PCR-RFLP法在脊髓性肌萎缩症基因检测中的局限性  

Limitation of PCR-RFLP method for the detection of genetic mutations in spinal muscular atrophy

作　　者：金煜炜[1] 瞿宇晋[1] 王红[1] 白晋丽[1] 宋昉[1] 

机构地区：[1]首都儿科研究所医学遗传学研究室,北京100020

出　　处：《中华医学遗传学杂志》2012年第1期34-37,共4页Chinese Journal of Medical Genetics

基　　金：国家自然科学基金（81050034）;北京市自然科学基金（7112020）

摘　　要：目的探讨聚合酶链反应一限制性片段长度多态性（polymerase chain reaction-restriction fragment length polymorphism，PCR-RFLP）技术在脊髓性肌萎缩症（spinal muscular atrophy，SMA）基因诊断中的应用。方法用PCR-RFLP分析935例临床疑似SMA患儿的运动神经元存活基因1（survivalmotor neuron，SMNl）第7和第8外显子的缺失，同时用多重连接探针扩增技术（multiplexligation-dependent probe amplification，MLPA）分析其中339例疑似病例的SMNl基因拷贝数改变。用Pearson卡方检验分析两种方法检测SMNl纯合和杂合性缺失的一致性。结果共发现SMNl基因第7外显子纯合缺失590例，疑似患者的SMA基因诊断率为63．1％（590／935）。用PCR_RFLP和MLPA技术联合分析疑似病例339例，PCR-RFLP共发现SMNl纯合缺失194例，MLPA发现196例，二者的一致性为98．9％，差异无统计学意义（X2=0．2，P=0．88）。PCR-RFLP仅发现SMNl疑似杂合性缺失4例，而MLPA证实有17例，二者的一致性为23．5％，差异有统计学意义（X2=8．29，P〈0．01）。结论PCR-RFLP尽管简便、特异、实用，但对于5％-10％SMNl杂合缺失合并点突变的病例则存在明显的局限性。Objective To explore the applicability and limitation of PCR-restriction fragment length polymorphism （PCR-RFLP） method for genetic diagnosis of spinal muscular atrophy （SMA）. Methods PCR-RFLP was applied to detect potential deletion in exons 7 and 8 of SMN1 gene in 935 suspected cases with SMA. Multiplex ligation-dependent probe amplification（MLPA） was carried out to analyze dosage alteration of SMN1 gene in 339 of such cases. To confirm the accuracy of PCR-RFLP method for homozygous and heterozygous deletions detection, the consistency of PCR-RFLP and MLPA results were assessed with a Pearson Chi-square test. Results Homozygous deletion of exon 7 of SMN1 was detected in 590 suspected cases. The rate of diagnosis was therefore 63.1% （590/935）. For the 339 suspected cases, PCR-RFLP and MLPA respectively identified 194 and 196 homozygous deletions in the exon 7 of SMN1 gene, suggesting a good consistency （98.9 %） （X2 = 0.2, P = 0.88）. However, only 4 of 339 cases was found to carry a heterozygous deletion of SMN1 exon 7 by PCR-RFLP, in contrast with 17 detected by MLPA. The consistency only reached 23.5%, for which statistical significance was detected （2= 8.29, P〈0.01）. Conclusion Although PCR-RFLP is a simple, specific and efficient method for SMA diagnosis, it has obvious limitation for the diagnosis of 5%-10% SMA patients who have carried a compound heterozygous mutation.

关 键 词：脊髓性肌萎缩症 运动神经元存活基因1 限制性片段长度多态性 多重连接探针扩增技术 

分 类 号：R746[医药卫生—神经病学与精神病学]