CTLA-4基因外显子1A/G49多态性与1型糖尿病的相关性研究

目的 探讨细胞毒性T淋巴细胞相关抗原4（CTLA－4）基因外显子1的49位点A／G多态性与中国汉族人1型糖尿病（DM）的关系。方法 采用多聚酶链式反应限制性片段长度多态性（PCR－RFLP）技术对33例典型1型DM患者、57例成人晚发自身免疫性糖尿病患者（LADA)和84例健康对照者分析CTLA－4基因外显子1的49位点基因型。结果 1型DM患者的CTLA－4／G^49等位基因频率显著高于对照组（P=0.0005)，而典型1型DM和LADA两组间无显著性差异（P＝0.097)；ICA和GADAb阳性率与G^49无明显相关性（分别为P＝0.065,P=0.066)。结论 CTLA－4基因外显子1多态性与中国汉族人1型DM有关，G^49等位基因是1型DM的独立危险因素之一。

The relationships between CTLA-4 gene exon I A/G49 polymorphism and type 1diabetes mellitus

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.