Prenatal sonographic findings in 207 fetuses with trisomy 21

OBJECTIVE: The objective was to evaluate the contribution of second trimester ultrasound examination to the prenatal diagnosis of trisomy 21 in 207 fetuses with this aneuploidy. The type and frequency of abnormal sonographic findings were determined. Possible multiple malformation patterns, characteristic of trisomy 21 were sought. STUDY DESIGN: Singleton fetuses that had prenatal sonography during the second trimester, then underwent cytogenetic evaluation in our institution, made up the study population. The sonographic findings of 207 fetuses with trisomy 21 were analyzed. RESULTS: Between 1990 and 2004, fetal karyotyping was performed in 22,150 patients for different indications. An abnormal karyotype was diagnosed in 514 cases (2.3%); among them 207 fetuses with trisomy 21 were detected (40.3%). Abnormal sonography was seen in 63.8% of the cases. Structural anomalies were detected in 28.5% of the trisomy 21 fetuses, among them cardiac defects (15.9%), central nervous system anomalies (14.5%), and cystic hygromas (6.8%) were the most common. Of the minor markers, increased nuchal translucency (28%), pyelectasis (20.3%), and shorter extremities (8.7%) were common findings. CONCLUSIONS: Appropriate diagnosis of structural anomalies, looking for relatively easily detectable minor markers and incorporating fetal echocardiography into the second trimester sonographic protocol, may increase the contribution of mid-trimester ultrasound examination to diagnosing trisomy 21.     

Sonographic detection of fetuses with trisomies 13 and 18: accuracy and limitations

Nine fetuses having trisomy 13 and 15 fetuses with trisomy 18 were diagnosed by cytogenetic studies and also underwent a sonogram between 15 and 40 weeks. All nine fetuses with trisomy 13 had been prospectively identified as having sonographic findings suggestive of trisomy 13. Twelve of the 15 fetuses with trisomy 18 had sonographic abnormalities compatible with trisomy 18. Findings included abnormalities of the face and head, extremities, and diaphragmatic hernia. This report examines criteria for the ultrasound diagnosis of trisomies 13 and 18 and describes the accuracy of prenatal sonography for these diagnoses.     

产前超声指标评分法对胎儿18三体综合征的诊断价值

目的 探讨产前超声指标评分法对胎儿18三体综合征的诊断价值.方法 采用前瞻性方法对2004年1月至2009年12月在中山大学附属第一医院行产前超声筛查孕妇中,发现胎儿结构或软指标异常者行胎儿染色体核型检查,根据胎儿染色体核型分析结果,分为18三体组和非18三体组.对两组胎儿任一异常超声指标进行单因素logistic回归分析,分别计算各超声指标的阳性似然比(+LR).+ LR≥200的超声指标赋值3分,100≤+LR ＜200的超声指标赋值2分,+LR＜100的超声指标赋值1分.根据受试者工作特性( ROC)曲线,确定最佳诊断界值.结果 (1)符合入选标准孕妇共26 545例,产前超声检查可疑胎儿畸形或有超声软指标异常并接受胎儿染色体检查者共4044例,其中21三体93例,18三体59例,13三体19例,其他类型染色体异常134例,正常核型3739例.22 501例胎儿产前超声检查无异常,3985例胎儿出生后随访其结局也无异常,共计26 486例胎儿为非18三体组,59例18三体胎儿为18三体组.(2)18三体组59例胎儿均有2种及以上超声提示的结构异常,其中最常见为肢体异常(85％,50/59),其次是心脏畸形(83％,49/59)和中枢神经系统异常(75％,44/59).肢体异常中以重叠指最常见,心脏畸形中室间隔缺损最多见,中枢神经系统畸形中最常见为“草莓头”型.(3)经logistic回归分析,所有超声异常指标中可进入回归方程的是脉络膜囊肿、“草莓头”型、后颅窝池增宽、前脑无裂畸形、耳低置、室间隔缺损、左心发育不良综合征等16项,按照此16项超声指标的+LR值分别得出不同分值.(4)18三体组和非18三体组产前超声评分1分值分别为2％ (1/59)和2.549％(675/26 486),4分值分别为9％( 5/59)和0.215％ (57/26486),9分值分别为10％( 6/59)和0.004％( 1/26 486),10～16分值分别为32％ (19/59)和0.(5)以不同总评分值为超声诊断18三体征的截断值,计算出各分值的敏感度和特异度,ROC曲线下面积为0.999.以总评分4分为最佳诊断值,诊断18三体征的敏感度为0.966,特异度为0.997.结论 超声指标评分法对18三体综合征具有较好的诊断价值,以4分作为诊断18三体综合征截断值其诊断效价最高.     

