IT15基因△2642多态性与亨廷顿病发病年龄的相关性

Study on relationship between delta 2642 genotypes in IT15 gene and age of onset of Huntington disease

目的 探讨IT15基因△2642多态性位点的基因型对亨廷顿病（Huntington disease，HD）发病年龄的影响。方法 采用聚合酶链反应-限制性片段长度多态性（PCR-RFLP）结合聚丙烯酰胺凝胶电泳（PAGE）技术及银染法，检测29例已行基因诊断的HD患者和38名健康对照者的IT15基因△2642多态性位点基因型，比较2组间△2642基因型分布，分析△2642基因型与HD发病年龄之间的关系。结果 两组均未检测到B／B基因型。△2642基因型A／A和A／B在HD组分布频率分别为65．5％和34．5％，在对照组分布频率分别为92．1％和7．9％（Х^2=7．435，P=0．006）。等位基因B在HD患者的频率分布高于对照组（分别为17．2％、3．9％，OR=5．07，95％CI 1．47—15．12，P=0．010）。A／B型和A／A型HD患者CAG重复次数差异无统计学意义（P=0．188）。HD组中基因型A／B患者发病年龄[（37．33±6．46）岁]较基因型A／A患者[（47．10±10．86）岁]早，差异有统计学意义（t=2．491，P=0．019）。结论IT15基因△2642基因型可能影响HD发病年龄，基因型A／B患者的发病年龄较基因型A／A患者提前。

Objective To detect the relationship between the genotypes of the 2642 deletion polymorphism （delta 2642） in IT15 gene and the age of onset of Huntington disease （HD）. Methods Peripheral blood samples were collected from 29 patients with HD and 38 gender- and age-matched controls. All patients with HD were diagnosed by gene diagnosis. The CAG tfinucleotide repeats of the 29 patients with HD outnumbered 40. Polymerase chain reaction-restriction fragment length polymorphism and polyacrylamide gel electrophoresis technique were used to detect the genotypes of delta 2642. Results No B/B genotype was detected in both 2 groups. The genotype frequencies of A/A and A/B in the IT15 delta 2642 polymorphism was 65.5% and 34.5% in HD patients,92. 1% and 7. 9% in the controls respectively （Х^2 = 7. 435, P =0. 006）. The frequency of the B allele was 17.2% in the HD group and 3.9% in the control group （P =0. 010, OR = 5.07, 95% CI 1.47-15.12）. Analysis showed no significant difference between A/A genotype patients and A/B genotype patients for CAG trinucleotide repeats （P = 0. 188 ）. HD patients with A/B genotype （37.33 ± 6.46） had an earlier onset than the patients with A/A genotype （47. 10 ± 10.86, t = 2. 491, P =0. 019 ）. Conclusions These data demonstrated that variations in IT15 delta 2642 polymorphisms may be a genetic factor that influences the variability in HD age of onset. HD patients with delta 2642 A/B genotype have an earlier onset than the patients with A/A genotype.