Sex chromosome trisomies in Europe: prevalence, prenatal detection and outcome of pregnancy

This study aims to assess prevalence and pregnancy outcome for sex chromosome trisomies (SCTs) diagnosed prenatally or in the first year of life. Data held by the European Surveillance of Congenital Anomalies (EUROCAT) database on SCT cases delivered 2000–2005 from 19 population-based registries in 11 European countries covering 2.5 million births were analysed. Cases included were livebirths diagnosed to 1 year of age, fetal deaths from 20 weeks gestation and terminations of pregnancy for fetal anomaly (TOPFA). In all, 465 cases of SCT were diagnosed between 2000 and 2005, a prevalence of 1.88 per 10,000 births (95% CI 1.71–2.06). Prevalence of XXX, XXY and XYY were 0.54 (95% CI 0.46–0.64), 1.04 (95% CI 0.92–1.17) and 0.30 (95% CI 0.24–0.38), respectively. In all, 415 (89%) were prenatally diagnosed and 151 (36%) of these resulted in TOPFA. There was wide country variation in prevalence (0.19–5.36 per 1000), proportion prenatally diagnosed (50–100%) and proportion of prenatally diagnosed resulting in TOPFA (13–67%). Prevalence of prenatally diagnosed cases was higher in countries with high prenatal detection rates of Down syndrome. The EUROCAT prevalence rate for SCTs diagnosed prenatally or up to 1 year of age represents 12% of the prevalence expected from cytogenetic studies of newborn babies, as the majority of cases are never diagnosed or are diagnosed later in life. There is a wide variation between European countries in prevalence, prenatal detection and TOPFA proportions, related to differences in screening policies as well as organizational and cultural factors.     

Epidemiology of orofacial clefts in a Danish county over 35 years – Before and after implementation of a prenatal screening programme for congenital anomalies

In 2004 the Danish National Board of Health changed its screening recommendations. Since 2005 a first trimester screening for Down syndrome and a prenatal ultrasound screening for congenital anomalies in the second trimester of pregnancy has been offered to all pregnant women.The aim of this study was to describe the prevalence of cleft lip with or without cleft palate and cleft palate in a Danish area and to describe associated anomalies and the development in prenatal diagnosis over time. The study was based on data from the EUROCAT Registry for Funen County. The registry is based on multiple data sources and includes information about live births, fetal deaths with a gestational age >20 weeks and terminations of pregnancy after prenatal diagnosis of severe fetal anomaly. The study included all fetuses/infants out of a population of 182,907 births diagnosed with orofacial clefts born between 1980 and 2014. There were 271 cases diagnosed with cleft lip with or without cleft palate and 127 cases diagnosed with cleft palate, giving a prevalence of 14.8 per 10,000 births for cleft lip with or without cleft palate and 6.9 per 10,000 births for cleft palate. There were no significant changes in prevalence over time for the two anomalies, calculated with and without inclusion of genetic and chromosomal cases. Overall 66 cases were diagnosed prenatally (17% of total). For isolated cleft lip with or without cleft palate none of the 157 cases born before 2005 were diagnosed prenatally compared to 34 of 58 cases (59%) born in 2005–2014 (p?<?0.01). The proportion of liveborn infants with multiple congenital anomalies also changed after 2005 with 15% (39/266) of all liveborn infants with orofacial clefts born 1980–2004 having multiple anomalies compared to 7% (7/96) in 2005–2014 (p?<?0.05).The implementation of the new screening programme in 2005 has given a major change in prenatal detection rate and reduced the proportion of liveborn infants with orofacial clefts classified as multiple congenital anomaly cases. The prevalence of cleft lip with or without cleft palate was higher than reported from many other countries.     

Frequencies of fetal chromosomal abnormalities at prenatal diagnosis: 10 years experiences in a single institution.

We present frequencies of fetal chromosomal abnormalities in 4,907 prenatal cytogenetic examinations at Samsung Cheil Hospital from 1988 to 1997 for 10 yr duration. Prenatal karyotypes were undertaken in 3,913 amniotic fluid samples, 800 chorionic villi samples, and 194 percutaneous umbilical blood samples. The frequency of fetal abnormal karyotypes was 3.1% (150 cases). Numerical chromosome abnormalities were 87 cases (1.8%) and structural aberrations of chromosomes were 63 cases (1.3%). In the numerical chromosomal abnormalities, the frequency of trisomy 21 was by far the highest (36 cases), followed by trisomy 18 in 22 cases and sex chromosome aneuploidies in 19 cases. In the structural chromosomal aberrations, 5 cases had the inversions in chromosome 2, 7, 17, and Y. Chromosomal deletions in 6 cases and additions in 4 cases were analysed. Of the remaining 47 translocation in abnormal fetuses, reciprocal translocation was in 26 cases and Robertsonian translocation in 21 cases. Among them, 41 cases were balanced translocation and 6 were unbalanced. Thirty five cases of translocation were inherited from one of the parents. Four had de novo chromosome rearrangements, and 8 cases were unknown.     

