authors.initials: A
authors.lastname: Chatzikyriakidou
authors.forename: Paraskevi V
authors.initials: PV
authors.lastname: Voulgari
authors.forename: Alexandros
authors.initials: A
authors.lastname: Lambropoulos
authors.forename: Alexandros A
authors.initials: AA
authors.lastname: Drosos
mesh_terms: D001172:Arthritis, Rheumatoid / Q000235:genetics*; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006680:HLA Antigens / Q000235:genetics*; D006801:Humans; D015201:Meta-Analysis as Topic; D011110:Polymorphism, Genetic
chemical_list: D006680:HLA Antigens
keywords: Gene; Meta-analysis; Polymorphism; Rheumatoid arthritis