title: Association of the PTPN22 R620W polymorphism with anti-topoisomerase I- and anticentromere antibody-positive systemic sclerosis.
abstract: OBJECTIVE
  To determine any associations of the PTPN22 R620W single-nucleotide polymorphism (SNP) with systemic sclerosis (SSc) or with anticentromere antibody (ACA)-positive or anti-topoisomerase I (anti-topo I) antibody-positive SSc, in a case-control study of US white, black, Hispanic, and Choctaw Indian individuals.
  
  
  METHODS
  A total of 850 white, 130 black, 120 Hispanic, and 20 Choctaw Indian patients with SSc were compared with 430 white, 164 black, 146 Hispanic, and 76 Choctaw Indian control subjects, respectively. All subjects were living in the US. PTPN22 SNP (rs2476601) genotyping was performed by TaqMan 5' allelic discrimination assay and pyrosequencing.
  
  
  RESULTS
  The PTPN22 CT/TT genotype showed significant association with anti-topo I antibody-positive SSc in white patients (odds ratio [OR] 2.21, 95% confidence interval [95% CI] 1.3-3.7) and with ACA-positive white patients with SSc (OR 1.70, 95% CI 1.1-2.7). Frequency of the PTPN22*T allele also showed significant association with anti-topo I antibody-positive SSc in white patients (OR 2.03, 95% CI 1.3-3.2). When data for patients in the 3 ethnic groups (black, white, and Hispanic) were combined, a significant association with both genotype and allele frequencies was observed, suggesting a trend toward association in ACA-positive and anti-topo I antibody-positive SSc. Stepwise logistic regression analysis (controlled for the confounding effects of sex and race) showed that the PTPN22 CT/TT genotype was associated with a significantly higher risk of SSc compared with the CC genotype (for patients with SSc, OR 1.64, 95% CI 1.2-2.2; for ACA-positive patients with SSc, OR 1.63, 95% CI 1.0-2.6; for anti-topo I antibody-positive SSc, OR 2.33, 95% CI 1.5-3.7).
  
  
  CONCLUSIONS
  Our results indicate that the PTPN22 R620W polymorphism is associated with ACA-positive and anti-topo I antibody-positive subsets of SSc and represents a risk factor in both white patients and black patients. The association of subsets of SSc with the PTPN22 R620W polymorphism further strengthens the classification of SSc within the spectrum of autoimmune diseases and strongly suggests the involvement of common susceptibility genes and similarly disordered immunoregulatory pathways.
authors.affiliation: University of Texas Health Science Center at Houston, TX 77030, USA. pravit.gourh@uth.tmc.edu
authors.forename: Pravitt
authors.initials: P
authors.lastname: Gourh
authors.forename: Filemon K
authors.initials: FK
authors.lastname: Tan
authors.forename: Shervin
authors.initials: S
authors.lastname: Assassi
authors.forename: Chul W
authors.initials: CW
authors.lastname: Ahn
authors.forename: Terry A
authors.initials: TA
authors.lastname: McNearney
authors.forename: Michael
authors.initials: M
authors.lastname: Fischbach
authors.forename: Frank C
authors.initials: FC
authors.lastname: Arnett
authors.forename: Maureen D
authors.initials: MD
authors.lastname: Mayes
mesh_terms: D001323:Autoantibodies / Q000097:blood; D002503:Centromere / Q000276:immunology*; D004264:DNA Topoisomerases, Type I / Q000276:immunology*; D005260:Female; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D008297:Male; D016017:Odds Ratio; D020641:Polymorphism, Single Nucleotide; D054596:Protein Tyrosine Phosphatase, Non-Receptor Type 22; D017027:Protein Tyrosine Phosphatases / Q000235:genetics*; D044469:Racial Groups / Q000235:genetics; D012307:Risk Factors; D012595:Scleroderma, Systemic / Q000201:enzymology / Q000235:genetics* / Q000276:immunology; D013781:Texas
chemical_list: D001323:Autoantibodies; C516765:PTPN22 protein, human; D054596:Protein Tyrosine Phosphatase, Non-Receptor Type 22; D017027:Protein Tyrosine Phosphatases; D004264:DNA Topoisomerases, Type I