title: The protein tyrosine phosphatase non-receptor type 22 C1858T polymorphism is a joint susceptibility locus for immunthyroiditis and autoimmune diabetes.
abstract: BACKGROUND
  The lymphoid tyrosine phosphatase (LYP) encoded by the protein tyrosine phosphatase non-receptor type 22 (PTPN22) gene is a strong inhibitor of T cells. The single nucleotide polymorphism (SNP) C1858T within the PTPN22 gene was recently associated with autoimmune thyroid disease (AITD) and type I diabetes (T1D). The purpose of this study was to examine the joint association of this polymorphism with the co-occurrence of AITD and T1D.
  
  
  METHODS
  In this association study, 310 white subjects were genotyped for the C1858T polymorphism. The study population included 70 patients with both AITD and T1D (AITD+T1D), 70 patients with AITD only, 70 patients with T1D only, and 100 healthy controls. Patients with both AITD and T1D, and controls were also typed for HLA-DRB1. PTPN22 C1858T genotyping was performed by minisequencing. For HLA-DRB1 typing, polymerase chain reaction (PCR) sequence-specific oligonucleotide probes were used.
  
  
  RESULTS
  The PTPN22 1858 minor T-allele frequency was strongly increased in patients with AITD+T1D (23.6%) compared with controls (8.0%, pc<0.001), with patients with AITD only (8.6%, pc=0.006), or with T1D only (10.7%, pc=0.028). T-allele carriers were also more frequently present in the group with AITD+T1D versus controls (41.4% vs. 14.0%, OR=4.35, 95% CI=2.08-9.09), AITD (17.1%, OR=3.42, 95% CI=1.56-7.48), and T1D (21.4%, OR=2.59, 95% CI=1.23-5.45). Especially in subjects with Hashimoto's thyroiditis (HT)+T1D, T-allele carriers were mostly frequent (50% vs. 14%, OR=6.14, 95% CI=2.62-14.38, pc<0.001). Considering all included patients with AITD, T-allele carriers were 29.3% vs. 14.0% in controls (p=0.008, OR=2.54, 95% CI=1.30-4.98). Patients carrying the PTPN22 1858 T allele had a twofold increased frequency of the HLA-DRB1*03 allele (64.7% vs. 37.3%, pc=0.034).
  
  
  CONCLUSIONS
  The PTPN22 gene is a joint susceptibility locus for AITD (especially HT) and T1D.
authors.affiliation: Department of Medicine I, Gutenberg University, Mainz, Germany.
authors.forename: Georg
authors.initials: G
authors.lastname: Dultz
authors.forename: Nina
authors.initials: N
authors.lastname: Matheis
authors.forename: Manuela
authors.initials: M
authors.lastname: Dittmar
authors.forename: Bernd
authors.initials: B
authors.lastname: Röhrig
authors.forename: Klaus
authors.initials: K
authors.lastname: Bender
authors.forename: George J
authors.initials: GJ
authors.lastname: Kahaly
mesh_terms: D000293:Adolescent; D000328:Adult; D000595:Amino Acid Sequence; D001323:Autoantibodies; D001483:Base Sequence; D002648:Child; D003922:Diabetes Mellitus, Type 1 / Q000150:complications / Q000235:genetics*; D020022:Genetic Predisposition to Disease; D006801:Humans; D008875:Middle Aged; D008969:Molecular Sequence Data; D017354:Point Mutation; D020641:Polymorphism, Single Nucleotide; D054596:Protein Tyrosine Phosphatase, Non-Receptor Type 22 / Q000235:genetics*; D013961:Thyroid Gland / Q000276:immunology; D013967:Thyroiditis, Autoimmune / Q000150:complications / Q000235:genetics*
chemical_list: D001323:Autoantibodies; C516765:PTPN22 protein, human; D054596:Protein Tyrosine Phosphatase, Non-Receptor Type 22