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。     

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。     

广州地区羊水染色体核型分析的产前诊断及相关遗传咨询

目的探讨羊水细胞染色体核型分析在产前诊断中的意义及其相关的遗传咨询。方法羊膜腔穿刺术抽取羊水进行细胞培养,收获中期细胞后制片,常规G显带,进行核型分析。结果在520例羊水细胞培养病例中发现异常染色体核型18例,其中染色体结构异常6例,21三体3例,18三体2例,13三体1例,性染色体异常3例,嵌合体3例。正常多态性核型19例。结论对具有各种产前诊断指征的孕妇进行羊水细胞染色体核型分析是十分必要的,可有效降低出生缺陷率。     

Cystic hygroma and hydrops fetalis in a fetus with trisomy 13

We report a case of trisomy 13 with cystic hygroma and generalized hydrops fetalis diagnosed prenatally by routine ultrasound prior to genetic amniocentesis in a 34-year-old woman. Although fetal cystic hygroma is usually associated with a 45,X karyotype, this and other previous reports suggest that it may be seen in association with other chromosomal and nonchromosomal abnormalities as well. Thus, a diagnosis of Turner Syndrome should not be made on the basis of a cystic hygroma observed by prenatal sonography alone.     

Investigation of maternal blood enriched for fetal cells: Role in screening and diagnosis of fetal trisomies

Prenatal diagnosis of chromosomal abnormalities relies on assessment of risk followed by invasive testing in the group with highest risk. Assessment of risk by a combination of maternal age and fetal nuchal translucency and invasive testing in the 5% of the population with the highest risk would identify about 80% of trisomy 21 pregnancies. Preliminary reports suggest that chromosomal abnormalities can also be diagnosed by fluorescent in situ hybridization (FISH) in maternal blood enriched for fetal cells. This study examines the potential role of this method on the prenatal diagnosis of fetal trisomies. Maternal blood was obtained before invasive testing in 230 pregnancies at 10–14 weeks of gestation. After enrichment for fetal cells, by triple density centrifugation and anti-CD71 magnetic cell sorting, FISH was performed and the proportion of cells with positive signals in the chromosomally normal and abnormal groups was determined. Fetal karyotype was normal in 150 cases and abnormal in 80 cases, including 36 with trisomy 21. Using a 21 chromosome-specific probe, three-signal nuclei were present in at least 5% of the enriched cells from 61% of the trisomy 21 pregnancies and in none of the normal pregnancies. For a cut-off of 3% of three-signal nuclei the sensitivity for trisomy 21 was 97% for a false positive rate of 13%. Similar values were obtained in trisomies 18 and 13 using the appropriate chromosome-specific probe. Examination of fetal cells from maternal blood may provide a noninvasive prenatal diagnostic test for trisomy 21 with the potential of identifying about 60% of affected pregnancies. Alternatively, this technique can be combined with maternal age and fetal nuchal translucency as a method of selecting the high-risk group for invasive testing. Potentially, 80% of trisomy 21 pregnancies could be identified after invasive testing in less than 1% of the pregnant population. Am. J. Med. Genet. 85:66–75, 1999. © 1999 Wiley-Liss, Inc.     

Increased nuchal translucency in trisomy 13 fetuses at 10–14 weeks of gestation

In a multicenter screening study for trisomy 21 involving ultrasonographic measurement of fetal nuchal translucency thickness (NT) at 10–14 weeks of gestation, 100,311 singleton pregnancies with a live fetus were examined. There were 46 cases of trisomy 13, and in 33 (72%) of these, the NT was above the 95th centile. The estimated risk for trisomy 21, based on maternal age-related risk for this chromosomal abnormality and fetal NT, was above 1 in 300 in 37 (80.1%) of the trisomy 13 fetuses. The fetal crown-rump length was significantly reduced, but the fetal heart rate was increased, being above the 95th centile in 64% of cases. Additionally, 24% of trisomy 13 fetuses had holoprosencephaly and 10% had exomphalos. This study has demonstrated that at 10–14 weeks of gestation, about 80% of fetuses with trisomy 13 can be identified in a screening program for trisomy 21, based on a combination of maternal age and fetal NT. Am. J. Med. Genet. 86:205–207, 1999. © 1999 Wiley-Liss, Inc.     

