Analysis of cytotoxic T lymphocyte antigen-4 (CTLA-4) exon 1 polymorphism in patients with type 1 diabetes mellitus in a Turkish population.

Recent studies have described linkage and association between cytotoxic T-lymphocyte antigen-4 (CTLA-4) gene polymorphism and type 1 diabetes mellitus (DM1) in some ethnic populations, but not others. This finding suggests that CTLA-4 gene association with DM1 may be influenced by the racial composition of the population. Thus, it is important to study the polymorphism of the CTLA-4 gene in different ethnic groups. In this case-control association study, the CTLA-4 gene exon 1 A/G polymorphism was analyzed in 48 children with DM1 and 80 healthy controls using polymerase chain reaction-restriction fragment length polymorphism analysis. The possible interaction of the CTLA-4 gene polymorphism with the presence of established genetic markers (HLA-DR genotyping) was also evaluated in 29 patients. The results of the present study do not suggest an association of the known polymorphism in exon 1 of the CTLA-4 gene with DM1 in this Turkish population, and G-allele containing CTLA-4 genotypes were not preferentially associated with age at clinical presentation or with presence of other genetic (HLA-DR3 or -DR4) markers of DM1.