Association of CTLA4+49 A/G polymorphism with type 1 diabetes in Tunisian population
Benmansour Jihen, Stayoussef Mouna, Almawi Wassim & Mahjoub Touhami
Type 1 diabetes (T1D) is a complex autoimmune disease. Several genetic loci have been implicated in the susceptibility to this illness. Evaluated was the role of the CTLA4 exon 1 A49G polymorphism and its role as a risk factor for T1D in our population. DNA from 120 patients with T1D and 96 control individuals were genotyped for CTLA4 exon 1 polymorphism by polymerase chain reaction (PCR) amplification-restriction enzyme analysis and PCR amplification that used sequence-specific primers, respectively. Patients were nonobese and <26 years old. The CTLA4 G allele was found to be more frequently present in patients with T1D (36.4%) as compared with its frequency in control individuals (18.5%). The GG genotype was also significantly higher among patients (17.6%) than in controls (7.2%). χ2 analysis and family-based association studies were performed and suggested the association of CTLA4 exon 1 G polymorphism with T1D (P=0.02). This study suggests that CTLA4 is a candidate susceptibility gene for T1D.