Chorionic villi sampling: cytogenetic and clinical findings in 500 pregnancies

The cytogenetic findings were analysed in a series of 500 pregnancies in which chorionic villi sampling was performed. In all cases a direct method was used, karyotyping being successful in 481 cases (96.2%). The main indication for sampling was maternal age over 36 (412 cases; 82.4%). Abnormal laboratory findings resulted in 24 terminations of pregnancy (4.8%); in addition five unexpected balanced chromosome rearrangements were detected. Twelve of 15 cytogenetic discrepancies were detected at amniocentesis, two after termination, and one at spontaneous abortion. Complete follow up data were available for the first 250 patients, among whom nine pregnancies (3.6%) ended in spontaneous abortion before the 20th week. There were no false negative findings. Seventy additional chromosome studies were performed because of failure of chorionic villi sampling or equivocal results, or for confirmation. Counselling before chorionic villi sampling should include the possibility that subsequent amniocentesis may be needed should mosaicism or other unexpected abnormalities be found. The success rate and accuracy of karyotyping chorionic villi samples by the direct method are acceptable but distinctly less than those of karyotyping cultured amniotic fluid cells.     

Rapid aneuploidy testing (knowing less) versus traditional karyotyping (knowing more) for advanced maternal age: what would be missed, who should decide?

OBJECTIVES: The application of rapid aneuploidy testing as a stand-alone approach in prenatal diagnosis is much debated. The major criticism of this targeted approach is that it will not detect other chromosomal abnormalities that will be picked up by traditional karyotyping. This study aimed to study the nature of such chromosomal abnormalities and whether parents would choose to terminate affected pregnancies. DESIGN: Retrospective study on a cytogenetic database. SETTING: Eight public hospitals in Hong Kong. PARTICIPANTS: The karyotype results of 19 517 amniotic fluid cultures performed for advanced maternal age (>or=35 years) from 1997 to 2002 were classified according to whether they were detectable by rapid aneuploidy testing. The outcomes of pregnancies with abnormal karyotypes were reviewed from patient records. RESULTS: In all, 333 (1.7%) amniotic fluid cultures yielded abnormal karyotypes; 175 (52.6%) of these were detected by rapid aneuploidy testing, and included trisomy 21 (n=94, 28.2%), trisomy 18 or 13 (n=21, 6.3%), and sex chromosome abnormalities (n=60, 18.0%). The other 158 (47.4%) chromosomal abnormalities were not detectable by rapid aneuploidy testing, of which 63 (18.9%) were regarded to be of potential clinical significance and 95 (28.5%) of no clinical significance. Pregnancy outcomes in 327/333 (98.2%) of these patients were retrieved. In total, 143 (42.9%) of these pregnancies were terminated: 93/94 (98.9%) for trisomy 21, 20/21 (95.2%) for trisomy 18 or 13, 19/60 (31.7%) for sex chromosome abnormalities, and 11/63 (17.5%) for other chromosomal abnormalities with potential clinical significance. There were no terminations in the 95 pregnancies in which karyotyping results were regarded to be of no clinical significance. CONCLUSIONS: 'Knowing less' by the rapid aneuploidy stand-alone testing could miss about half of all chromosomal abnormalities detectable by amniocentesis performed for advanced maternal age. Findings from two fifths of the latter were of potential clinical significance, and the parents chose to terminate one out of six of the corresponding pregnancies. If both techniques are available, parents could have enhanced autonomy to choose.     