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。     

湘潭地区孕早中期联合产前筛查与产前诊断的临床应用价值探讨

目的 探讨孕早中期孕妇联合产前筛查与产前诊断对预防出生缺陷的实用价值.方法 应用全自动时间分辨荧光免疫法对18247例孕妇血清标志物联合筛查,高风险孕妇通过羊水产前诊断进行效果评价.结果 筛查出唐氏综合征高风险873例,18-三体高风险91例,NTD高风险者104例,总阳性率5.85％.有583例孕妇接受羊水产前诊断,占筛查高危的60.5％.确诊胎儿染色体数目异常19例(唐氏综合征13例、18-三体综合征2例、性染色体异常4例);染色体结构异常13例;B超确诊脊柱裂或脑畸形13例.结论 联合产前筛查与产前诊断是预测不良妊娠结局的有效指标,对降低出生缺陷有重要的临床意义.     

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.     

Rates and survival of individuals with trisomy 13 and 18 Data from a 10-year period in Denmark

Rates and survival figures for trisomy 13 and trisomy 18 have been calculated for Denmark (DK) based on a 10-year period (1977-86). The data have been ascertained through The Danish Central Cytogenetic Register, all cytogenetic laboratories in DK, paediatric departments throughout the country. The Medical Birth Register and The Register of Causes of Death in DK. Nineteen liveborn probands with trisomy 13 and 76 liveborn probands with trisomy 18 were found. No stillborn cases with trisomy 13 but 6 with trisomy 18 were found. By prenatal diagnosis 19 probands with trisomy 13 and 46 with trisomy 18 were found. Based on liveborn and stillborn probands, the prevalence at birth was 1 per 29,374 for trisomy 13 and 1 per 6806 for trisomy 18. The median survival for trisomy 13 was 2.5 days, while the same figure for trisomy 18 was 6.0 days. The rates calculated seem rather low compared to earlier studies.     

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.     

A girl with metopic synostosis and trisomy 13 mosaicism: case report and review of the literature

Trisomy 13, or Patau syndrome is a rare chromosomal disorder characterized by a triad of cleft lip and palate, postaxial polydactyly and microcephaly. Complete, partial, or mosaic forms of the disorder can occur. Mosaic trisomy 13 is very rare, it occurs in only 5% of all patients with trisomy 13 phenotype. Metopic synostosis (MS) is premature fusion of the metopic suture, which is part of the frontal suture. It results in a V-shaped abnormality at the front of the skull. MS may occur in a syndromic or nonsyndromic form. We report on a 24-day-old girl with hypotonia, MS, trigonocephaly, capillary hemangioma, hypotelorism, upward slanting palpebral fissures, epicanthal folds, small nose with anteverted nares, high palate, ankyloglossia, long philtrum, low-set ears, short neck, postaxial polydactyly of both hands and feet and congenital heart defect. Cytogenetic analysis demonstrated trisomy 13 mosaicism; 46,XX[58]/47,XX,+13[42]. Although MS has been previously reported in complete and partial forms of trisomy 13, it has not been reported in mosaic form of trisomy 13. Our report supports the evidence that trisomy 13 causes MS. It also emphasizes the need for cytogenetic investigations in patients presenting with MS and multiple congenital anomalies for providing accurate diagnosis, genetic counseling, and prenatal diagnosis.     

Investigation of maternal blood enriched for fetal cells: role in screening and diagnosis of fetal trisomies.

Prenatal diagnosis of chromosomal abnormalities relies on assessment of risk followed by invasive testing in the group with highest risk. Assessment of risk by a combination of maternal age and fetal nuchal translucency and invasive testing in the 5% of the population with the highest risk would identify about 80% of trisomy 21 pregnancies. Preliminary reports suggest that chromosomal abnormalities can also be diagnosed by fluorescent in situ hybridization (FISH) in maternal blood enriched for fetal cells. This study examines the potential role of this method on the prenatal diagnosis of fetal trisomies. Maternal blood was obtained before invasive testing in 230 pregnancies at 10-14 weeks of gestation. After enrichment for fetal cells, by triple density centrifugation and anti-CD71 magnetic cell sorting, FISH was performed and the proportion of cells with positive signals in the chromosomally normal and abnormal groups was determined. Fetal karyotype was normal in 150 cases and abnormal in 80 cases, including 36 with trisomy 21. Using a 21 chromosome-specific probe, three-signal nuclei were present in at least 5% of the enriched cells from 61% of the trisomy 21 pregnancies and in none of the normal pregnancies. For a cut-off of 3% of three-signal nuclei the sensitivity for trisomy 21 was 97% for a false positive rate of 13%. Similar values were obtained in trisomies 18 and 13 using the appropriate chromosome-specific probe. Examination of fetal cells from maternal blood may provide a noninvasive prenatal diagnostic test for trisomy 21 with the potential of identifying about 60% of affected pregnancies. Alternatively, this technique can be combined with maternal age and fetal nuchal translucency as a method of selecting the high-risk group for invasive testing. Potentially, 80% of trisomy 21 pregnancies could be identified after invasive testing in less than 1% of the pregnant population.     