Karyotyping for isolated neural tube defects. A report of two cases

BACKGROUND: Neural tube defects occur in approximately 1 in every 1,000 live births. In the United States, chromosomal abnormalities have been noted in 2-10% of fetuses with neural tube defects; however, there is no consensus on whether to offer karyotype analysis to patients with isolated neural tube defects found on ultrasound. CASE: We reviewed the prenatal diagnosis database for the University of Washington between 1985 and 1997. We report on two fetuses who, on ultrasound, were found to have "isolated" neural tube defects. Karyotype analysis revealed trisomy 18 in both fetuses. The pregnancies were subsequently terminated, and autopsy revealed subtle syndromic findings that were not identified on ultrasound. CONCLUSION: Fetuses with isolated neural tube defects also appear to have a high risk of chromosomal abnormalities, so patients should be offered fetal karyotyping to define recurrence risks for future pregnancies.     

First-trimester nuchal translucency measurement and echocardiography at 16 to 18 weeks of gestation in prenatal detection for trisomy 18

BACKGROUND: Trisomy 18, the second most common autosomal trisomy, has the highest incidence of congenital heart disease of all chromosomal abnormalities. This study assessed the use of nuchal translucency (NT) measurement and fetal echocardiography at 16 to 18 weeks of gestation in prenatal detection for trisomy 18. METHODS: Screening for chromosomal aneuploidy using fetal NT measurement was performed at 10 to 14 weeks of gestation. Detailed fetal echocardiography was performed at 16 to 18 weeks of gestation immediately before genetic amniocentesis for fetal karyotyping in singleton pregnancies with increased fetal NT thickness. RESULTS: Of the 3151 singleton pregnancies included in our study, 171 cases (5.4%) of increased (> or =3.0 mm) NT were noted. Fetal chromosomal abnormalities were identified in 22 (12.9%) of these pregnancies, including 9 with trisomy 21, 5 with trisomy 18, 4 with 45,X and 4 with unbalanced structural abnormalities. Major defects of the heart and the great arteries were identified in 13 (7.6%) of these pregnancies with increased NT. These included eight pregnancies that also had the diagnosis of chromosomal aneuploidy. Among the 22 fetuses with confirmed aneuploidy, all 5 fetuses with trisomy 18, 1 of the 4 fetuses with 45,X and 2 of the 9 fetuses with trisomy 21 had increased fetal NT thickness associated with abnormal fetal echocardiography findings. CONCLUSIONS: Screening for Down syndrome and cardiac defects using first-trimester fetal NT measurement in combination with fetal echocardiography at 16 to 18 weeks of gestation is a feasible and sensitive procedure for the prenatal detection of trisomy 18.     

Morphologische Befunde nach pränataler Ultraschalldiagnose

The results of prenatal ultrasound diagnosis are compared with the autopsy findings in 334 fetuses (15 weeks of gestation) after induced abortion for fetal abnormalities. In 57% of cases the ultrasound diagnosis was confirmed and found to be complete; in 33% the diagnosis was confirmed but autopsy revealed additional significant pathological features and in about 10% the prenatal ultrasound diagnosis was not confirmed by morphological examination of the fetus. Autopsy examination remains an important component of the evaluation of fetal losses after induced abortion.     

The role of fetal echocardiography in the prenatal diagnosis of aneuploidy based upon prenatally diagnosed patau syndrome fetuses (case analysis)

OBJECTIVE: Assessment of usefulness of the fetal echocardiography and genetic sonography in prenatal diagnosis trisomy 13 (retrospective analysis). MATERIAL AND METHOD: Between 1994-1999 at the Department for Diagnosis of Congenital Malformation at the Institute of PPMH in 11 fetuses with Patau Syndrome ultrasound and echocardiography examination were performed. In our study the most of cases come from low risk of pregnant women. RESULTS: Fetal heart defect was the most common anomaly diagnosed prenatally in fetuses with Patau Syndrome (7/11), the second one were central nervous system anomalies (6/11) and genitourinary system anomalies (6/11).     

Clinical utility of fetal autopsy and comparison with prenatal ultrasound findings.