孕中晚期21三体产前诊断的结果分析

目的通过孕中晚期21三体、18三体产前诊断的结果分析,评价孕中晚期产前诊断的价值。方法对怀孕16～29周符合产前诊断条件的孕妇经知情同意后,在B超介导下对孕16-24周孕妇行羊膜腔穿刺,抽取羊水;孕25-29周孕妇行胎儿脐静脉穿刺,抽取脐带血,进行细胞培养,染色体核型分析。结果在2689例产前诊断病例中发现异常核型149例,异常率为5.54%。常染色体结构异常-倒位核型43例、平衡易位18例、罗氏易位8例,常染色体非整倍体数量异常（21三体、18三体、13三体）48例,性染色体数量异常15例,性染色体结构异常12例,其它核型异常5例。常染色体非整倍体数量异常（21三体、18三体、13三体）占发现异常核型的32.2%（48/149）,为主要异常核型。结论羊水细胞、脐带血染色体核型分析是目前产前诊断21三体、18三体、13三体染色体异常胎儿必不可少的检查方法,对于预防缺陷儿出生,提高人口素质,优生优育具有十分重要的意义。     

连云港地区1234例羊水细胞染色体核型分析

目的分析连云港地区1234例孕中期羊水细胞染色体核型结果,探讨染色体异常核型在各产前诊断指征下发生的频率、类型及其之间的关系。方法根据产前诊断的不同指征,将染色体核型结果分组,分析染色体异常核型的检出率及分布。结果 1234例羊水细胞染色体核型中,母血清学产前筛查高风险900例（3.11%）;高龄（≥35岁）235例（2.13%）;超声提示胎儿异常62例（11.29%）;不良孕史24例（4.17%）;无创产前DNA检测提示异常7例（85.71%）,共检出异常核型48例（3.89%）。异常核型中染色体易位6例,5例遗传自亲代,1例为新发突变;染色体倒位6例,均遗传自亲代;性染色体异常7例,21三体15例,18三体4例,13三体1例,三倍体1例。结论羊水细胞染色体核型分析是临床产前诊断的经典方法之一。超声检查提示异常以及高龄孕妇应注意胎儿染色体异常的可能性。对于无创产前DNA检测的结果要进行羊水细胞染色体核型分析的验证。     

Prenatal detection of rare chromosomal autosomal abnormalities in Europe

The aim of the present study was to evaluate the prenatal detection of rare chromosomal autosomal abnormalities by ultrasound (US) examination. Data were obtained from 19 congenital malformation registries from 11 European countries, between 01/07/96 and 31/12/98. A total of 664,340 births were covered and 7,758 cases with congenital malformations were recorded. Rare autosomal abnormalities were diagnosed in 114 cases (6.6%) from a total of 1,738 chromosome abnormalities. There were a wide variety of autosomal abnormalities: the most common were deletions (33 cases), duplications (32 cases), trisomies of chromosomes 8, 9, 10, 14, 15, and 16 (23 cases), and unbalanced rearrangements (19 cases). Out of these cases, 45.6% were detected prenatally by US examination due to the presence of congenital anomaly. As for the types of chromosomal anomaly, unbalanced rearrangements and deletions were the most frequently detected by US. A high percentage of cases with balanced rearrangements were associated with severe congenital anomalies. The most frequent congenital anomalies detected by US were cystic hygroma (20.6%), central nervous system defects (17.6%), cardiac defects (13.2%), and diaphragm defects (10.3%). This large series offers useful information about prenatal diagnosis by US of congenital defects associated with rare autosomal abnormalities and it provides a valuable knowledge about outcome. Fetal anomalies detected by US that were associated with rare autosomal abnormalities were significantly more frequent than those associated with common chromosomal abnormalities (45.6 vs. 34.7%). This study indicates the need to increase the detection of congenital anomalies by US.     

