孕妇外周血游离胎儿DNA诊断胎儿染色体异常的研究进展

胎儿染色体异常是我国当前控制和预防出生缺陷的重点目标疾病。近年来开展的孕妇外周血游离胎儿DNA(cell-free fetal DNA,cff DNA)检测这一新技术对诊断胎儿染色体异常具有很高的敏感性和特异性,是对原有产前筛查和产前诊断技术的有效补充。本文就孕妇外周血游离胎儿DNA诊断胎儿染色体异常的研究进展进行综述。     

孕妇血浆游离DNA在唐氏综合征筛查中的应用

目的探讨孕妇血浆游离DNA定量检测在唐氏综合征筛查中的价值。方法采用实时定量荧光PCR检测孕中期孕妇,唐氏综合征高危孕妇的血浆中3-磷酸甘油醛脱氢酶基因(GAPDH)及男性特有Y性别决定区(sex determ in ingregion Y,S R Y)基因。结果孕中期、唐氏综合征高危孕妇GAPDH拷贝数均值分别为(4.28±1.36)×103copy/m l,(3.08±1.67)×104copy/m l;孕中期、唐氏综合征高危孕妇的SRY拷贝数均值分别为174.02±98.56 copy/m l、1065.01±588.72 copy/m l。孕中期和唐氏高危孕妇血浆游离DNA含量有显著性差异。结论孕妇血浆游离DNA的定量分析在唐氏综合征筛查中有重要的价值。     

应用QF-PCR技术研究孕妇血浆中胎儿游离DNA与染色体非整倍体妊娠的关系

目的孕21三体胎儿孕妇血浆中胎儿游离DNA水平明显高于正常孕妇,该研究旨在评价妊娠时期孕妇血浆中胎儿游离DNA作为筛查唐氏综合征指标的意义及可行性。方法应用荧光定量PCR技术(QF-PCR)检测怀孕唐氏综合征男胎孕妇和孕正常男胎孕妇血清中胎儿游离DNA的水平。15例孕唐氏综合征男胎孕妇和25例孕正常男胎孕妇及10例孕正常女胎孕妇参与该项研究。结果孕唐氏综合征孕妇血清中胎儿游离DNA水平为185.8基因当量/ml,明显高于正常组(81.9基因当量/ml),P=0.005。结论孕唐氏综合征男胎孕妇血清中胎儿游离DNA含量明显高于正常组,提示荧光定量PCR技术检测孕期母血中胎儿游离DNA水平可能成为筛查唐氏综合征的一个有效指标。     

孕妇血浆中的游离胎儿DNA及其意义

孕妇血浆中已证实存在着胎儿来源的游离DNA。作为一种胎儿新的检测材料,游离胎儿DNA的发现为非侵入性产前基因诊断提供了可能。有关游离胎儿DNA的临床应用以及其生物学包括来源、动力学和性质等,近年来引起人们很大关注。实时定量PCR技术是目前检测孕妇血浆中游离胎儿DNA的主要方法。实验室的一些技术因素会影响游离胎儿DNA的检测。尽管有些问题还不很清楚,但母体血浆中游离胎儿DNA的检测对于胎儿遗传病和妊娠相关性疾病的非侵入性产前诊断仍具有重要临床意义。讨论孕妇血浆中游离胎儿DNA的最新研究状况。     

孕妇血中胎儿微小RNA等核酸在唐氏综合征无创产前诊断中的应用

唐氏综合征是最常见的染色体非整倍体遗传病,出生干预是预防该病的有效措施.传统的产前诊断具有创伤等缺陷,无创产前诊断是未来发展的需求.孕妇血胎儿细胞、胎儿游离DNA、胎儿游离RNA及胎儿游离microRNA的分析是新近发展的4种唐氏综合征无创产前诊断技术.母血胎儿游离miRNA有足够的稳定性、特异性和准确性,是最具临床应...     

