title: Association of IRF5 gene polymorphisms with rheumatoid arthritis in a Tunisian population.
abstract: OBJECTIVE
  A strong genetic association of rheumatoid arthritis (RA) with the interferon regulatory factor 5 (IRF5) gene has been described previously in a Swedish population, although this result was not confirmed in a French population. We undertook an association study between IRF5 and the RA phenotype, as well as a study with serological markers of RA, in a Tunisian population.
  
  
  METHODS
  A single-nucleotide polymorphism (SNP; rs2004640) was genotyped using a Taqman 5' allelic discrimination assay on an ABI 7500 real-time polymerase chain reaction (PCR) instrument in 140 RA patients and 185 controls. Rheumatoid factor (RF) and anti-citrullinated protein/peptide antibodies (ACPA) were determined by enzyme-linked immunosorbent assay (ELISA). Association was assessed based on the chi(2) test and odds ratios (ORs) with 95% confidence intervals (CIs).
  
  
  RESULTS
  The frequency of the TT genotype of the IRF5 SNP rs2004640 differed significantly between patients and controls (p = 0.01). This difference was greater when a subgroup of patients with another 'autoimmune' disorder was considered (p = 0.007). A weak but significant association was also found in a subgroup of patients who were positive for ACPA (p = 0.04) or erosion (p = 0.01).
  
  
  CONCLUSIONS
  Our results indicate that the TT genotype of the IRF5 (rs2004640) dimorphism is associated with RA in a Tunisian population.
authors.affiliation: Laboratory of Human Molecular Genetics, Faculty of Medicine, Center of Biotechnology, Sfax, Tunisia. abdellatifmaalej@yahoo.fr
authors.forename: A
authors.initials: A
authors.lastname: Maalej
authors.forename: M Ben
authors.initials: MB
authors.lastname: Hamad
authors.forename: A
authors.initials: A
authors.lastname: Rebaï
authors.forename: V H
authors.initials: VH
authors.lastname: Teixeira
authors.forename: Z
authors.initials: Z
authors.lastname: Bahloul
authors.forename: S
authors.initials: S
authors.lastname: Marzouk
authors.forename: N R
authors.initials: NR
authors.lastname: Farid
authors.forename: H
authors.initials: H
authors.lastname: Ayadi
authors.forename: F
authors.initials: F
authors.lastname: Cornelis
authors.forename: E
authors.initials: E
authors.lastname: Petit-Teixeira