聚合酶链反应技术在腓骨肌萎缩症基因诊断中的应用

PCR in the gene diagnosis of Charcot-Marie-Tooth disease

目的 探讨应用聚合酶链反应 (PCR)技术建立中国人腓骨肌萎缩症 (CMT)基因诊断的方法。方法 分别应用PCR 双酶切、聚合酶链反应 单链构象多态性分析 (PCR SSCP)、聚合酶链反应 变性梯度凝胶电泳 (PCR DGGE)或PCR直接测序等方法对 32个确诊的CMT家系进行了PMP2 2、MPZ、Cx32等致病基因的突变检测。结果 2 1.9%的CMT家系患者有Cx32、MPZ和PMP2 2基因的突变。PCR SSCP检测到 10个家系有异常泳带 ,经PCR测序证实有 5个为多态 ;另 5个为与疾病相关的致病的点突变 ,即 4个Cx32和 1个MPZ基因的点突变。PCR 双酶切诊断了 2个包含PMP2 2基因在内的大片段重复突变的CMT1A型家系。PCR DGGE仅 1个家系患者有异常泳带 ,该结果也可经PCR SSCP方法检出。结论 PCR SSCP和PCR 双酶切可作为Cx32、MPZ、PMP2 2基因的点突变和CMT1A的大片段重复突变的初筛的方法 ,而PCR DGGE方法用于Cx32基因的突变检测不理想 ,点突变应经DNA测序证实。

Objective To establish the gene diagnosis of chavcot-Marie-Tooth disease (CMT) by (PCR) polymerase chain reaction and to study the molecular genetic characteristics of the Chinese CMT. Methods Mutation analysis of the Cx32, MPZ and PMP22 genes were performed by PCR-RFLP, PCR-SSCP , PCR-DGGE and/or direct sequencing in 32 CMT probands of the Hans in China. Results 21.9% of the CMT pedigrees had mutations in the Cx32, MPZ and PMP22 genes . Ten kinds of abnormal bands were found by PCR-SSCP, including 5 kinds of polymorphism and 5 point mutations in the exons of the gene (4 of the Cx32 and 1 of the MPZ). No point mutation of the PMP22 gene was found in these patients but two families (6.3%) were diagnosed as CMT1A by the PCR-RFLP, with the tandem repeat mutation of 1.5 Mb including the PMP22 gene. Conclusion PCR-SSCP and PCR-RFLP are the first two screening methods in the gene diagnosis of CMT. PCR-DGGE is not appropriate for mutation analysis of Cx32. The point mutations must be certificated by sequencing. The mutation screening in the possible X-linkage family has to start with Cx32 gene.