荧光定量聚合酶链反应技术快速产前诊断常见染色体非整倍体的临床应用

目的 探讨荧光定量聚合酶链反应(quantitative fluorescent polymerase chain reaction,QF-PCR)技术在快速产前诊断染色体非整倍体中的临床应用价值. 方法 分别选择21、18、13、X及Y染色体上的22个短串联重复序列(short tandem repeat,STR)位点及AMXY作为遗传标记,用QF-PCR技术对因唐氏综合征筛查高风险和高龄妊娠(≥35岁)行介入性产前诊断的1740例孕妇的绒毛或羊水样本进行检测,并同时进行染色体核型分析,比较并分析2种方法 检测结果 的符合率.结果 共有1690例产前诊断样本同时成功进行染色体核型分析和QF-PCR技术检测.所有QF-PCR检测报告均在48 h内得出.QF-PCR技术共检出染色体数目正常1649例,占97.57％;异常41例,占2.43％.其中染色体核型分析检测到的1639例正常病例,QF-PCR技术检测结果 均正常.染色体核型分析检测到51例染色体异常中,有41例用QF-PCR技术成功检测出,包括30例21-三体、6例18-三体、1例45,XO、1例47,XYY、1例47,XXX、1例69,XXX,1例47,XXY[94]/46,XY[6](QF-PCR技术检测结果 为47,XXY).QF-PCR技术对21、18、13、X及Y染色体非整倍体检出率100.0％,无假阳性.对于唐氏综合征筛查高风险和高龄妊娠人群,QF-PCR与染色体核型分析这2种方法 检测一致性可达99.4％ (1680/1690),该人群中2例染色体数目异常嵌合体、4例结构异常嵌合体及4例染色体结构异常病例QF-PCR技术未能检出,占总检测样本0.6％(10/1690).结论 QF-PCR技术能够快速、准确、经济、高效地产前诊断染色体非整倍体,对于21、18、13、X及Y染色体非整倍体检出率100.0％,对于唐氏综合征筛查高风险和高龄妊娠人群,QF-PCR可以准确和快速地为孕妇提供99.4％的诊断信息.     

唐氏综合征产前羊水诊断补救措施的探讨

目的对错过唐氏筛查和羊水胎儿细胞染色体核型分析的孕妇进行唐氏综合征产前诊断补救措施的探讨与研究。方法抽取首都医科大学附属北京妇产医院就诊的孕妇羊水3 ml共103例,均已诊断胎儿异常（染色体异常或大体畸形等）,提取羊水中胎儿细胞DNA,应用QF-PCR方法进行唐氏综合征的分子诊断。结果诊断周期48～72 h,诊断准确率达95%,孕周24～35周,年龄21～44岁,所有患者均进行了胎儿染色体的核型分析和QF-PCR法分析,其中9例为唐氏综合征胎儿。结论QF-PCR方法产前诊断妊娠24周以上的孕妇,与脐静脉穿刺血细胞培养染色体核型分析诊断相比,更安全,简便,快速,依从性好（妊娠24周以上已经不能进行羊水的胎儿细胞培养和核型分析）。     