羊膜腔穿刺羊水细胞染色体检查用于高龄孕妇胎儿畸形预见性诊断分析

目的：探讨高龄孕妇进行孕中期羊膜腔穿刺羊水细胞培养染色体核型分析,提高对胎儿畸形的预见性诊断分析结果。方法随机选取该院2013年1月―2015年12月收治的714例高龄孕妇给予羊膜腔穿刺前的检查及超声诊断,行羊膜腔穿刺抽取羊水的孕妇,进行羊水细胞培养,制备染色体标本,分析高龄孕妇羊水胎儿细胞的染色体核型和胎儿染色体异常情况。结果该研究选取的714例高龄孕妇中染色体异常的分类有21三体综合征、18三体综合征、性染色体异常和其它的染色体异常。有23例高龄孕妇的染色体出现异常,检出率为3.22%;714例高龄孕妇中35~39岁占450例,发现胎儿染色体异常例数9例,检出率为2..00%为最低;44~46岁高龄孕妇占31例,发现胎儿染色体异常例数为3例,检出率为9.68%为最高。结论在产前对高龄孕妇进行羊膜腔穿刺羊水细胞染色体培养可以有效的检测胎儿的染色体异常情况,有效的对高龄孕妇分娩畸形胎儿进行预见性的诊断,明显降低新生儿的缺陷率。     

FISH技术在产前诊断中的应用价值研究

目的 使用荧光原位杂交（FISH）技术对常见胎儿染色体数目异常进行快速诊断,结合羊水细胞培养染色体核型分析技术形成产前诊断体系,并对其临床应用价值进行评价.方法 应用诊断最常见染色体病的5种染色体（13、18、21、X和Y）特异性FISH探针对480例未经培养羊水细胞进行产前诊断,并和同时进行的羊水培养染色体核型分析相比较.结果 480例未经培养羊水细胞FISH实验全部获得检测结果,并发现21-三体综合征2例,18-三体综合征1例,克氏综合征1例,特纳综合征 1例,与羊水培养染色体分析结果一致,但报告时间（2至3d）与羊水染色体分析报告时间（2~3周）相比大为缩短.受固有技术限制有6例结构异常未能检出,但应用FISH技术对其中1例与性染色体有关的结构异常进行辅助诊断,获得了成功.结论 FISH技术在常见染色体数目异常产前诊断中应用行之有效,与羊水染色体核型分析技术相结合,将使产前诊断更加高效和安全.     

CNV-Seq联合核型分析在羊水穿刺胎儿染色体嵌合体诊断中的应用

目的 探讨低深度基因组拷贝数变异测序（CNV-Seq）联合染色体核型分析在胎儿嵌合体诊断中的应用。方法 选取2018年1月至2019年9月在中国科学技术大学附属第一医院妇产科产前诊断中心行常规产前诊断的孕妇为研究对象，B超引导下行羊膜腔穿刺术获取羊水标本3 320份，所有标本均同时进行染色体核型分析（双线独立操作）及CNV-Seq，将诊断为胎儿染色体嵌合体的病例纳入回顾性分析。结果 3 320例穿刺羊水标本中，共检测出胎儿染色体嵌合体19例（阳性检出率为0.57%），其中，羊水核型检测出16例（阳性检出率为0.48%），CNV-Seq检测出12例（阳性检出率为0.36%）。无创产前检查提示异常的标本检出嵌合体8例，超声、胎儿颈项透明层厚度提示异常的标本检出嵌合体5例，孕妇高龄检出嵌合体2例，唐氏筛查结果提示高风险孕妇检出嵌合体4例。在2种方法联合检出的19例嵌合体中，性染色体嵌合9例，常染色体嵌合10例。3例核型分析无明显异常嵌合的病例，CNV-Seq技术检测出嵌合，后经荧光原位杂交证实其为真性嵌合。结论 CNV-Seq联合染色体核型分析，可以弥补单一检测方法诊断羊水穿刺胎儿染色体嵌合体出现误诊的不足，有望为产前遗传咨询提供更加可靠的实验室诊断结果。     

羊水染色体核型分析降低出生缺陷的研究

目的 探讨羊水染色体异常核型类型、分布及不同产前诊断指征的异常核型检出情况.方法 选取在保定市妇保健院具有产前诊断指征的孕妇1 305例,进行羊膜腔穿刺术及羊水染色体核型分析.结果 1 305例羊水标本共检出异常核型92例,检出率为7.05％,包括数目异常68例(73.91％)和结构异常24例(26.09％);异常核型...     