A concealed penis mimicking penile agenesis in an infant with trisomy 13

Penile agenesis results from failure in the development of the genital tubercle and is rarely associated with chromosomal abnormalities. We report on an echographic prenatal diagnosis of penile agenesis associated with trisomy 13. At birth, the contour of the penile shaft and the glans could not be seen. However, a careful palpation allowed us to determine that the penile shaft was concealed and normal in size, rather than penile agenesis being present. To our knowledge, a concealed penis associated with trisomy 13 has not previously been described.     

Sex determination,differentiation and intersexuality in placental mammals. By R. H. F. Hunter. Cambridge: Cambridge University Press, 1995, pp 310

We have reported previously a 10% aneuploidy detection rate among 39 cases of fetal neural tube defects (NTD). Subsequently we amassed an additional experience of over 17,000 prenatal diagnosis cases over a 5-year period. During this period 106 cases of NTDs were identified; 44 with anencephaly, 62 with open spina bifida. The average maternal age of this population with NTDs was 29 years (15–40); 6 patients declined amniocentesis. Six of 100 cytogenetic studies were aneuploid; one anencephalic fetus had inherited a maternal marker chromosome, and 5 NTD cases had trisomy 18. The average maternal age of the aneuploid cases was 31 (19–40); 3 were 35 years or older. Four of 5 trisomy 18 cases had multiple congenital anomalies (MCA). The overall aneuploidy detection rate in our cohort was 5–6%, while aneuploidy occurred in 2% of the isolated NTD cases, and 24% of the MCA cases. Combining the earlier experience, 4/39 aneuploidy (2 trisomy 18, 4p+, del 13q) yields an aneuploidy detection frequency of 10/145 (7%), of which most (7/10) had trisomy 18. These data support fetal karyotyping for accurate diagnosis, prognosis, and recurrence-risk counseling. © 1996 Wiley-Liss, Inc.     

Mosaic partial trisomy 17q2.

Examination of an infant born after prenatal diagnosis of mosaic partial trisomy 17q2 showed the unique phenotypic features of this chromosomal abnormality, that is, frontal bossing, large mouth, brachyrhizomelia, and hexadactyly. Amniocentesis was performed because of polyhydramnios and ultrasound diagnosis of fetal craniofacial dysmorphology and rhizomelic shortening of the limbs. Chromosomal mosaicism was restricted to fetal tissue and amniotic fluid cells. The placental chromosomal complement was normal, suggesting that the abnormality developed after differentiation of embryonic and trophoblastic cells. This emphasises the usefulness of cytogenetic evaluation of placental, fetal, and amniotic fluid cells in delineating the pathogenesis of congenital abnormalities.     

The impact of cardiac surgery in patients with trisomy 18 and trisomy 13 in Japan

Congenital heart defects (CHD) are very common in patients with trisomy 18 (T18) and trisomy 13 (T13). The surgical indication of CHD remains controversial since the natural history of these trisomies is documented to be poor. To investigate the outcome of CHD in patients with T18 and T13, we collected and evaluated clinical data from 134 patients with T18 and 27 patients with T13 through nationwide network of Japanese Society of Pediatric Cardiology and Cardiac Surgery. In patients with T18, 23 (17%) of 134 were alive at this survey. One hundred twenty-six (94%) of 134 patients had CHDs. The most common CHD was ventricular septal defect (VSD, 59%). Sixty-five (52%) of 126 patients with CHD developed pulmonary hypertension (PH). Thirty-two (25%) of 126 patients with CHD underwent cardiac surgery and 18 patients (56%) have survived beyond postoperative period. While palliative surgery was performed in most patients, six cases (19%) underwent intracardiac repair for VSD. Operated patients survived longer than those who did not have surgery (P < 0.01). In patients with T13, 5 (19%) of 27 patients were alive during study period. Twenty-three (85%) of 27 patients had CHD and 13 (57%) of 27 patients had PH. Atrial septal defect was the most common form of CHD (22%). Cardiac surgery was done in 6 (26%) of 23 patients. In this study, approximately a quarter of patients underwent surgery for CHD in both trisomies. Cardiac surgery may improve survival in selected patients with T18.     

