五个脊肌萎缩症高风险胎儿的产前诊断  

Prenatal diagnosis of 5 fetuses with high risk of developing spinal muscular atrophy

作　　者：兰风华[1] 曾健[1] 黄惠娟[2] 柯龙凤[1] 涂向东[1] 黄梁浒[1] 李惠忠[3] 郑德柱[1] 杨渤生[4] 

机构地区：[1]南京军区福州总医院遗传病分子诊断中心,福州350025 [2]南京军区福州总医院遗传病分子诊断中心妇产科,福州350025 [3]南京军区福州总医院遗传病分子诊断中心超声科,福州350025 [4]南京军区福州总医院遗传病分子诊断中心神经内科,福州350025

出　　处：《中华医学遗传学杂志》2007年第4期373-377,共5页Chinese Journal of Medical Genetics

摘　　要：目的对5名生育过脊肌萎缩症（spinal muscular atrophy，SMA）患儿的妇女当前所怀胎儿进行产前诊断。方法超声监视下行羊膜腔穿刺术抽取羊水。离心后直接从沉渣中提取胎儿基因组DNA。采用短串联重复序列位点检测法排除母体基因组DNA污染。常规PCR扩增胎儿SMN基因第7外显子。PCR产物经DraI酶切后，行琼脂糖凝胶电泳。通过位点特异性PCR扩增SMTVI和SMTV2的第7外显子。结果比较各胎儿与父母的16个短串联重复序列位点，未见羊水DNA受母体DNA污染迹象。常规PCR中，胎儿A、C、D的PCR产物（189bp）仅有部分可被DraI切割，而胎儿B、E的PCR产物全部被Dra I切割。在位点特异性PCR中，胎儿A、C、D既有SMTVI、也有SMTV2的第7外显子扩增产物，而胎儿B、E只有SMTV2的第7外显子扩增。结论胎儿A、c、D未见SMTVI纯合性缺失，出生后患SMA的风险极小；胎儿B、E为SMTVI纯合性缺失，出生后患SMA的风险极大。Objective To perform prenatal diagnosis for 5 pregnant women who had given birth to children with spinal muscular atrophy （SMA）. Methods Thirty to forty mililiters of amniotic fluid was obtained by amniocentesis under ultrasonic monitoring. DNA was extracted directly from sediment of amniotic fluid. Short tandem repeat （STR） profiling was carried out to evaluate the contamination of amniotic DNA by matemal genomic DNA. Two methods, PCR-re- striction fragment length pelymorphism （PCR-RFLP） and allele-specific PCR, were used to analyze exon 7 of SMN gene from amniotic DNA. Results Comparing the 16 STR sites of each fetus with those of his/ber parents, there was no or little contamination of amniotic DNA by matemal genomic DNA. In conventional PCR-RFLP, part of the PCR product （189 bp） from amniotic DNA of fetus A, C, or D remained intact after digestion with Dra I , while the PCR product from amniotic DNA of fetus B or E was completely digested by Dra I . In allele-specific PCR, exon 7 of both SMNI and SMN2 gene could be seen when amniotic DNA of fetuses A, C, or D was analyzed, while only exon 7 of SMTV2 could be seen when amniotic DNA of fetuses B or E was analyzed. Conclusion Homozygous deletion of SMNI is not detected in fetuses A, C, and D, predicting that the risk of developing SMA after birth would be extremely low. Homezygous deletion of SMNI was present in fetuses B and E suggesting high risk of developing SMA after birth.

关 键 词：脊肌萎缩症 产前诊断 分子诊断 

分 类 号：R686[医药卫生—骨科学]