The association of lymphoid protein tyrosine phosphatase non-receptor 22 (PTPN22) gene polymorphism with Egyptian type 1 diabetes risk

Background: Type 1 diabetes (T1D) is a T-cell mediated autoimmune disease. Protein tyrosine phosphatase non-receptor type 22 (PTPN22) gene is a powerful inhibitor of T-cell activation. The single nucleotide polymorphism (SNP) of PTPN22 1858C>T is a gain-of-function increasing reactivity of immune system and risk of autoimmune diseases. Our aim was to evaluate PTPN22 1858C>T gene polymorphism in T1D and diabetic complications risk in Egyptian pediatric patients. Methods: PTPN22 1858C>T gene polymorphism was analyzed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay in 50 T1D pediatric patients and 100 healthy control subjects matched on age and sex. Results: The frequency of wild genotype CC was statistically higher among controls (92%) versus T1D patients (74%), while the mutant CT/TT genotypes were statistically higher among patients (26%) versus controls (8%) (p=0.003). Higher mutant T allele frequency in patients (17%) versus controls (4%) was found, while C allele showed higher frequency among controls (96%) versus patients (83%) (P < 0.001). Mutant genotypes CT/TT showed statistically significant higher frequencies among T1D patients with hypoglycaemic attacks, fundus abnormalities and peripheral neuropathy (p=0.029, p=0.001 and p=0.002), respectively. Conclusion: Our study revealed the role of PTPN22 1858C>T gene polymorphism in T1D; thus, it may be concidered as a genetic risk factor in T1D and diabetic complications in Egyptian pediatric patients.