应用多重连接依赖探针扩增技术对脊髓性肌萎缩患者及致病基因携带者进行基因诊断

目的探讨多重连接依赖探针扩增（MLPA）技术对脊髓性肌萎缩（SMA）患者及携带者基因检测的临床应用价值,为进一步创建可靠的SMA产前诊断技术平台奠定基础。方法运用MLPA技术对6例SMA患者及双亲进行运动神经元生存基因（survival of motor neuron gene,SMN）检测,用PCR限制性内切酶片段长度多态性技术（PCR-RFLP）和DNA测序技术对MLPA检测结果进行验证。结果 MLPA试剂盒P021-A1检测6个患者中4个患者为SMN1的外显子7和外显子8缺失纯合子,2个患者为SMN1外显子7缺失纯合子;6例患者的12名双亲的SMN信号值均明显比正常对照组低30%～50%。同时还检测出部分患者及携带者GTF2H2（BTF2p44）和BIRC1（NAIP）基因存在病变。P060-A2检测出12名携带者SMN1信号比正常对照组降低30%～50%,其中3名合并BIRC1基因信号降低。PCR-RFLP和DNA测序技术支持MLPA有关SMN基因检测结果。结论 MLPA技术能对SMA患者及携带者进行快速可靠的基因诊断。通过MLPA技术分析SMN邻近基因的基因突变和（或）缺失情况,为SMA患者基因型和临床分型诊断提供依据。

Gene diagnosis and carriers detection of spinal muscular atrophy by multiplex ligation-dependent probe amplification

Objective To study the value of MLPA （multiplex ligation-dependent probe amplification） technique in the gene diagnosis and create a reliable platform of prenatal diagnosis for spinal muscular atrophy（SMA）.Methods Genomic DNA samples from patients were analyzed by applying SALSA MLPA kit P021-A1.DNA from parents of 6 patients were analyzed by SALSA MLPA kit P060-A2.PCRRFLP and DNA sequencing techniques were used to confirm SMN gene deletion.Results MLPA analysis by kit P021-A1 showed that all 4 patients with SMA presented homozygous deletion of exon 7 and exon 8 of SMN1 gene while the another 2 patients were homozygous deletion of exon 8 of SMN1 gene.Moreover,mutations and/or small deletion in genes like GTF2H2 and BRIC1 adjacent to gene SMN were detected in parts of patients and their parents by MLPA.Conclusions MLPA is a rapid and reliable diagnostic method for patients and carriers of spinal muscular atrophy.Relationship between genotype and phenotype would be analyzed by detecting mutaion and/or deletion in genes such as GTF2H2 and BRIC1.