联合应用PCR-SSCP、PCR-限制性酶切和连锁分析法对脊髓性肌萎缩症进行产前基因诊断

Prenatal gene diagnosis of spinal muscular atrophy by combined with the technique of PCR-SSCP, PCR followed by restriction enzyme digestion and linkage analysis

目的 建立脊髓性肌萎缩症 (SMA)的基因诊断方法 ,并且应用于SMA的产前基因诊断。方法 应用聚合酶链反应 (PCR) 单链构像多态性 (SSCP)分析和PCR 限制性酶切分析法对运动神经元存活基因 (SMNT)的第 7外显子进行缺失检测 ;应用紧靠SMN基因的微卫星标记进行单体型连锁分析。结果 家系 1的患者为两个SMNT基因的同源缺失 ,胎儿虽然未发现SMNT基因的同源缺失 ,但是从母亲那儿遗传了一条与患者相同的异常 5号染色体 ,是SMA携带者 ;家系 2的胎儿亦未发现SMNT基因的同源缺失。两家系先证者的母亲各生下了一名正常儿。结论 PCR SSCP分析、PCR 限制性酶切和单体型连锁分析法是诊断SMA的有效方法 ,三者联合使用可以相互验证、互为补充 ,提高产前基因诊断的准确率和成功率。

Objective To investigate and establish the gene diagnosis method for spinal muscular atrophy and apply it to prenatal gene diagnosis.Methods PCR SSCP analysis and PCR restriction enzyme digestion were applied to detect the deletion of the 7 exon of SMNT gene; linkage analysis was applied to detect haplotype by microsatellite marker close to SMN locus. Results Homozygous deletion of SMNT gene has been found in the patient of pedigree 1, whereas homozygous deletion of SMNT gene hasn’t been found in the fetus, which inherited an abnormal chromosome 5 from his mother and the same to the patient Homozygous deletion of SMNT gene also hasn’t been found in the fetus of pedigree 2 Both gave birth to normal babies. Conclusions PCR SSCP analysis, PCR restriction enzyme digestion and linkage analysis are effective methods for SMA diagnosis. We combined these methods as to can verifying and complementing each other, and therefore improving the accuracy of diagnosis