1134例不同指征的胎儿羊水染色体核型产前诊断分析

目的探讨具有不同产前诊断指征孕妇的染色体异常符合率,并评价母体外周血胎儿游离DNA无创产前基因检测（NIPT）作为产前一线筛查技术的临床应用价值。方法选取2017年1月至2019年3月有产前诊断指征的1134例孕妇为研究对象,在超声引导下行羊膜腔穿刺术,进行羊水细胞染色体核型分析。结果共检出异常染色体核型91例,异常检出率为8.02%（91/1134）。其中染色体数目异常（包括嵌合体）79例（21-三体46例、18-三体13例、13-三体4例、性染色体异常6例、嵌合体10例）,占86.81%（79/91）;染色体结构异常12例占13.19%（12/91）。不同产前诊断指征羊水核型异常结果符合率:NIPT阳性率为88.24%（45/51）最高（P < 0.01）,其次为超声筛查异常率为9.73%（P < 0.01）,血清学筛查高风险率为3.81%（28/735）,高龄发生率为3.42%（5/146）,超声筛查异常发生率为9.73%（11/113）,不良孕产史发生率为2.13%（1/47）,其他2.38%（1/42）等产前指征之间的符合率差异均无统计学意义（P>0.05）。结论产前血清学筛查（唐氏筛查）高风险是羊水穿刺的主要指征,孕中期NIPT可以为孕妇提供更加精准的筛查及优生指导。     

338例孕中期羊水细胞染色体核型结果分析

目的分析孕中期行产前诊断孕妇羊水细胞染色体核型,探讨羊水染色体检查对诊断胎儿染色体病的临床意义。方法对338例孕中期具有产前诊断指征的孕妇行羊膜腔穿刺术抽羊水进行细胞培养、G显带技术及染色体核型分析。结果羊水细胞培养成功率为100%。检出正常变异染色体36例(10.65%);检出异常核型13例(3.85%),其中数目异常9例,占异常核型的69.23%;结构异常4例,在异常核型中占30.77%。结论对具有产前诊断指征的孕妇进行羊水细胞染色体核型分析,能安全、有效地对胎儿染色体疾病进行产前诊断。     

应用荧光原位杂交技术对50例羊水标本产前诊断的研究

目的 探讨荧光原位杂交技术诊断未培养羊水细胞非整倍体的临床应用价值.方法 选用X、Y、13、18、2l号特异性探针对50例有产前诊断指征的孕妇进行羊水间期细胞的FISH分析及染色体核型分析.结果 被检50例羊水未培养细胞均获得诊断结果,检测出"21 三体"3例,检测结果与染色体核型分析及随访相符.结论 应用染色体特异性探针对羊水间期细胞进行FISH分析可用于胎儿染色体非整倍体的产前诊断,该方法具有快速、准确、灵敏度高的优点.     

染色体微阵列分析在染色体核型分析无法明确诊断病例中的应用价值

目的探讨染色体微阵列分析（chromosomal microarry analysis, CMA）在染色体核型分析无法明确诊断病例中的临床应用价值。 方法回顾性分析我院自2014年9月至2016年4月因染色体核型分析不能明确诊断而进一步进行CMA的48例病例（34例羊水标本,14例外周血标本）,对两种方法的检测结果进行比较。 结果48例病例中,核型分析提示13例为标记染色体,19例为衍生染色体,16例为染色体平衡易位。CMA共检出异常病例16例,异常率为33.33%。32例核型分析提示为标记染色体或衍生染色体的病例,CMA检测出大于5 Mb的缺失或重复16例,包括1例21-三体、2例XYY综合征及3例微重复/微缺失综合征（22q11重复综合征、Wolf-Hirschhorn综合征及15q26过度生长综合征）。16例核型分析为染色体平衡易位的病例,CMA均未发现阳性结果。 结论CMA可以明确定位核型分析发现的标记染色体或衍生染色体的来源,精确区分染色体不平衡易位和平衡易位。     

