title: Association between the PTPN22 +1858 C/T polymorphism and psoriatic arthritis.
abstract: BACKGROUND
  The purpose of the present study was to investigate the frequency of the PTPN22 +1858 C/T single nucleotide polymorphism (SNP) (rs 2476601), previously shown to be associated with several autoimmune diseases, in patients with psoriatic arthritis (PsA) in comparison with population based controls.
  
  
  METHODS
  A total of 291 patients (145 male/146 female, mean age (± S.D.) 52.2 (± 13.1) years) with PsA were examined clinically, by standard laboratory tests and their DNA was genotyped for the SNP rs2476601 (PTPN22 +1858 C/T). Allelic frequencies were determined and compared with 725 controls.
  
  
  RESULTS
  Carriage of the risk allele, PTPN22+1858T, showed a significant association with patients with PsA compared with controls (χ2 = 6.56, P = 0.010, odds ratio (OR) 1.49; 95% confidence interval (CI) 1.10 to 2.02). A significantly higher proportion of carriers of the risk allele (T) had significantly more deformed joints (n ± SEM) (5.9 ± 1.2 vs 2.8 ± 0.5; P = 0.005).
  
  
  CONCLUSIONS
  In this study the +1858T allele of the PTPN22 gene, known to be associated with several autoimmune diseases, was associated with PsA. The finding of significantly more joints with deformities among carriers of the T variant could indicate a more aggressive phenotype of disease.
authors.affiliation: Department of Public Health and Clinical Medicine, Rheumatology, University Hospital, SE-901 85 Umeå, Sweden. kristina.juneblad@vll.se
authors.forename: Kristina
authors.initials: K
authors.lastname: Juneblad
authors.forename: Martin
authors.initials: M
authors.lastname: Johansson
authors.forename: Solbritt
authors.initials: S
authors.lastname: Rantapää-Dahlqvist
authors.forename: Gerd-Marie
authors.initials: GM
authors.lastname: Alenius
mesh_terms: D015535:Arthritis, Psoriatic / Q000235:genetics*; D016022:Case-Control Studies; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D054596:Protein Tyrosine Phosphatase, Non-Receptor Type 22 / Q000235:genetics*
chemical_list: C516765:PTPN22 protein, human; D054596:Protein Tyrosine Phosphatase, Non-Receptor Type 22