多重荧光定量PCR方法的建立及其在快速产前诊断中的应用

目的 探讨用于快速产前诊断的多重荧光定量PCR(QF-PCR)方法的建立并评价其临床应用价值.方法 2008年5月到2009年7月在北京协和医院产前诊断中心进行产前诊断的孕妇170例,其中收集羊水123例,新鲜绒毛9例,脐血20例,自然流产绒毛18例.孕妇均为汉族,平均年龄(34.1±4.6)岁,平均孕周为(19.6±1.0)周.采用基因组DNA提取试剂盒提取羊水、绒毛及脐血标本中DNA.采用3种荧光素标记的引物,针对人类染色体中的短串联重复序列(STR)位点参照基因库(GenBank)和文献资料设计并合成20对引物,其中21号染色体6对引物,18号染色体4对引物,13号染色体4对引物,X和Y染色体1对通用引物,另有X染色体4对引物,Y染色体1对引物.设计检测方案为每份标本均进行两套8重QF-PCR(8×QF-PCR),共检测21、18、13号染色体及性染色体各4个位点;如果无法达到诊断要求,再追加第3套4个位点.同时与染色体核型分析结果进行对照.结果 (1)核型分析:170例标本均成功进行了核型分析,其中正常核型151例(89%,151/170),异常核型19例(11%,19/170).(2)QF-PCR检测:170例标本中,QF-PCR成功检测167例(98%),失败3例,QF-PCR检测均在2～3 d得出结果.QF-PCR检测结果正常134例,均与核型分析结果一致;核型分析异常的19例中,QF-PCR检测出异常18例(其中8例21三体及3例18三体).167例QF-PCR成功检测标本中,第1套+第2套引物组合共确诊150例(90%,150/167),加用第3套引物组合共检测3例(2%,3/167),另有14例不提供信息(8%,14/167).(3)QF-PCR诊断效率:QF-PCR用于常见非整倍体异常产前诊断的敏感度为95%(18/19),特异度为100%(134/134),假阳性率0(0/134),假阴性率5%(1/19),阳性预测值为100%(18/18),阴性预测值为99%(134/135).(4)QF-PCR检测常染色体及性染色体结果:21号常染色体STR位点中D21S1270和D21S1411杂合度最高,性染色体中DXS8377杂合度最高,扩增较稳定.结论 多重QF-PCR技术能成功用于常见非整倍体异常的快速产前诊断,检测结果准确,适合于规模较大的产前诊断中心进行大样本检测.     

STR-PCR在产前诊断胎儿唐氏综合征中的应用

目的:研究通过多重荧光定量PCR诊断胎儿染色体非整倍体用于临床快速产前诊断的可行性。方法:从孕中期羊水中提取胎儿DNA,通过多重荧光定量PCR使用STR对13、18、21号染色体进行非整倍体筛查,筛查结果异常者再进行快速诊断。用PCR诊断的羊水标本同时使用"金标准"染色体核型分析法做对比。结果:34例羊水标本中2例标本由于母血污染严重未行PCR检测,1例标本经PCR及核型分析均失败,29例标本经PCR和核型分析诊断为正常染色体,2例标本经PCR和核型分析诊断为21-三体。结论:通过STR-PCR法使用多重荧光酶联聚合反应探针产前诊断胎儿唐氏综合征是临床快速产前诊断的有效方法之一。     

QF-PCR技术检测4262例胎儿常见染色体非整倍体结果回顾分析

目的回顾分析荧光定量聚合酶链反应(quantitative fluorescence polymerase chain reaction,QF-PCR)技术对常见染色体(21、18、13、X/Y)非整倍体产前诊断的结果,评价其应用价值。了解不同产前诊断指征诊断为常见染色体非整倍体的阳性率,从而对遗传咨询提供参考依据。方法选取2018年1月至2018年12月在广东省妇幼保健院进行产前诊断的标本4262例,用QF-PCR和染色体核型分析的方法双盲检测,统计QF-PCR的符合率、灵敏度和特异度及不同产前诊断指征诊断为染色体非整倍体的阳性率。结果与金标准染色体核型分析比较,QF-PCR快速诊断常见染色体(21、18、13、X/Y)非整倍体阳性数305例,漏诊4例低比例非整倍体嵌合体,另外有1例21-三体嵌合体QF-PCR阳性,而核型分析阴性,符合率98.8%,灵敏度和特异度分别为85.9%和99.9%,剔除常见5条染色体非整倍体检测范围以外的阳性标本,灵敏度和特异度分别为98.7%和99.9%。不同的产前诊断指征中诊断为常见染色体非整倍体的阳性率:无创产前基因筛查高风险(77.6%);颈项透明层厚度增厚(10.7%);胎儿超声异常(9.0%);唐氏综合征血清学筛查高风险(8.2%);孕妇年龄≥35岁(4.4%);高危妊娠(3.9%);不良孕产史(1.0%)。结论QF-PCR快速诊断常见染色体(21、18、13、X/Y)非整倍体,灵敏度和特异度高,但对低比例嵌合体非常容易漏诊,两种结果不符合时,不能完全依靠染色体核型分析诊断,了解不同产前诊断指征的阳性率,对遗传咨询有一定的指导价值。     

