Cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) has an inhibitory function on T cells and is critical for the induction of peripheral tolerance. CTLA-4 +49 G allele affects the CTLA-4 function and has been reported to be correlated with a higher risk of various autoimmune diseases including type 1 diabetes (TIDM). The present study was conducted to investigate the association between the polymorphism of the CTLA-4 exon 1 +49 A/G and susceptibility to TIDM in Sanandaj population, a Kurdish city in the west of Iran. The +49 A/G polymorphism was analyzed in 64 patients with TIDM, 60 patients with type 2 diabetes (T2DM ) and 107 control subjects with no history of autoimmune disease using PCR-RFLP method. All populations (controls, T2DM and TIDM) were in Hardy-Weinberg equilibrium ( p; 0.892003, 0.75897 and 0.168063, respectively). There was significant CTLA-4 +49 G allele difference between TIDM with control (p=0.002163) and T2DM subjects ( p=0.008504). No significant difference was found between T2DM and control subjects regarding the distribution of the CTLA-4 +49 G allele. Our findings revealed a significant association of CTLA-4 exon 1 49 A/G polymorphism with the increase risk of T1DM in the Iranian Kurdish population. Financial support for this research was provided by the Research Department of the Kurdistan University of Medical Sciences, Kurdistan, Iran.