胎儿结构畸形、微小畸形与染色体异常的相关性研究

目的通过对不同类型和数量的胎儿结构畸形、微小畸形与染色体异常的关系性研究,从而对具有上述病变的胎儿的遗传咨询和染色体产前诊断做一个更好的指引。方法收集2004年1月至2005年12月因发现胎儿结构畸形和微小畸形于孕中晚期进行脐带穿刺术及染色体检查病例120例。统计不同的结构畸形、微小畸形的染色体异常核型的检出率、检出类型。并对所有病例进行术后或出生后随访。结果脐带穿刺术和脐血染色体培养成功率为100%,检出异常核型13例(10.8%)。其中18三体异常核型6例,21三体2例,13三体1例,45,XO(Turner综合征)1例,衍生染色体2例,嵌合体1例。多发畸形染色体异常发生率为40%(8/20);单发畸形染色体异常发生率为7.3%(3/41);单独存在的胎儿超声软指标染色体异常发生率为2.1%(1/47);多个超声软指标染色体异常发生率为8.3%(1/12)。结论胎儿结构畸形与非整倍体染色体病关系密切,而单独存在的超声软指标发生染色体异常的机率较低,但当出现2个以上软指标时发生染色体异常的几率将增加。我们应根据结构异常的种类和数量,给予孕妇不同的产前咨询意见和提供必要的侵入性检查。     

Prevalence and associated factors for agenesis of corpus callosum in Emilia Romagna (1981–2015)

Agenesis and hypoplasia of the corpus callosum (ACC and HCC) are heterogeneous group with a large variation in published prevalence based on few population based studies. The aim of this work is to describe prevalence, associated factors and other malformations present in cases with either agenesis or hypoplasia of the corpus callosum, using a population-based database of all malformations diagnosed in Emilia-Romagna, Italy, (the Emilia-Romagna Registry on Congenital Malformations, IMER).This registry links and integrates hospital discharge records, birth certificates with cases reported by referral clinicians to identify all structural malformations diagnosed within one year of life regarding live birth, fetal death or termination of pregnancy due to fetal malformations (TOPFA). During the study period (1981–2015) the number of cases with ACC or HCC was 255, in a reference population of 1,023,784 live births, giving an overall prevalence of 2.49 per 10,000 (1.47 per 10,000 only live birth). After 1996, with the inclusion of TOPFA in IMER registry, the overall prevalence rate increase significantly from 1.42 to 3.03 cases per 10,000 birth (p-value<0.001). Prenatal diagnosis was made in 192 cases (75.3%), at a median gestational age of 20.7 [IQR: 19.71–22.71]. Termination of pregnancy occurred in 105 of the 255 cases (41,2%). Where a prenatal diagnosis was available, 55% of cases ended in TOPFA (105/192), with higher prevalence of cases associated to central nervous system malformations and multiple birth defects, and median gestational age at diagnosis significantly less than in live birth cases (20.3 vs 29 weeks). Agenesis/hypoplasia ratio was 5.7 (217/38). The most frequently associated malformations were musculoskeletal. Trisomies were the most frequent chromosomal anomalies, in particularly trisomy18 and 13 (respectively 9/32 and 4/32 cases). Our study showed an increased risk for male infants (RR of 1.68, RR 95% CI 1.19–2.37). No differences were detected analyzing maternal age and ethnicity, and the increased risk associated to preterm birth disappeared when compared with other malformed infants.This is one of the few population based studies dealing with prevalence of agenesis and hypoplasia of corpus callosum. Prevalence is still debated, but this study adds comprehensive data, in particular inclusion of TOPFA cases. Early prenatal diagnosis, not always possible, could be crucial for decision making regarding continuation of pregnancy.     

Population-based impact of noninvasive prenatal screening on screening and diagnostic testing for fetal aneuploidy

PurposeTo assess the population-wide impact of noninvasive prenatal screening (NIPS) on combined first-trimester screening (CFTS), early ultrasound (11–13 weeks), and invasive prenatal diagnosis in a state with over 73,000 births per year.MethodsAnalysis of population-based data from 2000 to 2015 including (i) invasive prenatal tests, (ii) CFTS uptake, and (iii) total births. Utilization of early ultrasound was analyzed before and after NIPS (2010–2015).ResultsInvasive testing decreased significantly by 39.6% from 2012 to 2015 despite steady births. More than half of all confirmed cases of trisomy 21 were ascertained by NIPS in 2015, despite NIPS comprising only 11.7% of total indications for invasive testing. CFTS uptake declined significantly from 77.5% in 2013 to 68.1% in 2015, but 11- to 13-week ultrasounds did not. In 2015, ultrasound abnormality replaced CFTS as the most common indication for invasive testing and chromosomal microarray was performed for 85.3% of all prenatal karyotypes.ConclusionPrenatal testing is now unequivocally in the genomic era. NIPS is now the screening test that precedes the majority of confirmed diagnoses of trisomy 21. The contributions of NIPS, early ultrasound, and chromosome microarray have led to unprecedented detection rates of major chromosome abnormalities, now found in 20% of all invasive tests.     