短串联重复序列聚合酶链反应技术快速诊断常见染色体三体的价值

目的探讨短串联重复序列聚合酶链反应技术(STR-PCR)诊断染色体三体应用价值。方法2003年12月至2005年2月对广州医学院第三附属医院染色体结果已知的50例正常样本和17例唐氏综合征(Down's)患者样本进行STR-PCR检测。结果50例正常样本的21、18、13号染色体数目检出符合率为82%、96%、96%,假阳性率为2%;17例唐氏综合征患者的检出率为100%;11例Down's患者家庭中,除3例额外的21号染色体来源不能判定外,8例均来源于母亲,其中7例来源减数分裂Ⅰ不分离,1例来源减数分裂Ⅱ不分离。结论STR-PCR技术可以快速诊断Down's等常见染色体三体,并判断额外染色体的来源及发生阶段。     

实时荧光定量聚合酶链反应技术在产前诊断唐氏综合征中的应用

目的探讨实时荧光定量PCR技术用于产前诊断唐氏综合征的可行性。方法采用实时荧光定量PCR法,分别检测85例唐氏综合征高风险的中期妊娠妇女的羊水和7例智残儿外周血标本中,21号染色体上特异区域基因片段(DSCR3)和管家基因片段(GAPDH),并计算两者的比值。同时采用细胞遗传学方法分析其染色体核型。结果80例羊水细胞DNA检测DSCR3／GAPDH比值在0．46—1．30之间,染色体核型全部正常;而另5例羊水细胞和7例智残儿外周血DSCR,／GAPDH比值明显升高,达1．64～1．98,染色体核型均为21三体。5例中有3例核型为47,XY, 21;1例核型为47,XX, 21;另1例为易位型[46,XY,-15, t(15;21)]。7例智残儿中4例为47,XY 21;3例为47,XX 21。结论实时荧光定量PCR技术可作为产前快速准确诊断唐氏综合征的有效方法。     

基于染色体短串联重复序列的荧光定量PCR技术在产前诊断中的实际应用

目的 本研究旨在探讨基于染色体短串联重复序列(short tandem repeat, STR)的荧光定量PCR(quantitative fluorescence PCR,QF-PCR)在产前诊断中的应用潜力及其价值。方法 通过基于STR的QF-PCR技术结合染色体核型分析技术和染色体微阵列分析技术(chromosomal microarray analysis, CMA),我们对635例产前筛查异常的羊水样本进行了筛查,从而有效地排除了母源细胞污染(maternal cell contamination, MCC)(>20%),为后续的产前检测提供了可靠的依据。此外,为了快速诊断胎儿及其相应的孕妇样本,我们检测了包括13、18、21、X、Y在内的五条染色体,并将其与核型分析的结果进行比较。结果 通过QF-PCR检测,在635例样本中,发现了3例母源污染,1例三倍体,1例与母亲的亲缘关系不符,12例21三体,6例18三体,1例13三体。除此之外,还有10例性染色体异常和1例21三体嵌合。与CMA结果比较,QF-PCR检测结果均符合试剂盒的检测范围。值得一提的是,QF-PCR检测...     

高龄孕妇胎儿基因组拷贝数变异发生率研究

目的探讨应用基因组拷贝数变异测序(CNV-seq)技术检测高龄孕妇羊水中基因组拷贝数变异(CNV)的发生率。方法收集2018年1月1日至12月31日因年龄高风险在哈尔滨医科大学附属第一医院应用羊膜腔穿刺术进行产前诊断的孕妇羊水标本247例。对胎儿羊水细胞进行G显带染色体核型分析的同时应用CNV-seq检测羊水细胞基因组DNA,统计在羊水染色体核型分析正常的高龄孕妇中CNV的发生率。结果 247例羊水标本中,染色体核型分析和CNV-seq同时检测出染色体非整倍体共计21例,其中21-三体综合征14例,18-三体综合征2例,13-三体综合征1例,性染色体非整倍体4例。染色体核型分析检出性染色体非整倍体1例(为45,XO[3]/46,XX[97]);染色体结构异常9例,其中染色体易位4例,染色体正常变异3例,2例染色体结构异常经CNV-seq检测最终确定异常片段的来源。染色体核型异常总检出率为12.55%(31/247)。在216例染色体核型结果正常的羊水标本中,CNV-seq额外检出明确致病CNV 4例,临床意义未明的染色体微缺失6例(其中1例为父源,1例为母源,其余4例未进行夫妇验证),CNV多态性15例。羊水样本中CNV的总检出率为19.43%(48/247),CNV-seq比染色体核型分析额外增加了6.88%的检出率,其中明确致病的CNV检出率为1.62%(4/247)。结论对进行有创产前诊断的高龄孕妇,在排除了常见的非整倍体异常后也应建议进行CNV检测。     