孕妇血浆中游离胎儿DNA的检测与分析

目的 建立不依赖于胎儿性别和父本DNA、可适用于染色体数目异常和单基因遗传病的无创性产前诊断方法.方法 应用降落PCR和二次PCR扩增技术,联合检测41例正常孕妇(其中孕龄7 w 1例,14～20 w 39例,32 w 1例)血浆中游离胎儿DNA的SRY基因和D17S1293、D21S11、DXS8377等3个短串联重复序列(short tandem repeat,STR)位点.SRY基因扩增产物进行琼脂糖凝胶电泳,STR位点扩增产物进行变性聚丙烯酰胺凝胶电泳并银染显色.结果 41例孕妇血浆DNA中均检出非母源性等位基因条带;联合SRY基因和X-STR位点鉴定胎儿性别,38例判断明确,3例不能明确判断性别.结论 检测孕妇血浆中的游离胎儿DNA,可快捷地获得男性胎儿和女性胎儿的父源性DNA信息,不仅适用于性连锁遗传疾病,而且适用于常染色体遗传疾病等的产前基因诊断.     

孕妇血浆及血清中胎儿游离DNA及RNA的研究进展

当今,无创伤性产前诊断越来越受到人们的关注,许多学者利用孕妇血中胎儿细胞进行产前遗传疾病的研究,但由于孕妇外周血中的胎儿细胞数量稀少,必须通过复杂的富集分离技术,但价格昂贵,因此限制了其临床推广应用。近来孕妇血浆及血清中的胎儿游离DNA及RNA的发现为无创伤性产前遗传病诊断开辟了一个新的天地。由于胎儿游离DNA及RNA具有含量较高且产后很快被清除等优点,使之成为未来最具潜力的无创伤产前诊断方法。     

孕妇血浆胎儿游离DNA检测对胎儿染色体拷贝数异常的诊断意义

目的 探讨应用孕妇血浆胎儿游离DNA高通量基因测序技术检测胎儿染色体拷贝数的准确性和实际临床可行性.方法 选择需做产前诊断的153名孕妇,采用高通量基因测序技术检测母体血浆胎儿游离DNA,分析胎儿染色体拷贝数;同时行羊膜腔穿刺进行胎儿染色体核型分析.结果 153名孕妇中,母体血浆游离DNA平行测序技术共检测出6例染色体异常高风险胎儿.羊水分析证实6例均为染色体异常,其中非整倍体5例,分别为47,XYY; 45,X;47,XY,+18;47,XY,+21以及47,XY,+13;染色体结构异常1例,核型为46,XY,der (13; 21)(q10; q10),+21.另检出染色体多态性3例(1例46,XY,21p+;2例46,XY,Yqh-).两种方法检测胎儿染色体拷贝数异常结果一致.结论 母体血浆游离DNA高通量测序分析可以用于胎儿染色体拷贝数异常的检测,具有无创、灵敏度高、特异性强等优点,在胎儿染色体拷贝数异常疾病的产前检测中具有广泛的应用前景.     

唐氏综合征的无创产前诊断研究进展

唐氏综合征是最常见的染色体非整倍体遗传病,该病尚无有效治疗手段,出生干预是预防该病的有效措施。传统的产前筛查与产前诊断均具有一定的缺陷,无创产前诊断是未来发展的趋势。本文从母血胎儿细胞、母血胎儿游离DNA、母血胎儿游离RNA三个角度对目前唐氏综合征的无创产前诊断研究作一综述,以期对相关领域的研究发展有所帮助。     

利用孕妇外周血中的胎儿物质产前诊断唐氏综合征

唐氏综合征又称先天愚型 ,是先天性智力低下的最常见的遗传因素。早在 186 6年英国医生LangdonDown首次对此病例作过临床描述 ,故称Down综合征。据资料统计 ,目前 ,唐氏征新生儿的发病率为 1‰～ 2‰[1] ,给社会和家庭带来了极大的防治责任。由于缺乏有效的治疗措施 ,预防及控制患儿的出生是医学界的重大研究课题之一。近几十年来 ,借助先进的细胞遗传学和分子生物学检测技术 ,我们的产前筛查工作取得了一定的进展。目前 ,先天愚型的产前筛查工作主要是通过检测孕妇血液生化指标如AFP、hCG、uE3,羊水细胞及脐血细胞的染色体核型分析及超…     

