细菌人工染色体标记-微球鉴别/分离法对1973份羊水的快速产前诊断

目的探讨细菌人工染色体标记-微球鉴别/分离法(bacterial artificial chromosomes-on-beads,BoBs)在产前诊断中的应用价值。方法对2015年1月至2016年6月西京医院产前诊断中心1973例有产前诊断指征的孕妇羊水细胞进行BoBs检测和染色体核型分析。结果 1973例羊水中,共发现异常核型150例,其中染色体核型分析检出145例,BoBs检出133例。不同产前诊断指征下,无创DNA产前检测(NIPT)高风险组的染色体异常检出率最高,占该指征的81.82%。150例异常核型中,BoBs和核型分析均检出染色体非整倍体124例,占异常核型的82.67%;BoBs检出染色体微缺失/微重复综合征5例,核型分析结果均未见异常;染色体核型分析检出性染色体嵌合7例,BoBs检出4例;染色体核型分析检出结构异常14例,BoBs结果未见异常。结论 BoBs技术可以快速检测染色体非整倍体和基因微缺失/微重复,联合染色体核型、基因芯片(chromosomal microarray analysis,CMA)及荧光原位杂交技术(fluorescence in situ hybridization,FISH)可对染色体结构异常和低嵌合正确检出,大大提高了产前诊断的效率与准确性。     

应用荧光原位杂交产前诊断染色体异常的临床价值

目的:探讨应用荧光原位杂交(HSH)产前诊断染色体非整倍体的临床价值.方法:收集120例产前诊断孕妇的新鲜羊水进行FISH检测和染色体核型分析,并将结果与临床追踪确诊结果(随访的新生儿或引产的死胎脐血或外周血的染色体核型)作比较,同时根据FISH的检测效能和分析产前诊断方案,评价HSH的临床应用价值.结果:①HSH检测全部成功,其结果与临床追踪确诊的核型分析一致,并且染色体非整倍体检出率100%;1例孕晚期羊水细胞培养失败,2例羊水培养为四倍体镶嵌体胎儿经临床追踪确诊后为正常染色体.②产前诊断指征中,高龄、多项指征及其他因素的孕妇临床上对FISH及核型分析这两种方法的选择比较,差异无统计学意义(P>0.05);而血清唐氏筛查异常和超声筛查异常的孕妇分别倾向选择FISH(P=0.029)及核型分析(P=0.000).结论:HSH技术能快速准确检测染色体非整倍体的异常.母血清唐氏筛查异常孕妇产前诊断倾向选择FISH检测.FISH可作为孕晚期高危孕妇首选的产前诊断方法.     

系列遗传学检测法评估真性胎儿染色体嵌合体的价值

目的探讨染色体核型分析、染色体微阵列分析(chromosomal microarray analysis, CMA)及荧光原位杂交(fluorescencein situ hybridization, FISH)技术在真性胎儿染色体嵌合体产前诊断中的应用价值。方法 2018年4月至2021年8月, 有明确产前诊断指征并在中山大学附属第一医院行羊膜腔穿刺术或/和脐静脉穿刺术产前诊断的单胎妊娠孕妇共4 071例, 其中产前诊断为胎儿真性染色体嵌合体的40例孕妇纳入回顾性分析。分析其染色体核型分析、CMA及FISH结果及嵌合染色体分布、嵌合比例及妊娠结局。采用χ2检验进行统计学分析。结果 (1)真性胎儿染色体嵌合体的检出率为0.98%(40/4 071)。(2)性染色体嵌合体占42.5%(17/40), 其他染色体嵌合体包括21、22、18、16、7、12、15、17和20号染色体及染色体平衡易位嵌合。(3)真性胎儿染色体嵌合体在羊水染色体核型分析中的检出率为77.4%(24/31);在羊水CMA中的检出率为76.7%(23/30);在脐血染色体核型分析中的检出率为10/19;在脐血CMA中...     