多重定量荧光PCR在常见染色体非整倍体疾病快速产前诊断中的应用研究

目的:建立适合于中国人群特点的常见染色体非整倍体疾病快速产前诊断技术。方法:随机抽取50例正常无关个体的外周静脉血和9例羊水标本以及3例血清学筛查为阳性的胎儿羊水,应用定量荧光PCR技术分析13、18、21、X/Y染色体上的短串联重复序列(STR)的多态信息含量(PIC)。结果:中国人13、18、21、X/Y染色体上STR:D13S631、D13S634、D13S742、D18S386、D18S391、D18S535、D21S11、D21S1270、IFNAR、X22、XHPRT的PIC分别为0.800、0.749、0.821、0.914、0.623、0.760、0.876、0.848、0.848和0.807。应用以上STR对血清学筛查阳性的胎儿羊水DNA标本进行诊断,证实了18-三体综合征、21-三体综合征和Klinefelter综合征胎儿各1例,与染色体核型分析结果相一致。结论:本文研究所选STR位标在中国人群中呈现较高的遗传多态性,符合Hardy-Weinberg平衡定律,建立了快速产前诊断常见染色体非整倍体疾病的多重定量荧光PCR技术。     

Introduction of the QF-PCR analysis for the purposes of prenatal diagnosis in Bulgaria--estimation of applicability of 6 STR markers on chromosomes 21 and 18

OBJECTIVE: The aim of our study was to estimate the observed heterozygosity and informativeness of 6 STR markers on chromosomes 18 and 21 in the Bulgarian population. We have evaluated the applicability of these markers used from other investigators for QF-PCR prenatal diagnosis of the most common autosomal aneuploidies in Bulgaria. METHODS: DNA samples (n = 486) were extracted from different fetal tissues (amniotic fluid cells, chorionic villus samples, and fetal tissue after abortions). PCR amplifications of 4 STR markers located on chromosome 21 (D21S11, D21S1411, D21S1270, and D21S1440) and 2 on chromosome 18 (D18S535 and D18S51) were performed. They were analysed on an automated sequencer, and the allele dosage ratios were calculated. RESULTS: The results indicate the selected markers as highly informative for our population and suitable for QF-PCR prenatal diagnosis in Bulgaria. All samples with trisomy 21 (n = 8), trisomy 18 (n = 4) and triploidy (n = 1) were correctly detected by our analysis. Thus, no false-negative results were observed. CONCLUSION: QF-PCR analysis could be an applicable alternative in prenatal and postnatal diagnosis in cases with a strong suspicion for particular autosomal aneuploidies (including chromosomes 21, 18, and 13) in small countries with limited resources like Bulgaria.     

Prenatal diagnosis of common aneuploidies using multiplex quantitative fluorescent polymerase chain reaction

OBJECTIVE: Prenatal diagnosis of foetal trisomies is usually performed by cytogenetic analysis. This requires lengthy laboratory procedures and it is expensive. Here, we report a retrospective study of quantitative fluorescent polymerase chain reaction (QF-PCR) for prenatal detection of trisomies 13, 18 and 21. METHODS: QF-PCR was performed on a total of 447 amniotic fluids blindly analysed without any knowledge of the cytogenetic results and 43 samples with known karyotype. All samples were tested with at least 4 small tandem repeat markers specific for each chromosome 13, 18 or 21. RESULTS: QF-PCR results on amniotic fluid were consistent with conventional cytogenetic data. QF-PCR detected 5 cases of trisomy 21, 2 cases of trisomy 18, 1 case of trisomy 13 and 1 case with Klinefelter's syndrome. CONCLUSIONS: QF-PCR has proved to be very useful in clinical settings, since it allows the detection of major numerical disorders in a few hours after sampling and thus reduces parental anxiety.     

