Trisomies 13 and 18: population prevalences, characteristics, and prenatal diagnosis, metropolitan Atlanta, 1994-2003

In recent years, prenatal diagnosis and elective pregnancy termination have affected the reported birth prevalence of trisomies 13 and 18. We examined the prevalence and characteristics of these conditions using 1994-2003 data from a population-based surveillance system, the Metropolitan Atlanta Congenital Defects Program. Including fetal deaths and elective terminations increased the number of affected pregnancies by 58.7% for trisomy 13 and 72.2% for trisomy 18. Prenatal cytogenetic testing was reported in 70.8% of trisomy 13 cases and 76.1% of trisomy 18 cases. Among those with prenatal cytogenetic tests, 60.8% of trisomy 13 and 59.7% of trisomy 18 cases were electively terminated. Compared with non-Hispanic whites, non-Hispanic black race was associated with a decreased frequency of prenatal cytogenetic testing for both trisomy 13 and trisomy 18 (OR 0.24, 95% CI: 0.08-0.78 and OR 0.32, 95% CI: 0.14-0.69, respectively). The reported rates of prenatal cytogenetic testing remained stable throughout the period. As expected, maternal age > or =35 years was a risk factor for both conditions. However, while 67.1% (n = 55) of the trisomy 18 case mothers were > or =35 years, only 46.9% (n = 15) of the trisomy 13 case mothers were > or =35 years. Among live-born infants, the sex ratio among trisomy 18 infants showed an increased proportion of females: 60.4% female versus 39.6% male. However, the proportion was 48.3% female and 51.7% male among fetuses that were electively terminated in the second trimester. Inclusion of pregnancies that are prenatally diagnosed is critical for accurate surveillance and population-based analyses of these conditions.     

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.     

Rare chromosome abnormalities, prevalence and prenatal diagnosis rates from population-based congenital anomaly registers in Europe

The aim of this study is to quantify the prevalence and types of rare chromosome abnormalities (RCAs) in Europe for 2000-2006 inclusive, and to describe prenatal diagnosis rates and pregnancy outcome. Data held by the European Surveillance of Congenital Anomalies database were analysed on all the cases from 16 population-based registries in 11 European countries diagnosed prenatally or before 1 year of age, and delivered between 2000 and 2006. Cases were all unbalanced chromosome abnormalities and included live births, fetal deaths from 20 weeks gestation and terminations of pregnancy for fetal anomaly. There were 10,323 cases with a chromosome abnormality, giving a total birth prevalence rate of 43.8/10,000 births. Of these, 7335 cases had trisomy 21,18 or 13, giving individual prevalence rates of 23.0, 5.9 and 2.3/10,000 births, respectively (53, 13 and 5% of all reported chromosome errors, respectively). In all, 473 cases (5%) had a sex chromosome trisomy, and 778 (8%) had 45,X, giving prevalence rates of 2.0 and 3.3/10,000 births, respectively. There were 1,737 RCA cases (17%), giving a prevalence of 7.4/10,000 births. These included triploidy, other trisomies, marker chromosomes, unbalanced translocations, deletions and duplications. There was a wide variation between the registers in both the overall prenatal diagnosis rate of RCA, an average of 65% (range 5-92%) and the prevalence of RCA (range 2.4-12.9/10,000 births). In all, 49% were liveborn. The data provide the prevalence of families currently requiring specialised genetic counselling services in the perinatal period for these conditions and, for some, long-term care.     

Age-specific incidences of chromosome abnormalities at the second trimester amniocentesis for Japanese mothers aged 35 and older: collaborative study of 5484 cases

The aim of this study was to calculate the expected incidences of chromosome abnormalities found at amniocentesis in Japanese women aged 35 and older. From four clinics in Japan, we gathered genetic amniocentesis data on 5484 pregnant women at risk only due to their advanced age, 35 years and older. We analyzed the data using the logistic regression model. Of the 5484 fetuses, 117 (2.1%) were diagnosed with a chromosome abnormality. The abnormal karyotypes included 42 cases of trisomy 21; 13 of trisomy 18; 7 of trisomy 13; 10 of 47,XXY; 4 of 47,XXX; 1 of 47,XYY; 27 with various structural aberrations; and 13 with various types of mosaicism. The incidences of trisomy 21, lethal autosomal aneuploidies (trisomy 18 and trisomy 13), and sex-chromosome abnormalities (XXY, XXX, XYY) increased with maternal age. Parameters of the regression equations with their standard errors were calculated and the expected incidences of chromosome abnormalities at each maternal age were derived. The expected incidences of chromosome abnormalities obtained in this study are the first data published for Japan and will be useful for the counseling of pregnant women. The incidence of trisomy 21 is not different from the rates published previously for Western countries. The incidences of chromosome abnormalities are not affected by race or by geographic factors. Received: July 23, 1997 / Accepted: December 1, 1997     

