孕妇外周血游离DNA深度测序在胎儿染色体非整倍体无创检测中的应用研究

Detection of fetal chromosomal aneuploidies by deep sequencing of cell-free DNA in maternal peripheral blood

目的:评估孕妇外周血胎儿游离DNA高通量测序在检测胎儿染色体非整倍体异常中的优势。方法:通过高通量测序技术检测1 000例妊娠13周以上孕妇的外周血中胎儿游离DNA,判断胎儿非整倍体异常,通过传统染色体核型分析及胎儿出生后的临床随访对检测结果进行验证。结果:1 000例标本中1例检测失败,其余999例中共检出18例异常,其中12例21三体,2例18三体,1例13三体,1例X单体,1例X三体,1例XXY。12例21三体阳性病例中,有1例为双胎妊娠,核型分析显示一胎正常,一胎为21三体;1例X三体经核型分析诊断为正常女性,其余检测结果均与染色体核型分析结果相符,对于21三体、18三体、13三体和性染色体非整倍体异常的总阳性检测率94.44%。所有检测结果为阴性者,均进行产后随访新生儿面容、体格发育等情况,未发现有21三体、18三体、13三体等常见染色体非整倍体异常征象,无假阴性病例。结论:孕妇外周血胎儿游离DNA高通量测序对于检测胎儿21三体、18三体和13三体准确度高,对性染色体非整倍体的检测,本技术检测指标有待进一步提高。

Objective：To explore advantages of high-throughput sequencing of cell-free DNA from maternal peripheral blood for detection of chromosomal aneuploidies in prenatal diagnosis. Methods：A total of 1 000 maternal peripheral blood samples from gravidas with more than 13 weeks of pregnancy were collected, and the cell-free DNA in the peripheral blood samples were detected using high-throughput sequencing to determine chromosomal aneuploidy. The cases of chromosomal aneuploidies and euploidies were validated by traditional chromosomal karyotype analysis and clinical follow-up of babies after the birth. Results：In the analyses of 1 00（3 cases, one case failed. The results of the remaining 999 cases indicated 18 cases of abnormalities,including 12 cases of trisomy 21 ,two cases of trisomy 18,one case of trisomy 13,one case of X monomers,one case of trisomy X,one case of XXY. From 12 cases of trisomy 21 ,there was one case of gemellary pregnancy,and the results of fetal karyotype analysis showed that one fetal was euploid and the other fetal was trisomy 21. One case of trisomy X was validated as euploid by karyotype analysis and the remaining detection results were consistent to those with karyotype analysis. The total positive detection rate of trisomy 21,trisomy 18,trisomy 13 and sex chromosome aneuploidy was 94.44%. No abnormal signs of chromosome aneuploidies （trisomy 21 ,trisomy 18 and trisomy 13） were found in follow-up of face and physical development of babies after the birth for all cases with negative results, and there were no false-negative cases. Conclusion：High-throughput sequencing of cell-free DNA from maternal peripheral blood has high accuracy for detecting fetal trisomy 21, trisomy 18 and trisomy 13. For sex chromosome aneuploidy detection,measurement indicators in this study should be further improved.