产前诊断中胎儿性染色体异常及临床分析

目的 探讨不同介入性产前诊断指征与胎儿性染色体异常之间的关系. 方法 对14680例行介入性产前诊断的孕妇制备胎儿染色体,分析胎儿性染色体异常与产前诊断指征的相关性. 结果 检出胎儿性染色体异常118例(0.80％),其中数目异常45例(38.14％,45/118),包括47,XXX 16例,45,X 14例,47,XXY 8例,47,XYY 7例;结构异常36例(30.51％,36/118),包括臂间倒位27例,易位2例,X长臂缺失2例,i(Xp)2例,i(Xq)及Yp+各1例;嵌合体37例(31.36％,37/118).118例中,产前筛查高风险50例,高龄38例,不良孕产史6例,超声异常28例,其中6例合并以上指征≥2个. 结论 各种介入性产前诊断指征对胎儿性染色体异常的检出均有重要价值.     

孕中期羊水细胞培养及其在产前诊断中的应用

目的:探索一种具有较高培养成功率的羊水细胞培养技术及其在产前诊断中的应用。方法:238例孕16～30周且有产前诊断指征的孕妇,在无菌条件下行羊膜腔穿刺术采集羊水进行细胞培养和染色体核型分析。实验过程对标本的采集、细胞接种收获和制片等环节进行了改进。结果:238例孕妇羊水成功培养231例,成功率97.1%,发现染色体异常核型8例,异常率占3.5%;其中染色体数目异常6例,嵌合体1例,平衡易位1例。结论:改进后的羊水细胞培养染色体核型分析技术是孕中期产前诊断胎儿染色体病的一种安全、有效、可靠的方法。     

胎儿心内强回声灶的临床价值

目的探讨胎儿心内强回声灶的临床价值。方法本研究对95例产前发现胎儿心内强回声灶孕妇进行临床追踪随访,并仔细进行胎儿心脏结构检查。对存在其他染色体高危因素的孕妇行羊水或脐静脉穿刺,进行胎儿染色体核型分析,其余孕妇在引产或分娩时取脐带静脉血进行染色体核型分析。结果 （1）95例孕妇中,存在染色体异常高危因素有13例,不伴其他高危因素者有82例。（2）95例孕妇进行了产前超声检查,3例被发现合并胎儿结构异常,其中1例为法络四联症,1例为十二指肠梗阻伴21-三体,1例为露脑畸形。（3）1例被发现胎儿染色体异常,为21-三体,发生于高危妊娠组（1/13,7.7%）。结论 （1）孤立存在的胎儿心内强回声灶与胎儿染色体异常、心脏畸形无明显相关性。（2）伴有其他染色体异常高危因素的胎儿有心内强回声灶时,胎儿染色体异常和心脏畸形的发生风险明显增高。     

大规模并行基因组测序技术应用于无创产前诊断染色体非整倍体的研究

目的利用大规模并行基因组测序技术检测孕妇外周血浆中的游离DNA,行胎儿染色体非整倍体的无创产前诊断。方法选择2009年1月到2010年7月在深圳市人民医院产前诊断中心就诊,孕龄在8～30周之间高龄妊娠、唐氏综合征生化筛查高风险和(或)彩超显示胎儿异常等同意介入产前诊断的孕妇941例,抽取孕妇外周静脉血,提取血浆DNA,制备测序文库,应用Illumina HiSeq2000高通量基因测序仪检测,测得的基因序列与人类的参考基因组比对并作统计分析。同时采集胎儿羊水或脐血,经细胞培养后行羊水或脐血细胞染色体核型分析确定染色体非整倍体。结果①941例孕妇血浆样本处理后经大规模并行基因组测序技术检测判定胎儿为唐氏综合征高风险共27例,非唐氏综合征914例;以羊水或脐血染色体核型分析的结果为金标准进行结果对照,检测出的27例唐氏综合征高风险中2例误诊,其中一例核型为47,XXY,一例核型分析正常。经统计分析胎儿唐氏综合征的检出率为100%,检出正确率99.78%,误诊率0.22%;②941例样本中,检出18-三体高风险14例,18-三体低风险927例。与染色体核型分析相比,统计分析显示无创产前基因检测18-三体胎儿的检出率为93.33%(14/15),漏诊率为6.67%(1/15)、误诊率为0。结论利用大规模并行基因组测序技术检测孕妇外周血浆中的游离DNA行无创产前诊断胎儿染色体非整倍体,其敏感性、特异性与染色体核型分析技术具有较高的一致性。该技术具有无创性、高准确性、高通量等优势,具有临床实际应用价值。     