234例羊膜腔穿刺诊断胎儿染色体异常的研究

目的评价羊水穿刺术在产前诊断胎儿染色体异常中的应用。方法对234例有产前诊断指征的孕妇在超声引导下经腹羊膜腔穿刺抽取羊水检查染色体核型,并比较不同产前诊断指征分组的异常染色体检出率。结果全部病例穿刺均成功,羊水细胞培养成功率97.86%,染色体异常检出率5.68%。其中超声示胎儿异常组染色体异常检出率(33.33%)明显高于21-三体高风险组(4.54%)、不良孕产史组的检出率(9.09%)(P<0.05)。结论超声引导下经腹羊膜腔穿刺抽取羊水在产前诊断中是成熟有效的操作技术,孕妇血清学筛查异常、不良孕产史、超声示胎儿异常是有效的穿刺指征,其中胎儿异常的超声监测对产前诊断提示胎儿染色体异常具有较好的预测性。     

1180例羊膜腔穿刺产前诊断的异常染色体检出率及安全性分析

目的:探讨羊膜腔穿刺产前诊断异常核型发生的频率、类型及其与产前诊断指征的关系,并对羊膜腔穿刺术的安全性进行评估.方法:回顾性分析我院2005年1月至2008年8月1180例羊膜腔穿刺的手术指征、不同指征的异常染色体检出率及穿刺相关并发症.结果:1180例羊膜腔穿刺产前诊断中,发现异常核型43例,异常检出率为3.6%.43例中染色体数目异常19例,占异常核型的44.2%,其中21-三体10例,占异常核型23.3%.异常染色体检出率由高到低依次为:夫妇一方染色体异常携带、不良孕产史、孕中期母血清血两联法筛查高风险、超声检查胎儿结构异常、孕妇高龄.高龄孕妇中21-三体检出率为0.5%(2/410),非高龄组为1.0%(8/770),P>0.05,差异无统计学意义.1180例羊膜腔穿刺产前诊断中共有5例流产,经分析其原因与羊膜腔穿刺无关.结论:超声引导下羊膜腔穿刺是一种安全可靠的产前诊断方法.严格把握产前诊断指征,积极实施二级干预是提高人口素质的重要措施.     

荧光原位杂交技术及染色体核型分析在产前诊断中的应用价值

目的探讨与羊水细胞染色体核型分析相比,荧光原位杂交(fluorescence in situ hybridization,FISH)技术在产前诊断中的优缺点及临床应用价值。方法对2009年1月至2010年2月华中科技大学同济医学院附属同济医院208例孕妇抽取羊水体外培养后进行染色体核型分析,其中53例同时应用FISH技术直接对间期核细胞进行13、18、21、X、Y的染色体数目检测。结果 (1)208例中,共完成羊水细胞核型分析199例,诊断成功率为95.7%(199/208),其中异常染色体核型占8.04%(16/199),报告时间平均为(22.49±6.12)d。(2)同时进行核型分析和FISH检测的53例患者,核型分析及FISH诊断成功率均为100%,共发现染色体异常4例,占7.55%(4/53);其中结构异常3例(经核型分析诊断)、数目异常1例(核型分析及FISH均诊断成功)。(3)在染色体数目的诊断上,53例的FISH检测与染色体核型分析的一致率为100%,平均报告时间为2～4d。结论 (1)FISH技术应用于产前诊断染色体数目异常,成功率高,准确可靠,较常规核型分析方法有效缩短报告时间。(2)对于可...     

荧光原位杂交在未培养羊水细胞产前诊断中的临床应用研究

目的:建立稳定的荧光原位杂交(FISH)技术,探讨FISH技术在未培养羊水细胞产前诊断的-临床应用价值.方法:应用国产5条染色体探针(13、18、21、X、Y)对411例有产前诊断指征的孕妇进行未培养羊水细胞的FISH检测,同时进行细胞染色体核型分析,对两者检测结果进行比较.结果:411例中,正常核型398例,非整倍体核型5例(均为21-三体),结构异常4例(平衡易位2例、倒位2例),染色体多态4例.其中正常核型及5例非整倍体核型能被FISH检测出,而染色体结构异常和染色体多态未能检测出;FISH检测时间为48～72小时,较传统核型分析时间(14～21天)大大缩短;FISH检测一次成功率97.3%,并且不受孕周的限制;FISH检测与细胞培养核型分析相符;FISH检测没有受到羊水性状的影响;染色体非整倍体的诊断准确率达100%.结论:应用国产探针对未培养羊水细胞进行FISH分析,实验方法简便快速,可用于染色体非整倍体的产前诊断,有较大的临床应用价值.     