Epidemiology of triploidy in a population-based birth defects registry,Hawaii, 1986-1999

Triploidy is a highly lethal chromosomal abnormality with few fetuses surviving to term. Triploidy has not been extensively studied using data from a population-based birth defect registry. This investigation examined the epidemiology of triploidy using data from the Hawaii Birth Defects Program (HBDP) and compared its findings with the literature. Of the 38 identified cases of triploidy delivered in Hawaii during 1986-1999, 31 (82%) were early fetal deaths, 3 (8%) late fetal deaths, and 4 (11%) elective terminations. The distribution of cases by sex chromosome combination was 15 (39%) XXX, 22 (58%) XXY, and 1 (3%) XYY. Triploidy was prenatally diagnosed in eight (21%) of the cases, of which four were electively terminated, two resulted in early fetal death, and two resulted in late fetal death. The detected triploidy prevalence in 1993-1999 was higher than the prevalence in 1986-1992, although the difference was not statistically significant (rate ratio (RR) 1.20, 95% confidence interval (CI) 0.73-1.86). The detected triploidy prevalence for maternal age of 35 years or greater was significantly higher than the prevalence for maternal age less than 35 years (RR 4.07, 95% CI 2.22-6.83). In spite of under detection of cases, many aspects of the epidemiology of triploidy identified in a population-based birth defects registry were consistent with that reported in the literature.     

Confirmation of prenatal diagnosis of sex chromosome mosaicism

Prenatal diagnosis of mosaicism causes problems in interpretation and in genetic counselling. Part of the difficulty with any prenatal diagnosis of mosaicism is interpretation of results without knowing the exact origin, embryonic or extraembryonic, of the abnormal cell line. To confuse the issue in cases of prenatal diagnosis of 45,X/46,XY mosaicism is the recent demonstration that a diagnosis of 45,X/46,XY made prenatally is not necessarily associated with the same phenotype as when diagnosed postnatally. We present two cases of prenatal diagnosis of sex chromosome mosaicism (45,X/46,XY and 45,X/47,XYY). Posttermination examination of the phenotypically normal male fetuses and their placentas established that the placenta was the most likely source of the 45,X cell line. An approach to confirming the prenatal diagnosis of sex chromosome mosaicism and establishing its origin utilizing detailed cytogenetic examination of both fetus and placenta is suggested.     

荧光原位杂交技术在遗传病诊断中的应用

目的探讨荧光原位杂交(fluorescenceinsituhybridization,FISH)技术在遗传病和产前诊断中的应用价值。方法应用着丝粒探针、特异性序列探针及染色体涂染探针等对36例常规核型分析疑有染色体异常患者的外周血和45例进行产前诊断的孕妇羊水间期细胞或中期分裂相进行FISH检测。结果检出的染色体异常类型有45,X、45,X/46,XX、45,X/46,Xr(X)、46,X,i(Xq)、47,XXY、46,XX,t(4;7)、47,XYY、47,XXX、47,XXY,inv(7)、46,XY,inv(7)、47,XX, 21,同时产前诊断出两例异常胎儿,分别是47,XX, 18和46,XY,der(15)t(Y;15)。结论FISH技术可以准确、快速地诊断各种染色体异常,是传统细胞遗传学的必要补充,可广泛用于遗传病诊断及产前诊断。     

Maternal serum alpha-fetoprotein screening and fetal chromosome anomalies: is lowering maternal age for amniocentesis preferable?