OBJECTIVES: To present a comprehensive analysis of autopsy findings in 206 fetuses referred to our genetic center and to assess the clinical utility of fetal autopsy in reaching a final diagnosis, which is essential for counseling regarding the risk of recurrence. We also compared the autopsy findings with prenatal ultrasound findings to evaluate the potential benefit of fetal autopsy in fetuses terminated after prenatal diagnosis of malformations. STUDY DESIGN: Retrospective review of patient records in a tertiary referral genetic center in North India during 5-year period (April 2000-March 2005). This includes 206 fetuses, 138 terminated after detecting an anomaly in ultrasonogram and 68 spontaneous fetal losses. In all cases, fetal autopsy was carried out and complimented by radiography, karyotype wherever possible and histopathological examination wherever necessary. In fetuses with prenatally diagnosed malformations, ultrasound findings were compared with autopsy findings. RESULTS: Fetal autopsy was able to provide a definite final diagnosis in 59% (122/206) cases. Fetal autopsy confirmed the ultrasound findings in all cases but two. Moreover, autopsy provided additional findings in 77 cases and of these, 24 cases had a significant change of recurrence risk. CONCLUSION: This study confirms the utility of fetal autopsy in identifying the cause of fetal loss, which will help in the genetic counseling of the couple. In cases with prenatally diagnosed anomalies, the new information from fetal autopsy changes the predicted probability of recurrence in 18% cases. Even though the prenatal ultrasonogram reasonably predicts the malformations, fetal autopsy gives significant additional malformations in one-third of the cases and is essential for genetic counseling.     

Predictive value of increased nuchal translucency as a screening test for the detection of fetal chromosomal abnormalities

Objective.?The study aimed to estimate the incidence of increased nuchal translucency in the first trimester ultrasound scan results (cut-off limit 2.5 mm) and to evaluate the predictive value of increased nuchal translucency as a screening test for the detection of fetal chromosomal abnormalities.

Methods.?We used the ultrasound scan results of nuchal translucency evaluation and the results of chromosomal analysis of the invasive prenatal control performed as a result of increased nuchal translucency.

Results.?We collected 2183 nuchal translucency ultrasound scans in which we detected 21 embryos with a pathologic value (0.96%). We collected the data of 168 cases of invasive prenatal control due to increased nuchal translucency from which 122 cases were found. A total of 122 cases of pregnant women undergone an invasive prenatal diagnostic method due to increased nuchal translucency, of which 11 fetuses were found with trisomy 21 (Down syndrome) (9%), 3 fetuses with trisomy 13 (Patau syndrome) (2.45%), 3 fetuses with monosomy 45XO (Turner syndrome) (2.45%) and 1 fetus with translocation (0.8%).

Conclusions.?The positive predictive value of the increased fetal nuchal translucency as a screening test for the detection of fetal chromosomal abnormalities based on the results of the chromosomal-genetic analysis of the invasive prenatal diagnostic procedures is 14.8%.     

247例妊娠中期孕妇羊水细胞染色体核型分析

目的 分析妊娠中期进行产前诊断的孕妇羊水细胞染色体核型，了解此期异常核型发生的频率、类型及与各种产前诊断指征的关系。方法 对247例妊娠中期孕妇行羊膜腔穿刺术抽羊水作羊水细胞培养检查染色体核型。结果 发现异常核型14例，异常核型出现频率为5．67％，其中三体型7例，占异常核型的50％，分别为21三体4例，18三体2例，13三体1例；其次为平衡易位6例，占42．86％。高龄孕妇中21三体检出率为5．56％(1／18)，非高龄组为1．31％(3／229)，P=0．235，差异无显著性。15例产前常规B超检查发现胎儿发育异常的孕妇中，检出三体儿3例。结论 在有各种产前诊断指征的妊娠中期孕妇中，胎儿染色体异常发生率为5．67％，染色体三体为主要的异常核型。孕中期B超检查做为产前常规筛查可提高胎儿染色体异常的检出率。     

Sonographic features of trisomy 18 at midpregnancy

OBJECTIVE: To evaluate the sonographic characteristics of the fetuses with trisomy 18 at 16-22 weeks of gestation. METHODS: The subjects were recruited from pregnant women undergoing prenatal sonographic examinations at 16-22 weeks of gestation and subsequently proven to be trisomy 18. The results of ultrasound findings were retrospectively reviewed in 25 cases with chromosomes which were confirmed as trisomy 18. RESULTS: All cases had at least one abnormal sonographic finding. There was only one case that had no structural abnormality, but fetal growth restriction was documented. The common sonographic findings included fetal growth restriction, choroid plexus cysts, cardiac anomalies, clenched hand, omphalocele and cleft lip. Fetal growth restriction was the most common finding demonstrated in nearly half of all cases. Other less common findings were diaphragmatic hernia, abnormal head shape, polyhydramnios, single umbilical artery. CONCLUSION: Nearly all fetuses with trisomy 18 had characteristic sonographic patterns of abnormalities demonstrated at midpregnancy. Detailed ultrasound at midpregnancy could effectively screen fetuses with trisomy 18 for further genetic testing.     

