The -1123G>C variant of PTPN22 gene promoter is associated with latent autoimmune diabetes in adult Chinese Hans.

The protein tyrosine phosphatase non-receptor 22 (PTPN22) gene encodes for lymphoid protein tyrosine phosphatase. Recent studies demonstrated the association between the +1858T, -1123G>C variants of PTPN22 gene and type 1 diabetes mellitus in Caucasian and Japanese populations. This study examined the relationship between the polymorphism of PTPN22 gene and latent autoimmune 1 diabetes in adults (LADA) in Chinese Hans. We studied 229 adult Chinese patients with LADA (LADA group) and 210 healthy volunteers (control group). The -1123G>C and +1858C>T polymorphisms of PTPN22 gene were determined by PCR-restriction fragment length polymorphism method. Further, genotypic/allelic frequencies and clinical characteristics were compared between two groups. There was a significant difference of frequencies of the -1123G>C polymorphism between LADA and control groups (OR = 1.99, 95% CI = 1.24-3.2; P = 0.001). However, no significant differences in the +1858C>T genotypic (CC, CT) and allelic (C, T) frequencies were found. Furthermore, the frequencies of the -1123 GC, CC genotype in male patients with LADA were significantly higher compared with male healthy volunteers (OR = 1.65, 95% CI = 1.21-2.26; P = 0.005). The analysis of covariance demonstrated no difference between glycosylated hemoglobin, body mass index, duration of diabetes, C-peptide, and GAD-Ab titer between the group carrying GC/CC and the group without allele C. In conclusion, the -1123G>C promoter polymorphism of PTPN22 gene, but not the +1858C>T variant, is associated with LADA in adult Chinese Hans.