基于毛细管电泳片段分析的MJD/SCA3基因诊断

Gene diagnosis of MJD/SCA3 based on fragment analysis with capillary electrophoresis

目的:建立并完善MJD/SCA3的基因诊断方法,研究临床表型和CAG重复次数的相关性。方法:应用毛细管电泳片段分析(STR分析)对MJD/SCA3基因内CAG重复次数进行精确分析,并采用测序予以验证。结果:王氏家系为SCA3家系,STR分析显示3例患者的CAG重复数目分别为69次、75次和68次。尽管王氏本人尚未出现临床表型,但通过基因诊断已经确认为患者,并明确其CAG重复次数。结论:毛细管电泳片段分析确实为一项简便和准确的STR分析方法,可为动态突变的遗传性疾病提供可靠的基因诊断,也可为相关疾病的临床诊断和遗传咨询提供科学可靠的实验依据。

Objective：To set up and optimize the method of gene diagnosis for MJD/SCA3 and study the relationship between phenotype and CAG repeat number.Methods：Fragment analysis with capillary electrophoresis was applied to count the CAG repeat of MJD gene and was proved with sequencing.Results：Wang＇s family suffered from SCA3.Fragment analysis showed the CAG repeat numbers of three affected cases were 69,75 and 68.Although the sister of proband had no clinical features of MJD,the gene diagnosis revealed that she was affected.Conclusion：Fragment analysis with capillary electrophoresis is the simple and precise method for gene diagnosis of the inherited diseases caused by dynamic mutation.h will provide the convincing evidence for diagnosis and genetic consultation.