妊娠期高血压疾病孕妇外周血中游离胎儿DNA的检测

目的探讨实时荧光定量PCR（RQ—PCR）检测孕妇外周血中胎儿游离DNA对预测及预防妊娠期高血压疾病的应用价值。方法选15例子痫前期孕妇及正常孕妇20例，用RQ—PCR法检测各例血浆中GAPDH及SRY水平，通过2^-△△ct法分析两组孕妇间的差异。结果22例孕男胎检出SRY21例，13例孕女胎均未检出，子痫前期组胎儿DNA水平明显高于正常组（P=0．009），两者比值为3．57。结论RQ—PCR法检测孕妇外周血中胎儿DNA可作为预测及预防妊高征的一种有效手段。     

不同妊娠状态下孕妇外周血中游离胎儿DNA定量分析

目的对不同妊娠状态下孕妇外周血中游离胎儿DNA(f DNA)定量分析,确定其平均浓度及临床参考值范围,初步探讨在不同妊娠状态下母血中f DNA的浓度变化,为临床应用提供科学依据。方法从孕妇外周血浆中提取fDNA,用实时荧光定量聚合酶链反应(FQ-PCR)方法检测其中Y性别决定区的SRY基因。结果在正常早期的孕妇组38例血浆标本中有32例检测到SRY基因,其平均浓度149.25拷贝数/ml,参考值范围为33.28~265.22拷贝数/ml;在正常晚期的孕妇组32例血浆标本中全部检测到SRY基因,其平均浓度为212.14拷贝数/ml,参考值范围为142.76~281.52拷贝数/ml;在晚期患有子痫前期的孕妇30例血浆标本中全部检测到SRY基因,其平均浓度为678.70拷贝数/ml,参考值范围为595.01~726.40拷贝数/ml。实验数据用单因素方差分析,组间差异显著性检验用LSD-t检验。妊娠晚期孕妇血浆中f DNA的含量较妊娠早期升高,约为1.4倍,有统计学意义(P<0.01);晚期患子痫前期的孕妇血浆f DNA的水平是同期正常对照组的3.9倍,有统计学意义(P<0.01)。结论1.用FQ-PCR法最早在孕48天孕妇外周血中即可检测到fDNA。2.随着妊娠的进展孕妇血浆中f DNA的含量升高。3.晚期患子痫前期孕妇其血浆f DNA的水平是同期正常对照组的3.9倍,有统计学意义(P<0.01)。4.f DNA在进行无创伤性产前诊断中有重要价值。     

Basal FSH, estradiol and inhibin B concentrations in women with a previous Down's syndrome affected pregnancy.

BACKGROUND: Two recent studies reported elevated basal FSH concentrations in women with a history of aneuploid conceptions. However, it is not known whether these elevated basal FSH concentrations reflect depletion of the primordial follicle pool, or were caused by an increased secretory drive for FSH. METHODS: Inhibin B and estradiol concentrations were measured as indicators for depletion of the primordial follicle pool in women with a history of a Down's syndrome pregnancy and in controls. RESULTS: In the women with a history of a Down's syndrome pregnancy, there was a significant inverse correlation between basal FSH and inhibin B concentrations (P < 0.0001, 95% CI -0.26 to -0.56). In the control group, this correlation did not reach statistical significance. CONCLUSIONS: Our data indicate that the elevated basal FSH concentrations observed in women with a history of a Down's syndrome pregnancy are likely to reflect early depletion of the primordial follicle pool. Therefore, further research into the ovarian ageing process could provide more insight in the origination of chromosomal abnormalities during pregnancy.     

Correlation of maternal plasma total cell-free DNA and fetal DNA levels with short term outcome of first-trimester vaginal bleeding

BACKGROUND: The current methods using sonographic parameters and/or maternal serum beta-HCG levels to predict spontaneous abortion are not satisfactory. The aim of this study was to determine whether maternal plasma fetal DNA and total DNA levels could be used to predict spontaneous abortion. METHODS: We prospectively studied pregnant women who presented with vaginal bleeding in the first trimester of pregnancy, and those who had no vaginal bleeding (controls). DYS14 and the beta-globin gene were used to measure the maternal plasma levels of fetal and total DNA, respectively, by real-time PCR. RESULTS: A total of 1114 women were studied. Both maternal plasma fetal and total DNA concentrations increased with gestation from 6 to 11.6 weeks in the controls. The multiple of medians (MoMs) of fetal and total DNA concentration in those who miscarried were significantly greater (P < 0.001) than in the normal controls by about 5- and 4-fold respectively. Using a cut-off value of 1.6 MoMs for total DNA to predict spontaneous abortion, the sensitivity was 98.2% and false positive rate was 4.7%. However, using a cut-off value of 1.8 MoMs for fetal DNA, the corresponding figures were 97% and 44.3%, respectively. CONCLUSIONS: Both maternal plasma fetal and total DNA concentrations increased throughout the first trimester. Significantly high levels of fetal and total DNA were found in those who miscarried.     

