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Wednesday, December 19, 2012

深圳华大基因…等: 非侵入性產前染色體檢測 (Noninvasive Fetal Trisomy ; NIFTY)


Noninvasive Fetal Trisomy (NIFTY) test: an advanced noninvasive prenatal diagnosis methodology for fetal autosomal and sex chromosomal aneuploidies. BMC Med Genomics. 2012 Dec 1;5(1):57.

BACKGROUND: Conventional prenatal screening tests, such as maternal serum tests and ultrasound scan, have limited resolution and accuracy.

METHODS: We developed an advanced noninvasive prenatal diagnosis method based on massively parallel sequencing. The Noninvasive Fetal Trisomy (NIFTY) test, combines an optimized Student's t-test with a locally weighted polynomial regression and binary hypotheses. We applied the NIFTY test to 903 pregnancies and compared the diagnostic results with those of full karyotyping.

RESULTS: 16 of 16 trisomy 21, 12 of 12 trisomy 18, two of two trisomy 13, three of four 45, X, one of one XYY and two of two XXY abnormalities were correctly identified. But one false positive case of trisomy 18 and one false negative case of 45, X were observed. The test performed with 100% sensitivity and 99.9% specificity for autosomal aneuploidies and 85.7% sensitivity and 99.9% specificity for sex chromosomal aneuploidies. Compared with three previously reported z-score approaches with/without GC-bias removal and with internal control, the NIFTY test was more accurate and robust for the detection of both autosomal and sex chromosomal aneuploidies in fetuses.

CONCLUSION: Our study demonstrates a powerful and reliable methodology for noninvasive prenatal diagnosis.

无创产前基因检测技术具高敏感性和高特异性 发布时间:2012-12-19 来源:药品资讯网信息中心  一项基于大规模平行测序(MPS)的无创产前基因检测技术(简称NIFTY技术)在胎儿染色体非整倍体检测中的临床应用评价结果日前在《临床诊断》(Prenatal Diagnosis)杂志发表。结果显示,NIFTY21-三体综合征及18-三体综合征的检测中具有高特异性和高敏感性。此外,研究人员还提出可以整合基于MPSNIFTY技术,在我国建立新的筛查诊断模型等设想。 胎儿染色体数目异常是一种偶发性疾病,迄今尚无有效的治疗方法,只能通过产前筛查、诊断等手段进行一定程度的预防。但目前传统的产前诊断多采用羊膜穿刺等侵入性取样方法,可能会导致感染并存在一定几率的流产等风险。有研究发现,在孕妇外周血中存在胎儿游离的DNA片段,据此理论,通过取5毫升孕妇静脉血,从中提取源于血浆的游离DNA,采用MPS技术,结合生物信息学分析,从而即可检测出胎儿发生染色体非整倍体疾病,如21-三体综合征又称唐氏综合征、18-三体综合征、13-三体综合征的风险。这种基于MPSNIFTY技术成为一种新的安全检测方法。 本次大规模临床研究由深圳华大基因研究院、深圳华大临床检验中心、首都医科大学、解放军总医院等国内20余家医院合作完成,历时两年之久,纳入高达11105例病例,覆盖范围包括我国15个省和4个直辖市的49个医疗中心。通过对胎儿21-三体综合征和18-三体综合征检测后,共发现190位染色体数目异常的患者,包括14321-三体综合征患者以及4718-三体综合征患者。临床结果显示,NIFTY技术的敏感度达到100%,准确度达到99.96%此外,在本次一万多名参与者中仅有190位(1.17%)染色体数目异常的患者,这说明对于98%的人群来说,侵入性诊断都是可以避免的。基于MPSNIFTY技术所带来的一个伦理学问题就是该方法可对性染色体进行检测,其中包含有胎儿的性别信息。但依据我国当前状况,禁止非医学用途在胎儿出生前公开性别信息。因此,对于胎儿性染色体异常的状况,需要建立综合全面的知情同意程序,使得孕妇能够对是否需要这些附加信息做出最佳决定。

 

 

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