Pregnancy outcome and prenatal diagnosis of sex chromosome abnormalities in Hawaii, 1986-1999

Sex chromosome abnormalities such as Turner syndrome, Klinefelter syndrome, triple X syndrome, and 47,XYY can be prenatally diagnosed and electively terminated. This investigation examined the pattern of pregnancy outcome of prenatally and postnatally diagnosed sex chromosome abnormalities in Hawaii during 1986-1999 and calculated prenatal diagnosis and subsequent elective termination rates for various factors. Data were obtained from a statewide population-based birth defects registry. The study included 205 detected sex chromosome abnormality cases of which 93 (45%) were live births, 18 (9%) late fetal deaths, 37 (18%) early fetal deaths, and 57 (28%) elective terminations. Pregnancy outcome distribution varied by type of sex chromosome abnormality. Prenatal diagnosis was reported for 132 (64%) of the cases, of which 46 (35%) were subsequently electively terminated. Eleven cases were elective terminations where the sex chromosome abnormality was diagnosed after delivery. Elective termination rates subsequent to prenatal diagnosis differed by sex chromosome abnormality, being highest for 45,X (54%), followed by 47,XXY (46%), 47,XYY (29%), and 47,XXX (17%). Although prenatal diagnosis rates increased significantly over the time period (P = 0.006), the subsequent elective termination rate declined slightly, albeit the trend was not statistically significant (P = 0.440). The prenatal diagnosis rate was highest for the 35-39-year maternal age group, although this age group did not have subsequent elective termination rates higher than other maternal age groups. Pregnancy outcome distribution and prenatal diagnosis and subsequent elective termination of sex chromosome abnormalities appeared to depend on the type of sex chromosome abnormality, year of delivery, and maternal age.     

青岛地区1206例孕妇羊水染色体核型分析

目的评价羊水细胞的染色体核型分析对妊娠中期的高危孕妇进行产前诊断的意义。方法对妊娠19～23周的高危孕妇进行羊膜腔穿刺术并进行细胞培养染色体核型分析。结果羊水细胞培养成功率99.9%,检出染色体异常47例,包括21-三体23例,18-三体2例,性染色体异常5例,22-三体1例以及其他染色体结构异常16例。结论孕妇羊水细胞染色体核型检查,能安全有效的对胎儿染色体异常进行产前诊断,对于减少具有染色体病患儿的出生具有重要的指导意义。     

Twenty-year trends in the prevalence of Down syndrome and other trisomies in Europe: impact of maternal age and prenatal screening

This study examines trends and geographical differences in total and live birth prevalence of trisomies 21, 18 and 13 with regard to increasing maternal age and prenatal diagnosis in Europe. Twenty-one population-based EUROCAT registries covering 6.1 million births between 1990 and 2009 participated. Trisomy cases included live births, fetal deaths from 20 weeks gestational age and terminations of pregnancy for fetal anomaly. We present correction to 20 weeks gestational age (ie, correcting early terminations for the probability of fetal survival to 20 weeks) to allow for artefactual screening-related differences in total prevalence. Poisson regression was used. The proportion of births in the population to mothers aged 35+ years in the participating registries increased from 13% in 1990 to 19% in 2009. Total prevalence per 10 000 births was 22.0 (95% CI 21.7–22.4) for trisomy 21, 5.0 (95% CI 4.8–5.1) for trisomy 18 and 2.0 (95% CI 1.9–2.2) for trisomy 13; live birth prevalence was 11.2 (95% CI 10.9–11.5) for trisomy 21, 1.04 (95% CI 0.96–1.12) for trisomy 18 and 0.48 (95% CI 0.43–0.54) for trisomy 13. There was an increase in total and total corrected prevalence of all three trisomies over time, mainly explained by increasing maternal age. Live birth prevalence remained stable over time. For trisomy 21, there was a three-fold variation in live birth prevalence between countries. The rise in maternal age has led to an increase in the number of trisomy-affected pregnancies in Europe. Live birth prevalence has remained stable overall. Differences in prenatal screening and termination between countries lead to wide variation in live birth prevalence.     

