[Association of polymorphism of protein tyrosine phosphatase nonreceptor-22 gene with AITD]

To evaluate the association of PTPN22 gene polymorphism with autoimmune thyroid disease (AITD) in Chinese people and to analyze the relationship between SNP of CTLA-4 gene and SNP of PTPN22 gene.

149 patients with Graves' disease (GD) and 82 patients with Hashimoto's thyroiditis (HT) as well as 131 healthy people as controls were investigated. PTPN22 gene polymorphism +1858 C>T and CTLA-4 gene polymorphism 49A>G were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). PTPN22 gene polymorphism -1123G>C at promoter was genotyped by single allele-specific primer polymerase chain reaction (SASP-PCR).

(1) +1858C>T for PTPN22 gene was not polymorphic enough in patients and controls. (2) Statistic differences in alleles and genotype frequency of -1123G>C were observed between GD patients and controls (P=0.040, 0.013; OR=1.44, 2.33, respectively). (3) Differences in alleles and genotype frequency of 49A>G for CTLA-4 gene were observed in patients and controls. (4) Individuals with PTPN22 CC genotype and CTILA-4 G alleles had an increased risk of developing GD (OR=3.31, 95%CI: 2.69-8.89) compared with those with PTPN22 G alleles and CTLA-4 AA genotype.

-1123 G>C SNP of PTPN22 gene is associated with GD. There is coordination between PTPN22 CC genotype and CTLA-4 G alleles in the development of GD.