目的：探讨多巴胺D4受体(DRD4)基因启动子区的3个功能多态性与慢性抽动障碍是否存在相关性。方法：选取无亲缘关系的慢性抽动障碍患儿84例以及无亲缘关系的健康个体100例,后者作为对照组。提取静脉血白细胞基因组DNA,采用聚合酶链反应及等位基因特异性扩增技术检测DRD4基因启动子区-1240L/S,-616C/G和-521C/T3个功能位点的基因型。用SHEsis在线统计软件分析各位点等位基因、基因型、单倍型频率及其组间差异。结果：DRD4基因-616C/G的等位基因频率及其基因型频率在慢性抽动障碍组显著高于正常对照组(χ2=8.419,P<0.01;χ2=7.860,P<0.05),DRD4基因-1240L/S,-616C/G和-521C/T组成的单倍型LCT的频率在慢性抽动障碍组显著高于正常对照组(χ2=6.371,P<0.05)。结论：DRD4基因-616C/G的等位基因可能与慢性抽动障碍相关联,携带有DRD4基因-1240L/S,-616C/G和-521C/T组成的单倍型LCT的个体可能更易患慢性抽动障碍。

OBJECTIVE: To study a possible association between the three functional polymorphisms in the promoter region of dopamine D4 receptor (DRD4) gene and chronic tic disorder. METHODS: Genomic DNA was isolated from the venous blood leukocytes of 84 unrelated patients with chronic tic disorder (Study group) and 100 healthy unrelated individuals (Control group). Polymorphisms of DRD4, -1240L/S, -616C/G and -521C/T, were genotyped by the allele-specific primer (ASP) PCR. Genotype, allele and haplotype frequencies were analysed by SHEsis online. RESULTS: There were significant differences in both allele and genotype frequencies (χ~2 =8.419, P<0.01;χ~2=7.860, P<0.05 respectively) of DRD4-616C/G between the Study and the Control groups. Haplotypic frequencies of LCT (-1240L/S, -616C/G, -521C/T) in the Study group were noticeably higher than in the Control group (χ~2 =6.371, P<0.05). CONCLUSIONS: There is an association between the DRD4-616C/G polymorphism and chronic tic disorder. The individuals with haplotype LCT (-1240L/S, -616C/G, -521C/T) are susceptible to this disorder.