中文摘要：

目的：通过对脊柱裂（spina bifida）胚胎脑组织中微卫星不稳定性（microsatellite instability,MSI）的分析,探讨遗传不稳定性是否为此疾病的特征之一,进而研究错配修复系统（mismatch repair,MMR）与脊柱裂发病的分子机制。方法：19例脊柱裂和19例非神经管畸形对照脑组织中提取DNA;尿素变性凝胶电泳法检测标本中MSI发生情况。结果：在19例脊柱裂脑组织中9例MSI阳性,阳性率47.4%。其中2例为高度微卫星不稳定（high frequency microsatellite instability,MSI-H）,7例为低度微卫星不稳定（lowfrequency microsatellite instability,MSI-L）,其余10例为微卫星稳定（microsatellite stable,MSS）,对照组中未出现MSI。选择的5个微卫星位点MSI的阳性率分别为Bat34C4（10.5%）、Bat26（26.5%）、D2S123（10.5%）、D3S1611（5.3%）,D2S119（5.3%）。结论：脊柱裂中存在MSI现象,提示MSI、错配修复系统可能与脊柱裂的发生有一定关系。

英文摘要：

Objective： To investigate microsatellite instability（MSI） in fetuses with spina bifida and explore whether genetic insta-bility is a feature of this disease,and to study the molecular mechanism between mismatch repair（MMR） and the occurrence of spina bifi-da.Methods： DNA was extracted from 19 cases of spina bifida and the control group.PCR-urea denaturing polyacrylamide gel elec-trophoresis was used to analyze MSI.Results： Of 19 cases of spina bifida,9 with MSI（47.4%）,2 with MSI-H,7 with MSI-L and 10 with MSS.Positive cases of five microsatellite loci were 2 for Bat34C4（10.5%）,5 for Bat26（26.5%）,2 for D2S123（10.5%）,1 for D3S1611（5.3%） and 1 for D2S119（5.3%） respectively.No MSI was found in normal group.Conclusion： The high incidence of MSI was found in fetuses with spina bifida,which indicated that MSI and MMR may be correlated with the occurrence of spina bifida.