We have compared the cytogenetic abnormalities diagnosed prenatally in 1,098 patients referred for amniocentesis because of low maternal serum alpha-fetoprotein (MSAFP) to those of 445 patients whose indication was elevated MSAFP and those of 361 patients who had amniocentesis for "maternal anxiety." Autosomal trisomies, sex chromosome aberrations, and various structural rearrangements were detected in all 3 groups and actually exceeded the age-related incidence estimates. The frequency of chromosome anomalies in cases studied because of "maternal anxiety" with no prior screening was similar to that in the group referred for low MSAFP (1.38 and 1.27%, respectively). A relatively higher frequency (2.02%) was detected in the group whose indication was elevated MSAFP. Maternal serum screening is designed primarily to recalculate risk figures for Down syndrome, but not for other major chromosome abnormalities. The concept of prenatal screening for chromosome aberrations must therefore be reevaluated. We think that efforts should be directed at making amniocenteses more accessible to patients who request it. "Lowering" maternal age limits to 30 would encompass a greater proportion of pregnancies at risk and would be a step toward more effective prenatal diagnosis for chromosome abnormalities.     

Maternal serum α-fetoprotein screening and fetal chromosome anomalies: Is lowering maternal age for amniocentesis preferable?

We have compared the cytogenetic abnormalities diagnosed prenatally in 1,098 patients referred for amniocentesis because of low maternal serum α-fetoprotein (MSAFP) to those of 445 patients whose indication was elevated MSAFP and those of 361 patients who had amniocentesis for “maternal anxiety.” Autosomal trisomies, sex chromosome aberrations, and various structural rearrangements were detected in all 3 groups and actually exceeded the age-related incidence estimates. The frequency of chromosome anomalies in cases studied because of “maternal anxiety” with no prior screening was similar to that in the group referred for low MSAFP (1.38 and 1.27%, respectively). A relatively higher frequency (2.02%) was detected in the group whose indication was elevated MSAFP. Maternal serum screening is designed primarily to recalculate risk figures for Down syndrome, but not for other major chromosome abnormalities. The concept of prenatal screening for chromosome aberrations must therefore be reevaluated. We think that efforts should be directed at making amniocenteses more accessible to patients who request it. “Lowering” maternal age limits to 30 would encompass a greater proportion of pregnancies at risk and would be a step toward more effective prenatal diagnosis for chromosome abnormalities.     

Parental decision following prenatal diagnosis of fetal chromosome abnormality

In the event of prenatal diagnosis of fetal chromosome abnormality, parents must choose between continuation and termination of the pregnancy. To determine whether parents are capable of understanding differences in severity among aneuploidy syndromes, we examined the outcome chosen for all pregnancies in which a fetal chromosome disorder was diagnosed at Northwestern Memorial Hospital between January, 1977 and June, 1986. Among amniocentesis cases, 88% with autosomal aneuploidy were terminated, but only 41% with sex chromosome abnormalities and none with de novo structural rearrangements were terminated. Among a smaller group of chorionic villus sampling cases, all with abnormal results were terminated. Similar patterns of parental behavior were noted in other prenatal diagnosis units. We conclude that parents do distinguish among, and respond specifically to, fetal chromosome disorders of differing severity, at least in the second trimester of pregnancy. However, parents appear more inclined to terminate all pregnancies with chromosome abnormalities when the diagnosis has been made in the first trimester.     

Low rates of pregnancy termination for prenatally diagnosed Klinefelter syndrome and other sex chromosome polysomies

Over the past 9 years we counseled 55 couples whose unborn child was found to carry a sex chromosome polysomy. We performed a survey of postcounseling parental decisions about continuation or termination of these pregnancies. Of the 55 embryos or fetuses, 23 had the karyotype 47,XXY, 10 had 47,XYY, and 12 had 47,XXX. In addition, there were 10 instances of true mosaicism, i.e. 47,XXY/46,XY (n = 5), 47,XYY/46,XY (n = 2), or 47,XXX/46,XX (n = 3). Mean gestational age (± standard deviation) at diagnosis was 18.3 ± 3.0 weeks. After comprehensive genetic counseling 48 (87.3%) of these pregnancies were carried to term. In seven cases (12.7%) the parents elected a pregnancy termination. Two of 31 pregnancies (6.5%) primarily ascertained at our center were aborted, whereas amongst the 24 referred cases, 5 couples (20.8%) opted for a termination. The mean gestational age of the terminated pregnancies was 19.7 weeks. The overall termination rate of 12.7% appears low in comparison with literature data. Most reports from other institutions present termination rates between 32 and 66%. The reason for the low rate of induced abortions in our study cohort is not clear. Cultural differences in parental perception of sex chromosomal polysomies may be of importance, and peculiarities of genetic counseling at our institution could also play a role. Although counseling was nondirective, we did put emphasis on providing prospective parents with information from unbiased follow-up studies of children with Klinefelter syndrome and other sex chromosome polysomies. Am. J. Med. Genet. 80:330–334, 1998. © 1998 Wiley-Liss, Inc.     