唐氏综合征孕中期多指标联合筛查方案适用性评估

目的 对孕中期多种产前筛查方案进行比较、评价,为选择较为适宜的方案提供依据.方法 收集2009年在青岛市产前诊断中心知情同意接受产前筛查的单活胎妊娠30 547例,分别检测母血清中二联或三联血清标记物,均用Lifecycle软件评估胎儿罹患唐氏综合征的风险,对二者的检出率和成本效益进行比较、分析;同时收集64例唐氏综合征妊娠的血清标本,采用二联筛查(double test,DT)+2T-Risks软件计算风险(DT-2T),二联筛查+Lifecycle软件计算风险(DT-LC),三联筛查(triple test,TT)+2T-Risks软件计算风险(TT-2T)和三联筛查+ Lifecycle软件计算风险(TT-LC)4种不同的筛查方案对胎儿罹患唐氏综合征的风险进行评估,并对各种不同的筛查方案进行比较、评价.结果 (1)64例唐氏综合征妊娠的血清标本,采用Lifecycle软件进行风险评估,检出率均高于同样指标筛查而采用2T-Risks软件评估风险方案;三联筛查不适宜使用2T-Risks软件;(2)30 547例单活胎妊娠的筛查中,DT-LC方案和TT-LC方案对于唐氏综合征的检出率分别为56.25%和57.14%;每检出1例唐氏综合征的平均费用DT-LC方案明显低于TT-LC方案,为优选方案.结论 孕中期DT-LC方案是一种利于在全国广泛开展的、经济有效的筛查方案.

Abstract：

Objective To provide basis for selecting the suitable method of Down's syndrome biochemical screening in the second trimester pregnancy. Methods A total of 30 547 singleton pregnancies between 14 and 20+6 weeks of pregnancy were collected and analyzed for maternal serum alpha-fetoproteins (AFP) and human chorionic gonadotrophin,free beta subunit (β-HCG) with or without unconjugated estriol (uE3). The screening risks were calculated using the software Lifecycle. The detection rates and the cost of per Down's syndrome detected were calculated and compared. And four different methods were compared in a series of 64 serum samples from Down's syndrome pregnancies. Results (1) Among the 64 affected cases, the detection rate of Down's syndrome was improved no matter in the double test (DT) or in the triple test (TT) if software Lifecycle (LC) was used to evaluate risks. And it was not suitable to evaluate risks with software 2T-Risks in the triple tests. (2) In the cohort of 30 547 singleton pregnancies, the detection rate of Down's syndrome with project DT-LC, which was double test using AFP and free β-HCG together with software Lifecycle, and project TT-LC, which was triple test using AFP, free β-HCG and uE3 together with software Lifecycle, was 56.25% and 57.14%, respectively. The former project was better because it decreased the false positive rate at a lower running cost. Conclusion The DT-LC is an effective screening strategy for second trimester detection of fetal Down's syndrome in mainland China.     

孕妇血浆中胎儿游离DNA的生化特征及其应用研究新进展

孕妇血浆中胎儿游离DNA,源于胎儿细胞和(或)胎盘的凋亡,经核酸内切酶选择性地剪切为313bp以下的短片段分子,在孕早期和孕晚期分别平均占血浆DNA总量的3.4%和6.2%,因相对含量丰富,已成为当前无创伤性产前分子遗传诊断中胎儿DNA的重要来源,现开展了胎儿性别鉴定、RhD阴性孕妇的Rh(D)基因检测、胎儿非整倍体病的诊断、STR遗传标记检测等应用研究。该文对母体血浆中胎儿游离DNA的来源、胎儿游离DNA的浓度、纯度、分子片段大小和分布、产后清除等基础性研究以及业已开展的临床应用,进行了总结和分析。根据胎儿游离DNA的生化特征和检测的靶基因,采用相应的分子基因诊断策略和实验设计,限制扩增产物的片段长度和优化PCR反应条件,有助于提高无创伤性产前胎儿分子遗传诊断的成功率。     