羊水细胞染色体产前诊断3495例结果分析

目的 探讨各种细胞遗传学产前诊断指征与胎儿染色体异常的关系。方法 2011年1月至2013年4月于重庆医科大学附属第一医院妇产科在知情同意的前提下,由超声引导对3495例孕中期高危孕妇（孕16~21+6周）行羊膜腔穿刺术,抽取适量羊水进行细胞培养及染色体核型分析。比较不同产前诊断指征与胎儿染色体异常核型检出率的关系。 结果 羊水培养成功3494例,成功率99.97%。检出异常核型120例,异常率为3.43%（120/3494）,其中染色体数目异常70例,结构异常31例,其他异常19例。各种产前诊断指征中,单纯高龄（分娩时孕妇年龄≥35岁）1498例,检出异常核型47例,异常检出率为3.14%;母血清学筛查高风险1560例,异常核型38例,检出率2.44%;无创产前DNA检测高风险38例,异常核型30例,检出率78.95%,后者检出率分别与前两者相比差异有统计学意义（P<0.05)。结论 掌握好各种产前诊断指征,对高危孕妇进行羊膜腔穿刺及染色体核型分析可有效提高胎儿染色体病的检出率,减少出生缺陷的发生。     

不同指征介入性产前诊断的异常染色体检出率及其安全性分析

目的 探讨不同指征介入性产前诊断(羊膜腔穿刺和脐血管穿刺)的异常染色体检出率以及介入性产前诊断技术的安全性. 方法回顾性分析本中心1264例介入性产前诊断(1082例羊膜腔穿刺和182例脐血管穿刺)的手术指征、不同指征的异常染色体检出率及穿刺相关并发症.结果 1264例介入性产前诊断中,穿刺指征分别为:血清学筛查高风险651例(51.5%)、孕妇高龄(年龄≥35岁)318例(25.2%)、超声胎儿结构异常136例(10.8%)、不良妊娠史88例(6.9%)、血清学筛查一项或两项标志物MoM值异常52例(4.1%)和夫妇一方染色体平衡易位携带19例(1.5%).共检出有临床意义的染色体异常37例,其穿刺指征依次为:超声提示胎儿结构异常20例(20/136,14.7%),血清学筛查高风险12例(12/651,1.8%),至少一项标志物MoM值异常1例(1/52,1.9%),不良妊娠史1例(1/88,1.1%),夫妇一方染色体平衡易位携带3例(3/19,15.8%),孕妇年龄≥35岁者未检出有临床意义的染色体异常(0/318).1264例介入性产前诊断中共有5例自然流产,其中与羊膜腔穿刺相关的胎儿丢失率为0.28%(3/1082),与脐血管穿刺相关的胎儿丢失率为1.09%(2/182),两者相比差异无统计学意义(P=0.154).脐血管穿刺后孕妇心慌、腹痛以及胎心减慢等并发症的发生率明显高于羊膜腔穿刺组(9.89%和0.18%,P=0.001). 结论超声发现胎儿结构异常应常规检查胎儿核型;单纯高龄作为介入性产前诊断的指征值得商榷;介入性产前诊断从安全性角度应首选羊膜腔穿刺术.     

细菌人工染色体标记-微球鉴别/分离法在产前诊断中的临床应用价值

目的:探讨细菌人工染色体标记-微球鉴别/分离法(BoBs)在产前诊断中的临床应用价值。方法:对2015年1月至2018年4月空军军医大学第一附属医院4882例有产前诊断指征的孕妇羊水细胞行染色体核型分析和BoBs检测,检测结果进行比较分析。结果:4882例羊水中共检出胎儿染色体异常289例,异常检出率5.92%。其中染色体核型分析检出271例,BoBs检出266例。不同产前诊断指征下,无创产前检测高风险组的染色体异常检出率最高,占56.00%。289例异常核型中,染色体非整倍体239例,BoBs检测结果与染色体核型分析结果吻合;染色体微缺失/微重复综合征21例,染色体核型分析仅检出3例;性染色体嵌合11例,BoBs检出6例;染色体结构异常18例,BoBs均未检出。结论:BoBs技术是一种可靠的检测技术,可以全面快速检测胎儿染色体非整倍体及9种常见的微缺失/微重复综合征,与染色体核型分析联合可以提高产前诊断的效率及准确性,具有较高的临床应用价值。     