146例非免疫性水肿胎儿的产前染色体分析

目的:分析非免疫性水肿胎儿的产前诊断结果,明确其染色体异常的类型。方法:选取146例非免疫性水肿胎儿,通过经腹绒毛取样、羊膜腔穿刺、脐静脉穿刺及流产后取胎儿组织送检的方法进行胎儿染色体核型及低覆盖度大规模平行测序技术(CNV-seq)的分析。结果:146例胎儿的染色体异常发生率为48.6%(71/146),其中性染色体异常29例,21-三体19例,18三体13例,13-三体3例,其他染色体异常1例,致病性拷贝数变异6例。染色体异常检出率随着孕周的增加而降低,<14孕周、14~27孕周、≥28孕周孕妇的染色体异常检出率分别为68.4%(39/57)、40.8%(31/76)和7.7%(1/13)。水肿胎儿最常合并的超声结构异常依次为NT/NF增厚、颈部水囊瘤及心脏异常,其染色体异常检出率分别为59.5%、59.2%及51.9%。结论:染色体异常是胎儿水肿的常见病因,特别是早中孕期出现水肿的胎儿,检出率较高。对于水肿胎儿的产前诊断,除了常规的核型以外,需重视拷贝数变异的检测。     

The role of fetal echocardiography and genetic sonography in prenatal diagnosis of the Edward's syndrome--analysis of the thirty case diagnosed at the Department of the Diagnosis for Fetal Malformations at the Institute "Polish Mother's Memorial Hospital."

OBJECTIVE: Trisomy 18 (Edward's syndrome) is one of the most common chromosomal aberration in fetuses/neonates. The aim of our study was to assess the usefulness of the fetal echocardiography and genetic sonography in prenatal diagnosis trisomy 18 (retrospective analysis). MATERIAL AND METHOD: Between 1994-2000 at the Institute "Polish Mother's Memorial Hospital" 30 cases of trisomy 18 were diagnosed. RESULTS: Every fetus/neonate presented with congenital anomalies. The most common were: intrauterine growth retardation (96%) and congenital heart defects (92%). CONCLUSIONS: Retrospective analysis indicates the great role of "genetic sonography" and fetal echocardiography in prenatal diagnosis of trisomy 18.     

Severe bilateral renal disease: correlation of antenatal and autopsy findings

We report 20 infants with severe bilateral renal disease examined by prenatal ultrasound and by autopsy. In 17, the prenatal and pathologic diagnoses correlated well. Although the prenatal and autopsy findings differed in the three remaining cases, the autopsy confirmed the presence of severe bilateral renal abnormalities. All 20 pregnancies were complicated by oligohydramnios, which was severe in 60 per cent. Most of these fetuses had malformation of other organ systems. This series supports the utility of prenatal ultrasound examinations, but emphasizes the need for postnatal evaluation of congenital renal disease including pathologic examination of tissue when possible for correct classification and genetic counselling.     

Absence of fetal nasal bone and aneuploidies at first-trimester nuchal translucency screening in unselected pregnancies

