부산대학교 도서관

OBJECTIVEAlthough the polymorphisms of the cytotoxic T lymphocyte antigen 4 (CTLA4) gene have been shown to be associated with Type 1 diabetes in Caucasians, some conflicting results have been reported among subjects of different ethnic backgrounds. We examined a CTLA4 polymorphism and its relationship to human leucocyte antigen (HLA) genotypes and autoantibodies for glutamic acid decarboxylase 65 (GAD65) and IA-2 in Japanese children with Type 1 diabetes. SUBJECTS AND MEASUREMENTSThe study group consisted of 125 childhood-onset Japanese subjects (50 males, 75 females) with Type 1 diabetes. The CTLA4 A/G polymorphism at position 49 was analysed using a PCR-restriction fragment length polymorphism (PCR-RFLP) method. The HLA-DRB1 and DQB1 genotypes were defined by DNA analysis using PCR-sequence-specific oligonucleotide (PCR-SSO) probes. The GAD65 autoantibody (GAD65Ab) and IA-2 autoantibody (IA-2Ab) titres were measured using radioimmunoassay. RESULTSThe distribution of genotype frequencies differs between subjects with Type 1 diabetes (GG: 46%, AG: 50%, AA: 5%) and controls (GG: 39%, AG: 44%, AA: 17%) (P < 0·01). The frequency of the G allele is higher in the diabetes group than in the controls (P < 0·05). When the subjects were subdivided according to HLA genotype, the two major HLA high-risk groups, with DR9-DQ9 and DR4-DQ4, that are unique to Japanese populations showed no difference in their CTLA4 polymorphism frequencies. Although no association between the CTLA4 polymorphism and the prevalence of GAD65Ab was found, CTLA4 GG subjects that had been newly diagnosed (< 9 months) had significantly higher levels of autoantibodies than AG subjects (P < 0·01). The prevalence and titres of IA-2Ab were not associated with the CTLA4 polymorphism. CONCLUSIONSThe CTLA4 gene might confer a susceptibility to childhood-onset Type 1 diabetes in the Japanese population. The association between this CTLA4 polymorphism and the HLA genotype was similar for both... [ABSTRACT FROM AUTHOR]