Chorionic villus sampling (CVS) and fluorescence in situ hybridization (FISH) for a rapid first-trimester prenatal diagnosis

OBJECTIVES: Early diagnosis of unbalanced chromosomal abnormalities can be crucial in minimizing the trauma caused by an elective abortion. Chorionic villus sampling (CVS) can be performed from 9 weeks of gestation. However, two major problems are encountered in fetal karyotyping using cultured cells from chorionic villi: the relatively slow growth of these cells in culture, which delays the diagnosis, and the occurrence of maternal cell contamination (MCC). With FISH, a result can be obtained within 24 h, and, as no cell culturing is involved, the problem of MCC is minimized. METHODS: Thirty-two women undergoing CVS between 9 and 12 weeks of gestation were offered FISH analysis in addition to the standard chromosome analysis. RESULTS: FISH was informative in all of the cases tested. Eleven aneuploidies were detected in cases of hygroma or abnormal nuchal translucency and two out of four fetuses from parental translocation were unbalanced. The decision to perform early termination of these chromosomally abnormal pregnancies was based on FISH results and ultrasound abnormalities, without waiting for karyotype results. CONCLUSION: The present study confirms that the association of FISH and CVS allows a rapid and early prenatal diagnosis, and emphasizes that this association is of great benefit in cases of known parental balanced translocation or when hygroma is detected by ultrasonography.     

A pregnancy with discordant fetal and placental chromosome 18 aneuploidies revealed by invasive and noninvasive prenatal diagnosis

This study investigated a pregnancy where the fetus was diagnosed with monosomy 18p by invasive amniocentesis and karyotyping. Additional noninvasive prenatal diagnosis, which detects fetal chromosome abnormalities in the circulating cell-free plasma DNA originating from the placenta revealed a related 18p monosomy/18q trisomy, suggesting confined placental mosaicism. Based on recent observations of chromosomal instability in the early preimplantation embryo, this study speculates on the possible embryonic origin(s) of these related but discordant chromosome 18 aneuploidies in the placental and fetal tissues. The findings highlight the potential for both false-positive and -negative noninvasive prenatal diagnosis results in pregnancies where there is either confined placental mosaicism or placental mosaicism.The study investigated a pregnancy involving a fetus with a chromosome disease syndrome called monosomy 18p where part of the short arm of chromosome 18 was missing in the fetal tissues. Using non-invasive prenatal diagnosis which detects fetal chromosome abnormalities in the circulating cell free plasma DNA originating from the placenta, we also detected monosomy 18p as well a related chromosome 18 abnormality involving duplication of the long arm of chromosome 18. This suggested confined placental mosaicism where the constitution of the chromosomes are different between fetal and placental tissues. We speculated that these related chromosome 18 abnormalities arose during preimplantation embryo development, leading to the formation of different chromosome abnormalities observed in the placental and fetal tissues of this pregnancy. Our findings highlight the potential for both false positive and negative non-invasive prenatal diagnosis test results in pregnancies where there is confined placental mosaicism.     

The detection of aneuploidy and maternal contamination by QF-PCR in samples undergoing prenatal diagnosis for thalassemia in Southern China

Objectives

To apply a simple and low-cost approach, which would easily and accurately detect both the common chromosomal abnormalities and maternal cell contamination (MCC) when invasive prenatal testing is performed for diagnosis of thalassemia.

Study design

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 11 primer pairs for loci on each of chromosomes 13, 18 and 21 was used.

Results

A total of 387 prenatal samples were tested. Five (1.3%) samples showed MCC, including two (0.7%, 2/289) amniotic fluid samples and three (3.1%; 3/98) chorionic villi samples. Of the 379 prenatal samples without MCC, QF-PCR assays detected two (0.5%) cases of trisomy 21, which were confirmed by traditional karyotyping, and missed one case of trisomy 2 mosaicism and one case of monosomy X. The case of trisomy 2 mosaicism was later found to be limited to the placenta, and the case of monosomy X was picked up by ultrasound. There was no clinically significant case that would have been missed if QF-PCR had been used as a stand-alone test instead of karyotyping when invasive prenatal testing was performed for diagnosis of thalassaemia.

