ABSTRACT
Objective To investigate the association of cytotoxic T lymphocyte associated antigen 4(CTLA 4) gene polymorphism with type 1 diabetes in Chinese Han population.Methods The A/G phenotype at position 49 of the CTLA 4 gene exon 1 was determined by polymerase chain reaction restriction fragment length polymorphism(PCR RFLP)method in 33 typical type 1 diabetes patients,57 latent autoimmune diabetes in adults(LADA) patients and 84 healthy control subjects of Chinese Han.Results The frequency of the CTLA 4/G 49 phenotype was significantly higher in type 1 diabetes patients than in control subjects(55.6% vs 36.9%, respectively, P =0.0005),but there was no significant difference between typical type 1 DM and LADA groups. Neither the presence nor the absence of G 49 allele influenced the occurrence of islet autoantibody(ICA) and glutamate decarboxylase antibody(GADAb).Conclusion The polymorphism of CTLA 4 gene exon1 confers susceptibility to type 1 diabetes. This association is independent of ICA and GADAb.