手术终止妊娠对早孕妇女外周血中游离胎儿DNA的影响

目的检测在孕早期手术终止妊娠是否会对母体外周血浆中的胎儿DNA水平造成影响。方法选择孕6~9w妇女36例(自愿要求终止妊娠,无禁忌症,胎儿性别为男性),在其终止妊娠前后分别采取外周静脉血5m l,对其血浆中的游离胎儿DNA的SRY基因行荧光定量分析。结果在36例血浆标本中,术前有31例检测到胎儿DNA,术后全部检测到胎儿DNA。其浓度平均分别为62.40±21.70(31.80~128.00Eq/m l),101.04±37.40(58.20~209.70Eq/m l),术前与术后胎儿DNA含量有统计学差异(P<0.01)。结论①孕妇外周血中游离胎儿DNA最早在孕45天即可检测到。②外周血中游离胎儿DNA的水平在妊娠终止后很快升高。③孕妇外周血中的游离胎儿DNA很可能来源于母胎之间出血。     

孕妇血浆中胎儿DNA在产前诊断中的应用

目的 探讨孕妇血浆中胎儿DNA在无创性产前诊断中的应用。方法 应用酚—氯仿法抽提44名孕7～41周妇女血浆中胎儿DNA，通过PCR扩增胎儿Y染色体上DYZl位点，长度为149bp。结果 22名妊娠男性胎儿孕妇中全部出现DYZ1基因扩增条带，检出率为100．00％。22名妊娠女性胎儿孕妇中20例为阴性结果，两例假阳性结果。早、中、晚孕期性别符合率分别为88．89％、100．00％、96．55％，总符合率为95．45％。结论 使用酚—氯仿法抽提血浆中的DNA。提高模版的浓度和纯度进行PCR，增加了结果的准确性。提示母体血浆中游离的胎儿DNA可以作为无创性产前诊断的标本来源。     

Systematic evidence-based review: The application of noninvasive prenatal screening using cell-free DNA in general-risk pregnancies

PurposeNoninvasive prenatal screening (NIPS) using cell-free DNA has been assimilated into prenatal care. Prior studies examined clinical validity and technical performance in high-risk populations. This systematic evidence review evaluates NIPS performance in a general-risk population.MethodsMedline (PubMed) and Embase were used to identify studies examining detection of Down syndrome (T21), trisomy 18 (T18), trisomy 13 (T13), sex chromosome aneuploidies, rare autosomal trisomies, copy number variants, and maternal conditions, as well as studies assessing the psychological impact of NIPS and the rate of subsequent diagnostic testing. Random-effects meta-analyses were used to calculate pooled estimates of NIPS performance (P < .05). Heterogeneity was investigated through subgroup analyses. Risk of bias was assessed.ResultsA total of 87 studies met inclusion criteria. Diagnostic odds ratios were significant (P < .0001) for T21, T18, and T13 for singleton and twin pregnancies. NIPS was accurate (≥99.78%) in detecting sex chromosome aneuploidies. Performance for rare autosomal trisomies and copy number variants was variable. Use of NIPS reduced diagnostic tests by 31% to 79%. Conclusions regarding psychosocial outcomes could not be drawn owing to lack of data. Identification of maternal conditions was rare.ConclusionNIPS is a highly accurate screening method for T21, T18, and T13 in both singleton and twin pregnancies.     

荧光定量PCR检测孕妇外周血中游离胎儿DNA在子痫前期中的价值

目的探讨孕妇外周血中的游离胎儿DNA水平作为子痫前期预测指标的可能。方法普通PCR检测子痫前期孕妇22例和正常孕妇25例的血浆中Y染色体性别决定基因（SRY）,然后应用荧光定量PCR技术对有SRY基因表达者的胎儿DNA水平进行定量分析并比较子痫前期孕妇组和正常孕妇组胎儿DNA水平的差异。结果22例子痫前期患者及25例对照组中各有12例出现SRY阳性信号。子痫前期组的胎儿DNA水平明显高于正常对照组（P〈0.01）。结论孕妇外周血中的游离胎儿DNA可望作为预测子痫前期的指标之一。