脆性X综合征FMR1基因CGG重复序列与甲基化的检测

Detection of the CGG repeats and methylation of Fragile X mental retardation gene 1(FMR1)

目的建立一种快速、可靠的脆性X综合征的群体筛查方法。方法应用热启动PCR和甲基化特异性PCR(MS-PCR)方法对62例智力低下儿童、12例父母外周血液以及5例高危胎儿的脐带血中FMR1基因CGG重复序列与甲基化状态进行检测。结果采用热启动PCR方法检测79例标本,77例标本的CGG重复数在21～40之间,与正常对照组无明显差异;2例标本未扩增出明显条带。采用MS-PCR方法检测出2例FMR1基因甲基化但CGG重复数在正常范围的患者。结论应用热启动PCR结合MS-PCR方法检测FMR1基因CGG重复数和甲基化,能提高诊断效率,可作为筛查脆性X综合征的首选方法。

Objective： To establish a time-efficient and sensitive method for screening the CGG repeats and methylation of Fragile X mental retardation gene 1（FMR1）.Methods： The Hot-start PCR and methylation specific PCR（MS-PCR） were used to detect the CGG repeats and methylation in FMR1 gene of the Mental Retardation（MR） children,their parents and fetus of pregnancy women who had given birth MR children.Results： Detected by the Hot-start PCR,CGG repeats number in FMR1 gene of MR children and the control group were 21-40,15-34 respectively and no significant difference were observed between two groups.The CGG repeats number in FMR1 gene of two MR children did not be detected.However,the two MR children were observed methylated FMR1 gene but normal CGG repeats by MS-PCR.Conclusion： The Hot-start PCR and MS-PCR are efficient and sensitive methods for screening fragile X syndrome.