正常人群及3个智力低下家系FMR1基因CGG重复序列检测与分析

Detection of variation of CGG repeats located in the FMR1 gene normal populations and individuals from 3 mental retardation families

目的:检测、分析脆性X综合征致病基因FMR1第1外显子的三核苷酸CGG重复序列在正常人群及智力低下家系中的分布情况。方法:采用PCR扩增技术和聚丙烯酰胺凝胶电泳技术方法,对随机抽取的154名中国汉族正常人(男73人、女81人)和3个智力低下家系有关成员FMR1基因CGG重复序列进行分析。结果:共检测到19种等位基因,CGG重复变异范围n=12～40,最大频率等位基因n=29,频率为16.2%。3个智力低下家系中未检测到CGG重复序列异常扩增。结论:在中国正常人群体中FMR1基因CGG重复序列变异分布与高加索人群体有差异;所检测的3个家系智力低下症状不是由于FMR1基因CGG重复异常扩增所致。

Objective: To detect and analyze the variation of CGG repeats located in the FMR1 gene in normal Chinese population and individuals from 3 mental retardation families. Methods: PCR and polyacrylamide gel electrophoresis were used to analyze the variation of CGG repeats located in the FMR-1 gene in randomly collected normal Chinese populations and individuals in 3 MR families. Results: 19 alleles were observed with the CGG repeat number ranging from 12 to 40, and the most common CGG repeat allele in the normal Chinese population is 29(16.2%). No unusual expansion of CGG repeat was observed in 3 MR families. Conclusion: The variation of CGG repeats located in the FMR1 gene in normal Chinese population is different from that in Caucasians. The mental retardation symptoms of 3 families detected were not caused by unusual expansion of CGG repeats loated in the FMR1 gene.