无创DNA阳性结果的验证和分析

The analysis research on abnormal test results of non-invasive prenatal diagnosis

目的探讨无创DNA产前检测在产前诊断中的应用及价值。方法对2012年1月至2014年12月在西京医院妇产科做羊水穿刺的病人资料回顾性分析,发现因无创阳性做羊水穿刺的孕妇84例,用羊水染色体核型分析和FISH对其结果进行验证,并对两者不一致的结果进行电话随访。结果无创DNA84例阳性结果中21-三体48例,经羊水穿刺后确认为假阳性的有2例;18-三体11例,经羊水穿刺后确认为假阳性3例;13-三体4例,经羊水穿刺验证2例为假阳性;性染色体异常21例,经验证6例假阳性。结论孕妇外周血中游离胎儿DNA检测对21-三体检测准确率达95.8%,18-三体准确率73%,性染色体检出准确率71%,13-三体准确率50%。无创DNA是产前筛查21-三体的有效方法,对其他染色体异常的检测还需要进一步提高现有检测技术。

Objective To investigate the clinical application value of non-invasive gene detection of aneuploidy in fetal as noninvasive prenatal diagnosis. Method The amniocentesis and karyotyping results in Xijing Hospital from January 2012 to December 2014 were retrospectively analyzed. The only indication for amniocentesis in these group of woman was positive NIPS （Non-invasive prenatal screening） results. 84 case of positive NIPS results were required for validating by fetal karyotype analyzing through invasive procedures such as amniotic cavity. The NIPT result were compared with the fetal karyotyping and FISH for verification and analysis,telephone follow up after fetus birth for the chromosome result . Results Abnormal 84 cases did amniotic fluid puncture or umbilical cord puncture and chromosome karyotype analysis, 48 cases of trisomy 21 were detected that 2 cases were false positive, 11 cases of trisomy 18 were detected that 4 cases were false positive,4 cases trisomy 13 were detected that 2 cases were false positive, 21cases abnormal in sex chromosome were detected that 6 cases were false positive. Conclusions Sequencing technology of free fetal DNA in pregnant women,detection of trisomy 21 .trisomy 18 .trisomy 13 and abnormal in sex chromosome accuracy up to 95.8 %, 73 %, 71% and 50 %. Non-invasive detection of DNA was an effective method of prenatal screening of trisomy 21, but on trisomy 18.13 trisomy and sex chromosome detection rate,accuracy rate to be further improved existing technologies.