孕期血清学筛查及超声检查在诊断胎儿染色体异常中的价值

目的探讨唐氏儿血清学筛查及超声检查在诊断胎儿染色体异常中的价值。方法对近3年我院5907例孕妇血清学筛查结果及40例因胎儿结构异常进行染色体检查的病例进行回顾性分析。结果5907例孕妇中检出唐氏儿高危病例521例（含82例年龄≥35岁的孕妇）,阳性率8.82%,共有198例进行了羊膜腔穿刺,穿刺率38%。40例胎儿畸形病例引产时取胎儿血或羊水进行染色体检查,成功率100%。共诊断17例胎儿染色体异常,其中21三体8例,18三体3例,13三体1例,1Turner综合征1例,Klinefelter综合征1例,18染色体短臂微缺失1例,9号染色体臂间倒位2例（1例来源于母亲）。17例中有8例进行了唐氏儿血清学筛查,5例异常,11例超声检查胎儿有结构异常。与染色体异常有关的畸形主要包括多发畸形、心脏畸形、胎儿水肿、消化道畸形等。结论应加强宣教,提高唐氏儿血清学筛查及高风险孕妇羊膜腔穿刺率;超声检查在胎儿染色体异常诊断中具有重要价值。     

Antenatal diagnosis of neural tube defects in Canada: extension of a collaborative study.

Experience with the diagnosis of neural tube defects from alpha1-fetoprotein (AFP) concentrations in amniotic fluid is reported from a prospective study of five laboratories testing for 13 Canadian genetic centres. The results of the study indicate that antenatal diagnosis of open neural tube defects is being carried out effectively in Canada (in 99.2% of cases the AFP measurements were interpreted correctly). Amniocentesis should be recommended to women at high risk for having a child with a neural tube defect (i.e., those who have a child, a parent or a sibling with a neural tube defect). The rate of neural tube defects in 182 high-risk pregnancies was 2.2% for an open defect and 1.1% for a closed defect, whereas the rate in 673 pregnancies in which amniocentesis was being performed for other reasons was 0.3%. This suggests that the AFP concentration should be measured in any sample of amniotic fluid collected for other reasons (usually fetal karyotyping). There were three instances of false-negative results, for a rate of 0.4%. Two closed neural tube defects were not detected; this limitation of the test has also been found by others. One of the six fetuses with an open neural tube defect, who died in utero, had a large myelocele in the neck that was not recognized. There were also four instances of false-positive results, for a rate of 0.5%. The findings suggest that AFP values that are more than 2 but less than 7 standard deviations (SDs) above the mean may indicate a neural tube defect, and that values 7 or more SDs above the mean very likely indicate such a defect, although other reasons for such high values (e.g., fetal erythrocytes in the amniotic fluid, intrauterine death and mistaken gestational age) must be ruled out by other methods.     

胎儿遗传病实验诊断标本采集方法的对比分析

目的探讨提高胎儿遗传病产前诊断准确性的不同标本采集方法。方法28例妊娠17—27周孕妇，在超声引导下单人徒手经母腹穿刺，同时取羊水、胎儿脐血行染色体、基因检查。结果羊水、胎儿脐血DNA进行短串联重复序列（STR）单体连锁分析5个位点排除母体细胞污染。羊水和脐血染色体、基因产前诊断结果一致性达100％。结论经母腹穿刺同时取羊水、胎儿脐血行胎儿遗传病产前诊断是减少误诊、漏诊、假阴性、假阳性的有效、可行的重要方法。     