Natural outcome of trisomy 13, trisomy 18, and triploidy after prenatal diagnosis

Trisomy 13, trisomy 18, and triploidy belong to the chromosomal abnormalities which are compatible with life, but which are also associated with a high rate of spontaneous abortion, intrauterine death, and a short life span. This study was conducted to analyze natural outcome after prenatal diagnosis of these disorders. Between January 1, 1999 and December 31, 2009, we investigated all amniocenteses and chorionic villus biopsies carried out at our department. All cases with fetal diagnosis of triploidy, trisomy 13, and 18 were analyzed, with a focus on cases with natural outcome. Overall, 83 (78%) cases of pregnancy termination and 24 (22%) patients with natural outcome (NO) were identified. The NO group included 15 cases of trisomy 18, six cases of triploidy, and three cases of trisomy 13. No case of triploidy was born alive. The live birth rate was 13% for trisomy 18 and 33% for trisomy 13. The three live-born infants with trisomy 13 and 18 died early after a maximum of 87 hr postpartum. Our data are consistent with the literature concerning outcome of triploidy, with none or only a few live births. Analyzes of trisomy 13 and 18 indicate a very short postnatal life span. Different study designs and diverse treatment strategies greatly affect the fetal and neonatal outcome of fetuses with triploidy, trisomy 13, and 18. More studies analyzing natural outcome after prenatal diagnosis of these chromosomal abnormalities are needed. Non-termination of these pregnancies remains an option, and specialists advising parents need accurate data for counseling.     

羊水细胞学检查在产前诊断中的应用

目的：分析产前诊断的高危孕妇羊水细胞染色体核型,了解孕中期异常核型出现的频率,类型及与各种产前诊断指征之间的关系。方法：130例有产前论断孕妇（2例为双胎妊娠）在妊娠17－27周时行羊膜腔穿刺术,抽羊水行羊水细胞培养查染色体核型。结果：羊水细胞培养成功并进行核型分析的为126例,成功率为95．4％;妊17－20周与妊20－27周的羊水培养成功率未见显著差异,分别95．9％（71／74）,94．8％（55／58）,P＞0．05;发现异常核型10例,异常检出率为7．8％（10／126）;三体为主要的染色体异常,占异常核型的40％（4／10）,其中21三体占30％（3／10）,性染色体数目异常及平衡易位各1例,4例INV9;畸胎为指征的异常核型检出率高达33．3％（2／6）;发现1例单卵双胎妊娠两胎均为21三体儿;高龄为指征占成功产前诊断的46．3％（60／126）,检出异常核型3例,检出率5％（3／60）。结论：在有产前诊断指征的孕妇中,胎儿染色体异常核型的发生率为7．8％,三本仍是妊娠中期主要的异常核型,结合B超筛查及定位的羊膜腔穿刺术在产前诊断仍占有不可代替的重要作用。     

母血清筛查21三体、18三体阳性病例的产前诊断

目的探讨孕中期母血清筛查21-三体，18-三体阳性病例的染色体异常情况。方法AFP和Free-heG13用美国PE公司的时间分辨免疫荧光分析系统测定，风险值计算21-三体以1／270，18-三体以1／350为切割值。阳性病例进行羊膜腔穿刺羊水细胞培养。结果在54580例产前筛中有2615例为21-三体或18-三体阳性病例，占总筛查人数的4．79％。其中对1161例阳性病例进行了染色体分析（占总阳性数的44．4％）。结果发现29例异常核型，其中21-三体14例，18-三体5例，性染色体异常3例，其他异常核型7例，异常发生率2．49％。结论母血清产前筛查结合羊水诊断能够有效的避免胎儿染色体异常的发生。     