定量荧光PCR在唐氏综合征快速产前诊断中的应用研究

目的 :了解中国人 D2 1 S1 1、D2 1 S1 2 70、D2 1 S2 2 6、D2 1 S1 41 1四个短串联重复序列 ( STR)位点的多态性信息含量 ( PIC) ,建立定量荧光 PCR快速产前诊断唐氏综合征的方法。方法 :以染色体2 1 q2 1～ q2 2 .3区段内四个短串联重复序列作为遗传标记 ,采用定量荧光 PCR对 5 0例正常人外周血 DNA进行分析 ,计算中国人该四对 STR位标的多态性信息含量 ( PIC) ,并用该方法对 1 1例正常孕妇羊水 DNA进行分析 ,及对唐氏综合征血清生化指标筛查阳性孕妇羊水标本进行产前诊断。结果 :D2 1 S1 1、D2 1 S1 2 70、D2 1 S2 2 6、D2 1 S1 41 1的多态性信息含量分别是 0 .90 2、0 .889、0 .5 2 1、0 .775 ,建立了定量荧光 PCR产前诊断唐氏综合征的方法。应用该技术产前诊断出 3例唐氏综合征患儿 ,并经染色体核型分析所证实。结论 :以上四对 STR在中国人中均具有较高多态性信息含量 ,可应用于唐氏综合征的定量荧光 PCR产前诊断技术中     

Rapid prenatal diagnosis of common trisomies: discordant results between QF-PCR analysis and karyotype analysis on long-term culture for a case of trisomy 18 detected in CVS

OBJECTIVES: QF-PCR analysis can be used as a rapid test to diagnose primary trisomy in prenatal samples. Mosaicism in CVS detected by QF-PCR has previously been reported; however, no case has so far been reported in which the QF-PCR result was completely discrepant to that of the karyotype analysis from a long-term culture. METHODS: A CVS, referred because of a high serum screening risk of 1:10 for Down Syndrome and 1:110 for Edwards Syndrome, was tested by QF-PCR analysis and chromosome analysis of cultured cells. Subsequent analyses were carried out on a follow-up amniotic fluid sample and foetal tissue samples. RESULTS: Conflicting results were obtained between QF-PCR analysis on two independent fronds from the chorionic villi and chromosome analysis on cultured CVS. Cytogenetic and molecular analysis on a subsequent amniotic fluid sample indicated trisomy 18 with no evidence of mosaicism. Analysis of follow-up tissue confirmed trisomy in a foetal skin sample and mosaicism for trisomy 18 in four placental sites tested. CONCLUSION: We report here an apparently normal CVS QF-PCR result that was completely discrepant with the trisomy 18 positive karyotype result on long-term culture. This has important implications regarding our current testing protocol.     

Maternal cell contamination of prenatal samples assessed by QF-PCR genotyping

OBJECTIVES: To establish the genotype of cultured cells from a cohort of amniotic fluid and chorionic villus samples, and compare this genotype with that obtained from uncultured material from the same sample, in order to assess the frequency and significance of maternal cell contamination of prenatal samples. METHODS: Quantitative fluorescence-polymerase chain reaction (QF-PCR) was carried out by amplification of microsatellite markers using fluorescence-labelled primers, followed by quantitative analysis of the allele peaks on a genetic analyser. A multiplex of 12 primer pairs for four loci on each of chromosomes 13, 18 and 21 was used. RESULTS: A total of 307 prenatal samples were tested. Of the 254 amniotic fluid samples, 39.8% had some degree of bloodstaining, ranging from 5% bloodstaining in the cell pellet to heavily bloodstained fluid. Uncultured samples were tested by QF-PCR analysis and the cultured cells were tested by both QF-PCR and karyotype analysis. Of the samples, 90.2% had the same single genotype on direct and cultured material. Two samples (0.65%) were mosaic for an aneuploidy cell line. A second genotype, interpreted as maternal cell contamination, was identified in direct and/or cultured preparations in 9.1% of samples, 17.8% of which were not bloodstained. Seven amniotic fluid samples (2.8%) showed maternal cell contamination in cultured material. CONCLUSIONS: For heavily bloodstained amniotic fluid samples, a maternal blood specimen may help interpret the results of rapid trisomy testing, followed by confirmation of the fetal origin of cultured cells. QF-PCR analysis has established a higher incidence of maternal cell contamination of cultured amniocytes than previous reports; the presence of MCC (maternal cell contamination) in cultured cells from samples with no bloodstaining underlines the need for karyotype analysis of more than one XX culture.     

