无创产前筛查在胎儿性染色体异常诊断中的应用价值

Clinical application of non-invasive prenatal testing to detect the fetal sex chromosome abnormality

目的探讨无创产前筛查(non-invasive prenatal testing,NIPT)在胎儿性染色体异常诊断中的临床应用价值。方法比较NIPT组(NIPT联合传统筛查)和对照组(传统筛查)之间胎儿性染色体异常检出率,进一步分析2组真阳性孕妇筛查的高风险因素。结合羊水核型验证评价NIPT 5类性染色体异常高危提示的准确率。结果 NIPT组和对照组胎儿性染色体异常的检出率分别为0. 227‰、0. 081‰。在NIPT组中,年龄高风险和T21高/中风险人群的胎儿性染色体异常检出率均高于对照组。本实验中NIPT筛查XYY和XXY高风险提示的准确率达100%,而XO和XXX高风险提示的准确率却仅为45%、50%。此外,NIPT筛查还检测到性染色体不平衡结构异常3例,性染色体嵌合2例。结论全基因低深度测序的NIPT筛查特异性覆盖了性染色体,开展NIPT筛查能提高胎儿性染色体异常的检出率。

Objective To explore the clinical value of non-invasive prenatal testing( NIPT) in screening the fetal sex chromosome aneuploidies( SCAs). Methods The SCAs rate was compared between the NIPT group( prenatal traditional screening combined with NIPT) and the control group( traditional prenatal screening). Then the high-risk factors were analyzed in the true positive cases. Combining with the result of karyotype,it proceeded to evaluate the accuracy of five SCAs hints in NIPT screening. Results The detectable rate of SCAs in NIPT group and control group was respectively 0. 227‰,0. 081‰. It was higher in the NIPT group than the control group especially for the pregnant women with age high-risk or T21 high/medium risk. The accuracy of XYY and XXY hint from NIPT screening was almost 100%,while the accuracy of XO and XXX hint were only 45% and 50% in the study. Finally 3 unbalanced structural abnormal cases and 2 mosaic cases were also found in sex chromosomes. Conclusion NIPT that is focused on the whole-genome sequencing with low depth definitely covers the sex chromosomes,and NIPT screening can improve the detection rate of fetal sex chromosome abnormalities.