目的 评估国内现有的有创性产前诊断技术中母体细胞污染(MCC)的发生率及其对产前诊断结果的影响.方法 采用单中心大样本量研究方案,在2011年10月至2012年1月期间采用PowerPlex 16系统对519例孕中期羊水标本、57例孕早期绒毛标本及对应的576例孕妇外周血标本进行短串联重复序列(STR)分型,根据分型结果判断是否存在MCC及MCC的程度；结合核型分析结果和分子遗传学诊断结果分析MCC对产前诊断的影响.结果 3.1％(16/519)未经培养的羊水标本和1.3％(7/519)培养后的羊水标本存在MCC;5％(3/57)未经培养的绒毛标本存在MCC.MCC对于正常核型女性胎儿的核型分析无影响,但是增加了男性胎儿被误判为两性嵌合体,或者异常核型胎儿被误判为异常/正常核型嵌合体的风险.MCC对不同分子遗传学诊断方法的影响不同,对于基于PCR的基因定性分析,10％ MCC即可造成错误的分析结果；对于定量分析,10％及以上的MCC即对分子遗传学诊断结果产生干扰,30％ MCC可导致错误的诊断结果.结论 MCC可能影响产前诊断结果,核型为嵌合体的产前诊断羊水标本和可疑MCC的绒毛标本均应当进行MCC排除实验；MCC对于分子遗传学诊断结果的影响更为明显,建议产前分子遗传学诊断应尽可能常规进行胎儿组织标本的MCC排除实验.%Objective To assess the frequency and significance of maternal cell contamination (MCC)in the invasive prenatal diagnosis,and to analysis the MCC effect on prenatal diagnosis results.Methods Totally 519 amniotic fluid samples from second trimester pregnancy,57 chorionic villus samples from first trimester pregnancy,and 576 blood samples from corresponded pregnant women were collected and genotyped by Promega PowerPlex 16 system.MCC was determined according to the genotyping results.Karyotypic and molecular diagnosis results were contrasted between MCC and non-MCC specimen of the same fetal.Results MCC presented in 3.1％(16/519)uncultured amniotic fluid,1.3％(7/519)cultured amniotic fluid and 5％(3/57)villi specimens.In the study of fetal karyotype,MCC had no significant effect on normal female fetus;but for male fetus and abnormal female fetus,there were risk of erroneous results of mosaics.As to molecular diagnosis,MCC resulted in more complex effects for the different diagnostic methods.And 10％ MCC had led to misdiagnosis.Conclusions For the prenatal cytogenetic tests,MCC should be excluded when there were mosaicism karyotype results or suspicious MCC of chorionic villi samples.The effects of MCC had more seriously impact on prenatal molecular testing,which suggesting the recommend regular identity test for MCC should bc carried out.
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