【摘要】 目的 检测脆性X染色体综合征智力低下基因FMR1中(CGG)n拷贝数的多态性。 方法 采用PCR结合序列胶银染法、Southern blot杂交分析法，对299条表型正常的湖南省人群X染色体FRAXA位点(CGG)n拷贝数的多态性及分布频率进行了测定和验证。 结果 显示其范围为20～40，高峰为28，PCR-序列分析银染法结果与Southern blot法结果完全一致。 结论 检测了湖南省人群X染色体FRAXA位点(CGG)n拷贝数的多态性;运用PCR-序列分析胶银染法快速、直接、简便、实用，适合脆性X综合征的大规模群体筛查。

    【关键词】 脆性X综合征 FMR1 (CGG)n PCR

    The study of the unsteady DNA repeat located in the mentally retardant FMR1gene of fragile X

    Li Binyuan，Ma Yun，He Shuya，et al.

    The Educational and Research Room of Biochemical and Molecule Biology，Nanhua University，Henyang，Hunan421001.

    【Abstract】 Objective To detect the polymorphism of CGG repeats located in the mentally retardant FMR1gene of fragile X.Methods To detect and test the polymorphism and frequency of CGG repeats located in the FRAX-A region come from299chromosome of normal hunan pupulations.Results The normal range of CGG repeats is20-40 ......