The CTLA4 -819 C/T and +49 A/G dimorphisms are associated with Type 1 diabetes in Egyptian children

BACKGROUND: Type 1 diabetes (T1D) is an organ-specific autoimmune disease characterized by T cell-mediated destruction of pancreatic islets. T cell proliferation is negatively regulated by cytotoxic lymphocyte antigen-4 (CTLA-4). CTLA-4 polymorphisms are associated with T1D in some but not all populations. AIMS: The study was conducted to investigate the association of the C-819T and A+49G single nucleotide polymorphisms (SNP) of CTLA-4 gene in T1D patients in the Egyptian population. METHODS: The association of the C-819T SNP in intron 1 and A+49G SNP in exon 1 of the CTLA-4 gene with T1D were investigated in 396 Egyptian patients ≤14 years old and 396 control subjects >24 years old, with the same ratio of males to females in both groups. The diagnosis of T1D was made on the basis of ketoacidosis or ketosis with severe symptoms of acute onset at presentation and continuous dependence on insulin. Controls were negative for anti-GAD antibodies and were greater than 24 years of age. Genotyping was performed using single strand conformation polymorphism (SSCP), temperature gradient gel electrophoresis (TGGE), and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). RESULTS: The results demonstrated an association of the C-819T and A+49G SNPs in the CTLA-4 gene with T1D patients (P=0.0047) and (P=0.000575), respectively. Moreover, this association was stratified by gender and age to female patients with age at onset 0-5 years old (P=0.0186) and (P=0.00115) more than male patient with the age at onset 0-5 years old (P= 0.3120) and (P=0.345161), respectively. CONCLUSION: The results support an association of the C-819T and A+49G SNPs in the CTLA-4 gene with Egyptian children, specifically, females of onset age 0-5 years old.