Fiscal impact of a potential legislative ban on second trimester elective terminations for prenatally diagnosed abnormalities

This study was designed to determine the fiscal impact of a theoretical legislative ban on elective terminations for prenatally diagnosed abnormalities at Hutzel Hospital/Wayne State University. A fiscal comparison was completed for patients who had second trimester elective terminations for prenatally diagnosed abnormalities versus not allowing the procedure. An eight-year database of genetics cases and hospital and physician cost estimates for performing elective terminations for prenatally diagnosed abnormalities, and published reports of the average lifetime costs per selected birth defects, were used to calculate the net cost. The estimated lifetime cost for an average cohort year of a legislative ban on elective terminations for prenatally diagnosed abnormalities was found to be at least $8.5 million for patients treated at Hutzel Hospital. Extrapolated, a similar ban on second trimester elective terminations would have a net cost of $74 million in Michigan and $2 billion annually in the United States.     

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。     

2371例孕妇产前诊断的指证及其结果分析

目的分析产前诊断指证与胎儿染色体检测结果的关系。方法 2371例有产前诊断指证的孕妇,进行羊膜腔穿刺或脐静脉穿刺术,取羊水细胞或脐血细胞培养,作胎儿染色体核型分析。结果 2371例孕妇共检出胎儿染色体异常60例,染色体异常率为2.53%,显著高于一般人群的异常率（P〈0.01）。其中孕母血清唐氏筛查阳性组和高龄孕妇组的异常率分别为1.63%（13/794）、2.32%（15/646）,产前胎儿超声异常标记组胎儿染色体异常率16.12%（15/93）,夫妇一方为染色体平衡易位携带者组的胎儿染色体异常率达71.4%（5/7）,21-三体儿检出25例,占异常率的41.67%（25/60）,其中一例连续两次诊断出21-三体儿。结论出现胎儿染色体异常率最高的指证,依次为平衡易位携带、产前超声发现胎儿异常标记、高龄孕妇、孕母血清唐氏筛查阳性。掌握好产前诊断指证,可更有价值地控制和减少出生缺陷的发生。     

Congenital heart defects associated with aneuploidy syndromes: New insights into familiar associations

The frequent occurrence of congenital heart defects (CHDs) in chromosome abnormality syndromes is well‐known, and among aneuploidy syndromes, distinctive patterns have been delineated. We update the type and frequency of CHDs in the aneuploidy syndromes involving trisomy 13, 18, 21, and 22, and in several sex chromosome abnormalities (Turner syndrome, trisomy X, Klinefelter syndrome, 47,XYY, and 48,XXYY). We also discuss the impact of noninvasive prenatal screening (mainly, cell‐free DNA analysis), critical CHD screening, and the growth of parental advocacy on their surgical management and natural history. We encourage clinicians to view the cardiac diagnosis as a “phenotype” which supplements the external dysmorphology examination. When detected prenatally, severe CHDs may influence decision‐making, and postnatally, they are often the major determinants of survival. This review should be useful to geneticists, cardiologists, neonatologists, perinatal specialists, other pediatric specialists, and general pediatricians. As patients survive (and thrive) into adulthood, internists and related adult specialists will also need to be informed about their natural history and management.     

Chromosomal factors of infertility in candidate couples for ICSI: an equal risk of constitutional aberrations in women and men

