1个脆性X综合征家系的FMR1基因CGG重复及甲基化状态分析  

Analysis of CGG duplication and methylation status of FMR1 gene in a fragile X syndrome family

作　　者：钟青燕[1,2] 刘晓丽 罗世强[1,2,3] 袁德健 王敬仁 王秋华[1,2] 黄钧 严提珍[1,2,3] ZHONG Qingyan;LIU Xiaoli;LUO Shiqiang;YUAN Dejian;WANG Jingren;WANG Qiuhua;HUANG Jun;YAN Tizhen(Department of Medical Genetics,Liuzhou Maternity and Child Health Care Hospital&Affiliated Maternity Hospital and Affiliated Children′s Hospital of Guangxi University of Science and Technology,Liuzhou 545001,Guangxi,China;Liuzhou Key Laboratory of Birth Defect Prevention and Control,Liuzhou Maternity and Child Health Care Hospital&Affiliated Maternity Hospital and Affiliated Children′s Hospital of Guangxi University of Science and Technology,Liuzhou 545001,Guangxi,China;.Liuzhou Institute of Reproduction and Genetics,Liuzhou Maternity and Child Health Care Hospital&Affiliated Maternity Hospital and Affiliated Children′s Hospital of Guangxi University of Science and Technology,Liuzhou 545001,Guangxi,China)

机构地区：[1]柳州市妇幼保健院&广西科技大学附属妇产医院、儿童医院医学遗传科,广西柳州545001 [2]柳州市妇幼保健院&广西科技大学附属妇产医院、儿童医院柳州市出生缺陷预防与控制重点实验室,广西柳州545001 [3]柳州市妇幼保健院&广西科技大学附属妇产医院、儿童医院柳州市生殖与遗传研究所,广西柳州545001

出　　处：《临床检验杂志》2022年第6期438-443,共6页Chinese Journal of Clinical Laboratory Science

基　　金：广西壮族自治区卫生和计划生育委员会科研课题(Z2016549);柳州市科技创新能力与条件建设项目(2018AF10501);广西医学高层次人才培养计划资助(G202003028);柳州市个十百人才工程专项资金资助;广西壮族自治区卫生健康委员会自筹经费科研课题(Z20190789)。

摘　　要：目的应用PCR微流控芯片毛细管电泳联合MS-MLPA技术对1个脆性X综合征家系进行CGG重复序列和甲基化状态分析,探讨FMR1基因甲基化程度和临床表型的关系。方法应用PCR微流控芯片毛细管电泳法对该家系22个成员进行FMR1基因CGG重复数检测,采用甲基化特异性多重连接依赖探针扩增(MS-MLPA)技术检测FMR1基因启动子区域CpG岛的甲基化情况,并用Southern印迹杂交技术对全突变患者进行验证。结果22个家系成员中检出前突变携带者8例,全突变女性携带者1例,脆性X综合征男性患者4例。MS-MLPA分析发现女性正常型和前突变携带者的甲基化比值分别为0.25~0.48(中位数0.33)和0.33~0.46(中位数0.38),两组间差异无统计学意义(t=0.095,P>0.05),1例女性全突变携带者甲基化比值为0.52,高于正常型和前突变携带者,4例男性全突变患者甲基化比值均>0.64,中度智力障碍组和重度智力障碍组之间甲基化比值差异无统计学意义(t=0.58,P>0.05)。结论CGG重复数检测和甲基化分析可为脆性X综合征家系成员提供准确全面的分子诊断;男性患者临床表型和甲基化程度相关。Objective To investigate the CGG repeat sequence and methylation status of a family with fragile X syndrome by polymerase chain reaction(PCR)microfluidic chip-capillary electrophoresis combined with methylation-specific multiplex ligation-dependent probe amplification(MS-MLPA)technique,and analyze the relationship between the methylation degree of FMR1 gene and clinical phenotype.Methods The number of CGG repeats of FMR1 gene in 22 members of the family was detected by PCR microfludic chip-capillary electrophoresis.The methylation of CpG island in the promoter region of FMR1 gene was detected by the MS-MLPA technique.The full mutation patients were verified by Southern blot hybridization.Results Among the 22 family members,8 premutation carriers,1 full mutation female carrier,and 4 fragile X syndrome male patients were detected.MS-MLPA analysis showed that the methylation ratios of normal females and premutation carriers were 0.25-0.48(median 0.33)and 0.33-0.46(median 0.38),respectively,and that there was no significant difference between them(t=0.095,P>0.05).The methylation ratio of a female full mutation carrier was 0.52,which was higher than that of normal type and premutation carriers.The methylation ratios of 4 male full mutation patients were all>0.64.There was no significant difference in the methylation ratios between moderate and severe intellectual disabilities(t=0.58,P>0.05).Conclusion The detection of CGG repeats and methylation analysis can provide accurate and comprehensive molecular diagnosis for family members of fragile X syndrome.The clinical phenotype of male patients is correlated with the degree of methylation.

关 键 词：脆性X综合征 FMR1基因 甲基化 毛细管电泳 甲基化特异性多重链接依赖探针扩增 

分 类 号：R446[医药卫生—诊断学] R394[医药卫生—临床医学]