Conclusions

The QF-PCR assay could allow simultaneous detection of aneuploidy and possible MCC in the fetal material. This is especially valuable when PCR-based techniques are used in the DNA analysis for thalassaemia. This strategy may be applied to prenatal diagnosis of other recessive disorders.     

Chromosomal mosaicism in chorionic villus sampling

The observation of multiple, chromosomally distinct cell lines in chorionic villus samples is not an unusual finding and occurs in 1 per 100 samples. This frequency is ten times greater than the level of mosaicism observed in newborn surveys and, thus, must reflect phenomenon other than true fetal mosaicism. Indeed, only 23% of mosaicism detected at CVS is confirmed in the fetus (2.3 per 1,000 CVS), which is much closer to the newborn rate (1 per 1,000). This indicates that most mosaicism encountered in CVS is unrelated to the fetal karyotype and as such is an inaccurate prediction of the fetal genotype, the purpose of prenatal diagnosis. Most of the mosaicism detected in CVS is due to confined placental mosaicism. Either as a result of error-prone cell division generating an excess of abnormal cells in extraembryonic tissues or reduced selection against aneuploid cells in these tissues allowing their persistence, chorionic villi and placenta appear to show much higher levels of mosaicism than seen in fetuses. This explains the more frequent finding of multiple cell lines in CVS than in amniocentesis or liveborn individuals. The discrepancy between levels of mosaicism present in chorionic villi and fetal tissues means that most instances of mosaicism detected in CVS are not associated with a fetal abnormality and should be evaluated by further prenatal testing, i.e., amniocentesis or fetal blood sampling. Because of the frequency of chromosomal mosaicism in CVS and its attendant need for further testing, a discussion of mosaicism should be included in counseling prior to CVS. The higher frequency of discrepant results in direct CVS preparation emphasizes the prudence of delaying decision making until the results of the CVS culture have been obtained. Although the observation of mosaicism clearly complicates genetic counseling and decision making, it does not appear to be associated with an adverse fetal outcome. Whereas most of the mosaicism observed in CVS is the result of confined placental mosaicism, other types of discrepancies also occur. Maternal cell contamination occurs in about 1% of cases, but is easily evaluated by examining the direct preparation and analyzing chromosome polymorphism. The incidence of pseudomosaicism in CVS cultures is unclear but probably low. Interestingly, CVS analysis has suggested that twinning may be a more common phenomenon at conception than reported at birth and that some discrepancies may reflect the nonviability of twins with abnormal karyotypes. Chorionic villi sampling remains a viable alternative to amniocentesis for early prenatal diagnosis. An understanding of the origins of mosaicism in CVS is necessary for     

Rapid prenatal diagnosis of trisomy 21 in 5049 consecutive uncultured amniotic fluid samples by fluorescence in situ hybridisation (FISH).

OBJECTIVES: This was a retrospective study on the results of interphase fluorescence in situ hybridization (FISH), performed routinely for chromosome 21 and on ultrasonographic indications for chromosomes 13, 18, X and Y in a series of 5049 amniotic fluid samples. METHODS: Interphase FISH for chromosome 21 was performed in 5049 consecutive amniotic fluid samples for the rapid prenatal diagnosis of Down syndrome. Aneuploidy for four other chromosomes (13, 18, X and Y) was tested following ultrasonographic indications. Karyotypes from standard cytogenetic analysis were compared to the FISH results. RESULTS: Using conventional cytogenetics 3.6% (183/5049) chromosomal anomalies were detected. After exclusion of familial chromosome rearrangements, i.e. balanced autosomal reciprocal or Robertsonian translocations (30/5049) and inversions (19/5049), 2.65% chromosomal anomalies (134/5049) were diagnosed. Of this group 0.18% (9/5049) were chromosomal rearrangements not detectable by FISH and 2.47% (125/5049) were numerical chromosomal anomalies detectable by interphase FISH for chromosomes 13, 18, 21, X and Y. With routine interphase FISH for chromosome 21 and FISH on echographic indication for the other four chromosomes we detected 107/125 of these numerical chromosomal anomalies, i.e. 85.6%. All 70 cases of trisomy 21 were detected by FISH and confirmed with conventional cytogenetics (sensitivity=100%) and there were no false-positive results (specificity=100%). Maternal cell contamination of amniotic fluid samples occurred in 1.27% (64/5049) of samples; 0.26% (13/5049) of these samples were uninformative by FISH due to maternal cell contamination (12/5049) or absence of nuclei in one sample (1/5049). CONCLUSION: In this group of 5049 samples we found that FISH is a reliable technique for the rapid prenatal diagnosis of trisomy 21. The number of uninformative cases due to maternal cell contamination was low. The strategy to perform FISH for chromosome 21 in all samples and only on ultrasonographic indication for the four other chromosomes (13, 18, X and Y) followed by standard cytogenetics is effective.     