Multiple congenital anomalies in a child born after prenatal diagnosis of trisomy 20mosaicism

The clinical significance of trisomy 20 mosaicism in amniotic fluid cultures has remained unclear so far. We report data on a child with multiple congenital anomalies born after a diagnosis of true trisomy 20 mosaicism in 65% of amniotic fluid cells. The child had generalized dysmorphic features, including facial dysmorphy resembling those of a child with Williams syndrome. The boy also had hypotonia and language delay. Although most of the published cases do not mention any abnormalities in children born after prenatal diagnosis of trisomy 20 mosaicism, the distinct cranio-facial features and the similarities to previous reports of partial or complete chromosome 20 mosaicism raises the possibility that a recognizable pattern of malformation might be associated with the prenatally diagnosable condition in some cases.     

Routine prenatal diagnosis of aneuploidy by FISH studies in high‐risk pregnancies

This study is a prospective clinical trial with fluorescent in situ hybridization (FISH) as a “routine” test for prenatal detection of the most common aneuploidies in high‐risk pregnancies. Since April 1996, FISH studies with multicolor, commercially available, specific probes for chromosomes 13, 18, 21, X, and Y have been routinely performed in our cytogenetic laboratory on uncultured chorionic villous samplings (CVS), amniotic fluid samples, or fetal blood obtained by cordocentesis from patients with major or minor fetal anomalies detected by ultrasonography. Among the 4,193 prenatal samples analyzed between April 1996 and June 1998, routine FISH studies were ordered by the referring physicians on 301 (7.2%) cases. Aneuploidies were detected in 32 (10.6%) samples. Fourteen trisomy‐21, 10 trisomy‐18, 3 trisomy‐13, 4 monosomies of X, and 1 case of triploidy were diagnosed by FISH. All 1,505 hybridizations were informative, and all 301 results were available and reported to the referring physicians in 24–48 hr. All relevant FISH results were confirmed by subsequent cytogenetic analysis. In 10 (3.8%) cases with normal FISH results, the final cytogenetic analysis revealed abnormal chromosomal rearrangements that could not be detected by the routine FISH studies. We conclude that rapid FISH analysis of interphase, uncultured fetal cells is an accurate and very sensitive method for routine prenatal diagnosis of the most common aneuploidies in high‐risk pregnancies. Am. J. Med. Genet. 90:233–238, 2000. © 2000 Wiley‐Liss, Inc.     

Survival in trisomy 18

Prenatal diagnosis of trisomy 18 by amniocentesis in the latter half of pregnancy is now a common event. Accurate prognostic information is crucial for families making decisions about delivery management. Three recently published studies showed much shorter survival for trisomy 18 than was reported by earlier papers. For this reason, we studied trisomy 18 survival. We examined chromosome laboratory records to find all trisomy 18 diagnoses made in Utah between 1979 and 1988. Death certificates and hospital records were used to determine survival. We found 64 live-born cases with trisomy 18 out of 388,563 total births over the 10-year period, a prevalence of 1/6071. Our results show a median survival of 4 days and a 1 week survival of 45%, similar to that reported in the 3 recent studies. However, we had a significantly greater survival at 6 months (9% in Utah versus 3% in Denmark) and 1 year (5% versus 0 in the 3 studies). In contrast to recent studies, earlier investigations showed 80% survival at 2 weeks and 8% at 1 year. It is not surprising that recent studies show shorter survival, since in the 1960s the diagnosis was typically not made until age 2 months. With prenatal and neonatal diagnosis many cases which would have died prior to detection in earlier times are now diagnosed. The longer survival discrepancies are more difficult to explain, but may simply be due to small numbers. © 1994 Wiley-Liss, Inc.