The consanguinity effect on QF-PCR diagnosis of autosomal anomalies

OBJECTIVES: Quantitative Fluorescent PCR (QF-PCR) is a simpler and faster method of detecting common chromosomal abnormalities when compared to cytogenetic analysis. The aim of our study is to investigate the applicability of this methodology in a population where consanguineous marriages are common and to estimate the heterozygous frequency of the PCR markers used. METHODS: Four hundred and twenty-three DNA samples were extracted from uncultured amniocytes and amplified with 18 short tandem repeats (STR) markers specific to chromosomes 13, 18 and 21. Amplification products were analyzed using the GeneScan software. RESULTS: QF-PCR correctly identified all the numerical abnormalities related to chromosomes 13, 18 and 21. A total of 24 autosomal trisomies (5.7%) were detected. The markers D21S1432 and D21S11 were the most consistent in providing unequivocal positive results for chromosome 21 and the heterozygosity percentages of the markers used were lower than the values reported in Western populations. CONCLUSION: QF-PCR is reliable for the prenatal diagnosis of numerical anomalies of the chromosomes 13, 18 and 21 in our study population. The absence of STR heterozygosity data from Lebanon and surrounding countries makes our study very useful for the development of a reliable QF-PCR trisomy detection test.     

Detection of mosaicism for primary trisomies in prenatal samples by QF-PCR and karyotype analysis

OBJECTIVES: QF-PCR can be used to rapidly diagnose primary trisomy in prenatal samples. Our objectives were to estimate the prevalence of primary trisomy mosaicism for chromosomes 13, 18 or 21 in a cohort of prenatal samples, and to compare and contrast the detection of this mosaicism using both QF-PCR and karyotype analysis. METHODS: Data was collated from all prenatal samples displaying mosaicism for a primary trisomy between June 2000 and March 2004. Levels of mosaicism were estimated and samples were categorised according to the cell population in which the mosaicism was detected. RESULTS: In a total of 8983 samples, 18 samples (0.20%) displaying mosaicism were detected, including trisomy 13 (three samples), trisomy 18 (seven samples), trisomy 21 (seven samples) and mosaic triploidy (one sample). This included 7 amniotic fluid and 11 chorionic villus samples. Mosaicism was detected by QF-PCR in 12 samples and by karyotype analysis in 8 samples. CONCLUSIONS: QF-PCR can detect mosaicism when the abnormal cell line contributes at least 15% of the whole sample. Use of both karyotype and QF-PCR analysis leads to the detection of more cases of mosaicism than either test alone.     

Rapid prenatal diagnosis of aneuploidies and zygosity in multiple pregnancies by amniocentesis with single insertion of the needle and quantitative fluorescent PCR

OBJECTIVE: To investigate amniotic fluid (AF) samples retrieved in multiple pregnancies by single insertion of the needle, for rapid assessment of chromosome copy number, zygosity, and cross-contamination between fetuses, using Quantitative Fluorescent Polymerase Chain Reaction (QF-PCR) amplification of highly polymorphic microsatellite markers. METHODS: Fifty-two multiple pregnancies were selected (47 twins, 5 triplets) and 108 samples of amniotic fluid were sampled between 12 to 20 weeks of gestation (mean 15.5) using the single-needle technique. Aneuploidy screening by QF-PCR amplification of short tandem repeats (STRs) on chromosomes X, Y, 21, 13, and 18 was carried out within 24 h of collection. Owing to the sampling procedure, the eventual presence of contamination between fetuses was also evaluated in every case. RESULTS: Normal and aneuploid fetuses were readily identified by QF-PCR. Fetal reduction was made available, for trisomic fetuses, without further waiting for completion of fetal karyotyping. In twin gestations, the ultrasound examination of chorionicity was always in agreement with the molecular assessment of zygosity. Contamination between fetuses due to the sampling procedure with a single puncture was never observed. CONCLUSION: Rapid prenatal diagnosis of aneuploidies by QF-PCR is a sensitive, efficient, and reliable assay. When applied in multiple pregnancies, it has the added value of allowing the assessment of zygosity in all cases, independently of chorionicity and fetal sex.