To assess the frequency of chromosomal aberrations in French candidates for intracytoplasmic sperm injection (ICSI), and to explore the existence of a female chromosomal factor in some cases of couple infertility, a collaborative retrospective clinical and cytogenetic study was performed, launched by the Association des Cytogénéticiens de Langue Franciaise (ACLF). The karyotypes of 3208 patients [2196 men (68.4%), 1012 (31.6%) women] included in ICSI programmes over a 3-year period in France were collected. A total of 183 aberrant karyotypes was diagnosed, corresponding to an abnormality frequency of 6.1% (134/2196) for men and 4.84% (49/1012) for women. The following frequencies of abnormalities were observed respectively for men and women: 1.23% (n = 27) and 0.69% (n = 7) for reciprocal translocations, 0.82% (n = 18) and 0.69% (n = 7) for Robertsonian translocations, 0.13% (n = 3) and 0.69% (n = 7) for inversions, 3.32% (n = 73) and 2.77% (n = 28) for numerical sex chromosome aberrations, and 0.59% (n = 13) and 0% for other structural aberrations. Among the male patients of this latter group, 0.40% (n = 9) had a Y chromosome abnormality. Among the male patients with numerical sex chromosome abnormalities, 2.23% (n = 49) were 47,XXY, 0.32% (n = 7) were 47,XYY, and 0.77% (n = 17) had a mosaicism for numerical sex chromosome anomalies. All the female patients with sex chromosome abnormalities (2.77%, n = 28) had mosaicism for numerical sex chromosome anomalies. Even if these cases-the significance of which was sometimes questioned-were disregarded in the analysis, 2.08% (21/1012) of abnormal karyotypes remained in women. An overall increased frequency of chromosomal aberrations was found, and this confirmed that in some cases of poor reproductive outcome there may be a contribution of maternal chromosome aberrations. Indeed, the existence of a chromosome abnormality in the female partner was associated with the group of infertile men in which there was no apparent cause of infertility.     

Determinants of parental decisions after the prenatal diagnosis of Down syndrome

We evaluated demographic factors and factors specific to the current pregnancy, and their relationship to the decision to continue or terminate a pregnancy after prenatal diagnosis of Down syndrome. All cases of Down syndrome (DS) managed at a tertiary care center from 1989–1997 were retrospectively analyzed with respect to maternal age, parity, gestational age, sonographic findings, insurance status, and race. Of 145 cases of trisomy 21, 19 (13.1%) of women chose continuation of pregnancy, while 126 (86.9%) chose termination. There were no differences between groups in parity, sonographic findings, insurance status, or race at the time of diagnosis. However, patients who chose termination were significantly older and earlier in gestation than those electing to continue their pregnancy. When Down syndrome is diagnosed prenatally, the choice of termination is related to maternal age and gestational age, but only gestational age is a significant independent predictor of pregnancy termination. Am. J. Med. Genet. 79:172–174, 1998. © 1998 Wiley-Liss, Inc.     

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.     

The centralized prenatal genetics screening program of New York City III: The first 7,000 cases

The Prenatal Diagnosis Laboratory of New York City (PDL) is a regional program for the prevention of genetic diseases. The administrative aspects of the establishment of the laboratory were described in papers I [Hsu, 1981] and II [Hsu and Benn, 1981] in this series. We now report our experience of the first 7,000 referrals to the laboratory. The laboratory achieved a success rate of 99.5% in obtaining a diagnosis. The frequency with which a repeat amniocentesis was required was 1.9%, usually attributable to inadequate initial amniotic fluid volume or condition. Cases were completed in an average time of 20.82 days. A total of 149 (2.13%) cytogenetic abnormalities were detected. There were 59 nonmosaic autosomal trisomies and 29 sex chromosome abnormalities. The incidence of unbalanced structural abnormalities (0.186%) was much higher than that reported in surveys of newborn infants largely because of the prenatal detection of cases with supernumerary chromosomes. The incidence of balanced structural abnormalities was also considerably higher than that found in surveys of the newborn population, in part because of the detection of subtle familial pericentric inversions of common chromosome regions (inv(Y)(p11q11), inv(2) (p11q13), and inv(1)(p11q13)). The incidence of cases with multiple independent chromosome abnormalities was no higher than expected by chance. A high incidence of mosaicism, pseudomosaicism, and maternal cell contamination was found. Screening for neural tube defects accounted for the detection of a further 16 abnormalities. Nearly all women with severely abnormal fetuses (trisomy 13, 18, 21) elected to terminate their pregnancy whereas only 62% of patients with a prenatally diagnosed sex chromosome abnormality elected to terminate their pregnancies. Full details of follow-up and confirmatory studies for unusual diagnoses are reported. Utilization of prenatal diagnosis in the New York City area has increased sharply since PDL became operational. The laboratory's success illustrates the role of a prenatal diagnosis laboratory that provides a service independent of the patient's financial status. The experience further shows the high degree of acceptance of prenatal diagnosis by individuals at high risk for a child with a genetic disorder.     

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。