Prenatal diagnosis of Pallister-Killian syndrome in pregnancy with normal CVS result and abnormal ultrasound findings in the second trimester

Objective

To highlight importance of detailed ultrasound examination in fetuses with known normal karyotype (and micro-array result) from CVS. In case of markedly abnormal ultrasound result repeated karyotyping by amniocentesis should be considered. Sample should be analyzed by routine cytogenetic techniques, however also micro-array and targeted FISH should be added in order to achieve most accurate diagnosis.

Defining the efficiency of fluorescence in situ hybridization on uncultured amniocytes on a retrospective cohort of 27407 prenatal diagnoses

Rapid prenatal detection of selected numerical chromosomal abnormalities by using fluorescence in situ hybridization (FISH) on uncultured amniotic fluid samples was described six years ago. It allows a very rapid identification of selected aneuploidies. We have indexed the results of our 27407 fetal karyotypes obtained by conventional cytogenetics during the last five years, noting the type of chromosomal abnormality and the reasons for prenatal diagnosis. We have also indexed the chromosomal abnormality regarding the prognosis of the chromosomal aberations to evaluate the real impact of a non-diagnosis. Within the population of bad prognosis abnormalities, the percentage of abnormalities with bad prognosis detectable by FISH is 94.6% for advanced maternal age, 85.3% for ultrasonographic anomalies and 86.4% for positive maternal screening. The use of FISH alone on our cohort is not a suitable method to diagnose the chromosomal abnormalities.     

Issues arising from the prenatal diagnosis of some rare trisomy mosaics--the importance of cryptic fetal mosaicism

OBJECTIVES: To add to the knowledge of fetal mosaicism, confined placental mosaicism (CPM), and uniparental disomy (UPD), in rare trisomies detected at prenatal diagnosis. METHODS: The origin of rare trisomy mosaics, mostly (8/11) seen in amniocytes, was examined in 11 cases by follow-up karyotyping and the study of microsatellite inheritance. RESULTS: Of the rare trisomies presented, three were mosaic trisomy 16 (two of which were CPM), and the remainder comprised single cases of mosaic trisomies of 8, 9, 10, 11, 12, 14, 5 and 15--the last two being CPM. Cases varied in parental derivation and meiotic versus post-zygotic origin but no case involved UPD. There was evidence for cryptic fetal mosaicism in three cases (5, 7, 11)--involving chromosomes 11, 14 and 16. CONCLUSIONS: These cases contribute further data to phenotypes associated with rare trisomies and the relative influences on the phenotype of CPM, UPD and fetal mosaicism. From sparse published data, we estimate that approximately 10% of apparent CPM cases for a rare trisomy (i.e. aneuploid CVS, normal amniocytes) may actually be cryptic fetal mosaics undetected in cultured amniocytes. In many cases, this cryptic mosaicism may be of limited clinical significance, but in others, the associated phenotypic effects may be obvious. There is no general approach to resolve this issue; the finding of even a few similar aneuploid cells in different amniocyte culture vessels may be clinically significant. It may be useful to study such an amniocyte culture with FISH with the relevant centromeric probe. Careful follow-up is recommended, particularly for infants where apparent correction of autosomal trisomy has occurred.