佛山地区产前筛查与产前诊断分析研究

目的佛山地区产前筛查与产前诊断分析研究。方法选择自2006年1月～2008年12月来本院进行产前检查的孕妇共41 656例,其中有2 9101例自愿行血清学筛查,孕周为15～25周,年龄21～42岁,平均年龄为25.73岁。有41 333例行超声筛查,孕周11～36周。对唐氏筛查及B超筛查结果为高风险的孕妇进行遗传咨询,建议进行产前诊断确诊。产前诊断的方法采用羊膜腔穿刺羊水细胞培养或经腹脐静脉穿刺脐血细胞培养,染色体检查采用G带染色。结果在血清筛查2 9101例孕妇中,筛查出高风险3227例,阳性率为11.1%。其中21三体高风险1287例,占4.4%;18三体高风险423例,占1.45%。在血清筛查高风险的3227例孕妇中,接受产前诊断者1065例,占33%（1065/3227）。染色体核型异常者100例,占12.49%,占高风险孕妇的4.12%（100/3227）。其中21三体19例,18三体2例,检出率为1.97%（21/1065）,占染色体核型异常的21%（21/100）。有41 333例行超声筛查,超声检查筛查出高风险851例,阳性率为2.06%。行产前诊断206例,染色体异常45例,占21.84%（45/206）,其中检查出21三体5例,18三体8例,13三体1例,占染色体异常的31.11%（14/45）。结论将孕妇年龄、血清学检测和超声筛查作为产前筛查唐氏综合征的方法,明显提高了筛查阳性率,通过产前筛查将高风险的人群筛查出来作产前诊断,减少了缺陷儿出生。     

评价羊水染色体检测在产前诊断中的作用

目的评价羊水细胞染色体检测在产前诊断中的作用。方法对妊娠16∽24w的孕妇939例进行羊膜腔穿刺术,对羊水细胞染色体分析。结果检测出染色体异常共54例,其中21-三体13例,18-三体1例,13-三体1例,性染色体异常9例,平衡易位14例,其他染色体结构异常16例。结论羊水染色体检测可安全、有效的检测胎儿染色体异常,具有重要意义,值得进一步推广。     

细菌人工染色体微珠联合染色体核型分析在产前诊断中的价值研究

目的探讨细菌人工染色体微珠(BACs-on-Beads,BoBs)联合染色体核型分析在产前诊断中的价值。方法2016年6月至2019年1月在本院接受侵入性产前诊断的2500例单胎妊娠孕妇作为研究对象,均采集羊水。同时进行羊水细胞的BoBs检测和染色体G显带核型分析。结果BoBs技术共检出93例胎儿染色体异常,检出率为3.72%,其中染色体数目异常78例(4例13号染色体三体,19例18号染色体三体,34例21号染色体三体,9例XXX,6例XXY,6例XYY)、染色体结构异常9例(6例未被核型分析检出)、嵌合型染色体6例。在6例染色体结构异常的胎儿中,DiGeorge综合征和Williams-Beuren综合征各1例,其余4例为染色体微缺失/微重复综合征。核型分析对胎儿异常的检出率为4.56%(114/2500),核型分析对染色体数目异常的检出率与BoBs检测相同。核型分析额外检出21例染色体结构异常和6例嵌合型染色体。结论染色体核型分析联合BoBs技术发挥了细胞遗传学和分子遗传学的技术优势,极大提高了染色体异常的检出率,值得在临床应用和推广。     

Using population-based data to predict the impact of introducing noninvasive prenatal diagnosis for Down syndrome

PurposeTo compare the number and types of chromosome abnormalities prenatally diagnosed and the number of invasive procedures between current prenatal testing pathways and a pathway where noninvasive prenatal diagnosis for Down syndrome replaces Down syndrome screening tests.MethodsNumbers and types of chromosome abnormalities for each referral category were extracted from prenatal diagnostic testing reports routinely collected in Victoria, Australia, in 2006 and 2007. These data were then applied to the proposed implementation strategy.ResultsIf noninvasive prenatal diagnosis for Down syndrome had replaced Down syndrome screening tests in 2006 and 2007, in Victoria, there would have been 25 (7%) additional Down syndrome diagnosed, 6896 (84%) fewer invasive procedures, and 231 (56%) non-Down syndrome chromosome abnormalities no longer detected. These include trisomy 13, trisomy 18, sex chromosome abnormalities, balanced and unbalanced rearrangements, polyploidy, and mosaic results.ConclusionsThe potential loss of information about chromosome abnormalities other than Down syndrome with noninvasive prenatal diagnosis compared with full karyotyping with traditional prenatal diagnosis should be considered when planning for the implementation of new technologies.     

妊娠中、晚期300例胎儿脐血染色体核型分析

目的 分析妊娠中、晚期胎儿脐血染色体核型,了解该时期异常核型出现的频率、类型及与各种产前诊断指征的关系。方法 ３００例有产前诊断指征的孕妇,在妊娠１８～３８孕周时穿刺胎儿脐带血管,帛脐箅查染色体核型。结果 发现异常核型２３例（７．７％）,其中２１三体占３９．１％（８／１２６）,Ｐ＝０．７７。三体为主要的染色体异常,占异常核型的６０．９％（１４／２３）。其中２１三体占３９．１％（９／２３）,平衡易位