应用多重连接依赖性探针扩增技术进行脊髓性肌萎缩症产前诊断

目的 探讨多重连接依赖性探针扩增技术在脊髓性肌萎缩症产前诊断中的临床应用价值.方法 以脊髓性肌萎缩症6个家系作为研究对象.包括患者7例、父母12名、胎儿6例.采用多重连接依赖性探针扩增技术对运动神经元生存(SMN)基囚及脊髓性肌萎缩症修饰基因进行分析,应用聚合酶链反应-限制性酶切片段长度多态性技术检测SMNI基凶缺失,羊水标本分别通过直接离心沉淀和细胞培养进行DNA分析.结果 多重连接依赖性探针扩增分析提示6个家系中7例患者及1例胎儿(家系Ⅳ)呈SMNI基凶纯合缺失,与聚合酶链反应.限制性酶切片段长度多态性分析结果一致;11名父母及5例胎儿的SMNI拷贝数为1,1名母亲(家系V)SMNI拷贝数为2,均为脊髓性肌萎缩症携带者.多重连接依赖性探针扩增分析显示.6个家系中10名成员SMN2拷贝数为1,15名成员SMN2拷贝数为2;多重连接依赖性探针扩增分析.6个家系中3名成员神经元凋亡抑制蛋白(NAIP)基冈缺失,其余家系成员正常.结论 多重连接依赖性探针扩增技术为一快速而可靠的基凶榆测及定量分析方法,可准确检测SMN基凶及脊髓性肌萎缩症修饰基凶的缺失突变并分析基因拷贝数,适用于脊髓性肌萎缩症患者、携带者的基因诊断及产前诊断.

Studies on the prenatal diagnosis of spinal muscular atrophy by multiplex ligation-dependent probe amplification

Objective To investigate the value of multiplex ligation dependent probe amplification(MLPA) method in the prenatal diagnosis of spinal muscular atrophy(SMA).Methods Six SMA pedigrees,which included 7 patients,12 parents and 6 fetuses,were admitted in our hospital.MLPA was used to detect the survival motor neuron(SMN) and other modifier genes,according to steps of hybridization,ligation,PCR reaction,fragment separation by capillary electrophoresis and peak pattern evaluation.Synchronously,the deletion of SMN1 gene was detected by polymerase chain reaction restriction fragment length polymorphism(PCR RFLP).The DNA samples of fetuses were collected by centrifuging the amniotic fluid as well as derived from amniotic cell culture.Results According to MLPA,7 patients and 1 fetus were detected to carry homozygous deletion of survival motor neuron 1(SMN1) gene,which was also detected by PCR PFLP.In addition,11 parents and 5 fetuses carried one copy of SMN1 gene,while 1 parent who was also a carrier of SMA carried two copies of SMN1 gene.Furthermore,after being analyzed by MLPA,10 cases carried one copy of SMN2 gene,while 15 cases had two copies of SMN2 gene.After detecting the neuronal apoptosis inhibitory protein(NAIP) gene,3 cases had the deletion of NAIP gene while others showed normal.Conclusion MLPA can detect the deletion and quantify the copy numbers of SMN and other modifier genes,improving the efficiency and stability of genetic diagnosis.It is adequate for detecting patients and carriers of SMA,as well as providing reliable evidence for genetic counseling.