四川地区21 723例早孕期唐氏综合征筛查报告

  目的  比较分析采用不同筛查方案对四川地区早孕期孕妇进行唐氏综合征产前筛查的筛查效率,探寻早孕期高效的唐氏综合征筛查方案。  方法  回顾性分析2011年1月至2017年12月于四川大学华西第二医院产前诊断中心接受早孕期血清学生化指标联合胎儿颈项透明层（NT）厚度筛查的单胎妊娠孕妇的结果。根据接受羊膜腔穿刺胎儿染色体检查的染色体结果及未接受羊膜腔穿刺的孕妇电话随访结果,了解胎儿染色体情况。比较分析孕妇年龄、NT厚度、血清学生化指标筛查、联合筛查这4种筛查方案对早孕期唐氏综合征的筛查效率。  结果  符合纳入标准的21 723例孕妇中,确诊唐氏综合征33例,18-三体综合征19例,性染色体异常4例及其他染色体异常8例。早期联合筛查唐氏综合征检出率72.73%,假阳性率2.49%;18-三体综合征检出率73.68%,假阳性率0.39%。对唐氏综合征而言,当假阳性率为5%时,以孕妇预产期年龄为筛查指标时,检出率为15.15%;以NT厚度为筛查指标时,检出率为57.58%;以早孕期血清学生化指标作为筛查方案时,检出率为60.61%;以早孕期联合筛查作为筛查方案时,检出率为87.88%。  结论  4种筛查方案中,早孕期联合筛查能够有效筛查出唐氏综合征胎儿,对其他染色体异常也有良好的筛查效果,是早孕期较好的产前筛查方案。     

胎儿鼻骨、颈项透明层厚度与母体血清学检测联合筛查唐氏综合征

目的  探讨孕早期鼻骨（NB）、颈项透明层厚度（NT）及孕中期母体血清甲胎蛋白（AFP）和游离β绒毛膜促性腺激素（free-β-HCG）检测在筛查唐氏综合征（DS）中的意义和作用。方法  对2010年3月-2014年6月来该院妇产保健门诊及住院的单胎孕妇共2 185例,于孕11～14周分别进行NB及NT测量,NB缺失为异常,NT≥3 mm为高危;所有孕妇均于孕15～21周进行母血清标志物AFP和free-β-HCG测定,利用DS产前筛查分析系统软件评估DS风险率,风险率≥1/270为高危。对筛查出的NB缺失、NT高危及DS高危孕妇进行遗传学咨询,在知情同意下进行羊膜腔穿刺羊水细胞染色体检查。对所有孕妇随访至妊娠结局,对A组（NB+NT）、B组（NB+血清学检查）、C组（NB+NT+血清学检查）筛查结果进行比较、分析。结果  联合筛查组（C组）筛查高危的DS发生率明显高于其余两组,与A、B两组比较,差异有统计学意义（P =0.043）。结论  在孕早期胎儿NB、NT、孕中期血清学3者联合筛查,可提高胎儿DS产前筛查的可靠性,使有创性诊断羊水穿刺更有针对性。

     

The prevention of Down's syndrome in the south western region of England 1975-1985

Cytogenetic prenatal screening for Down's syndrome in the South West Region of England from 1975 to 1985 was reviewed. The use of amniocentesis increased, and for the years 1981 to 1985 averaged 29.4% of women 35 years or over at their estimated date of delivery. 58 pregnancies were terminated after karyotyping of amniotic fluid cells confirmed trisomy 21. 385,440 live births were born in the region, 452 with Down's syndrome, giving a live birth incidence of 1 in 853. The effective impact of prenatal screening was calculated at an overall 8.3% reduction in Down's syndrome live births, but for the years 1981 to 1985 this rose to 11.3%. In spite of the introduction of new prenatal screening programmes that are not reliant solely on maternal age, it is predicted that substantial numbers of children with Down's syndrome are likely to be born each year. Adequate medical facilities will still be required for the survivors.