OBJECTIVES: The absence of nasal bone (NB) has been noted in trisomy 21 fetuses at first-trimester ultrasound, in high-risk pregnancies. In this study, the nasal bone was evaluated in relation to fetal karyotype, in unselected pregnancies. METHODS: From September 2001 to September 2002, the fetal facial profile was examined at the 11 to 14 weeks' scan for screening by nuchal translucency (NT). Risks for trisomy 21 were calculated using the Fetal Medicine Foundation's software, and the presence or absence of NB was noted. Prenatal karyotype and pregnancy outcomes were recorded. RESULTS: NT screening was performed in 5532 fetuses from 5425 pregnancies (85 twins, 8 triplets, 2 quadruplets). The visualization of fetal profile was obtained in 5525 fetuses (99.8%), and in 5491 fetuses (99.4%) the NB was present and in 34 cases (0.6%) it was absent. Fetal karyotype and pregnancy outcome were available in 3503 pregnancies, and 40 chromosomal abnormalities were diagnosed (27 trisomies 21, 5 trisomies 18, 2 trisomies 13, 3 Turner syndromes, 1 partial trisomy 9 and 2 others). The NB was absent in 19 (70%) trisomies 21, 4 trisomies 18 (80%), 2 Turner syndromes (66%), in the partial trisomy 9, in 7 normal karyotype fetuses (0.2%), and in a case with spontaneous first-trimester abortion before prenatal diagnosis. A significant difference was found between NT thickness, expressed as a multiple of the median, in trisomy 21 fetuses with present and absent nasal bone. CONCLUSIONS: The absence of NB at 11 to 14 weeks is more frequent in fetuses with trisomy 21 and other aneuploidies than in normal karyotype fetuses.     

Prenatal diagnosis of a fetus with distal 10q trisomy.

Distal 10q trisomy is a well-defined but rare syndrome. Most cases are diagnosed in infancy or in childhood and rarely include prenatal findings. We present a case of fetal distal 10q trisomy with abnormal prenatal sonographic findings. A 19-year-old primigravida was referred for genetic counselling at 18 gestational weeks because her husband had a familial history of congenital anomalies. Genetic amniocentesis was thus performed and showed fetal distal 10q trisomy (10q24.1-->qter), 46,XX,der(22)t(10;22)(q24.1;p11.2)pat, resulting from paternal t(10;22) reciprocal translocation. Level II ultrasonograms further demonstrated bilateral hydronephrosis, ventricular septal defect and facial dysmorphism ascertained by three-dimensional ultrasound. The pregnancy was terminated at 22 gestational weeks. Post-mortem autopsy confirmed the sonographic findings. We suggest that abnormal prenatal sonographic findings such as cardio-vascular, renal and facial malformations should alert cytogeneticists to search for subtle chromosomal abnormalities.     

New ultrasonographic markers of aneuploidies: nasal bones

The ultrasound sign of the absence of nasal bones in aneuploidies is discussed. Among several skeletal abnormalities in trisomy 21 fetuses, the absence or delay in the development of the nasal bones has been described by radiological and histological studies. The finding of absent nasal bones is recognizable by prenatal ultrasound examinations in first- and second-trimester fetuses, and about two-thirds of fetuses with trisomy 21 reveal absent nasal bones. There is evidence that an appropriate technique is required to visualize the fetal nasal bones by ultrasound. As, from preliminary studies, the absence of nasal bones does not appear to be related to fetal nuchal thickness, the two signs could be combined in a single test for prenatal screening of trisomy 21 that seems to be very accurate.

Prenatal ultrasound studies have shown the absence of nasal bone visualization also in first-trimester fetuses affected by trisomy 18, Turner's syndrome and trisomy 9.     

Chromosomal defects and associated malformations in fetal cleft lip with or without cleft palate

OBJECTIVE: To describe the incidence, associated features including chromosomal defects in fetuses, with cleft lip and/or palate and assess the need for karyotyping. METHODS: Retrospective study of 62 cases of prenatally diagnosed facial cleft lip and/or palate in a tertiary fetal medicine unit between January 1991 and December 1999. Chromosome analysis was performed in all fetuses with associated ultrasound findings and in 14 (39%) fetuses with isolated facial clefts. RESULTS: Associated abnormalities were detected in 26 (42%) of the 62 fetuses of which 22 (35%) fetuses had multiple other abnormalities. Central nervous system abnormalities and limb malformations were the most common. Three fetuses had genetic syndromes confirmed after birth. All fetuses with isolated clefts were chromosomally normal, whereas 15 of the 26 with additional abnormalities (58 or 24% of the total group) had chromosomal defects (eight cases of trisomy 13, five of trisomy 18, one unbalanced translocation between chromosomes 7 and 8, and one deletion 4p-). All 22 women who chose not to undergo fetal karyotype analysis delivered phenotypically normal infants. There were five midline clefts; each of them was associated with additional sonographic findings and four were associated with holoprosencephaly. CONCLUSION: Isolated facial clefting is not associated with an increased risk for chromosomal defect. Amniocentesis is recommended when facial cleft is found in association with additional ultrasonographic abnormalities as it is unnecessary for isolated clefts.     

胎儿肾盂扩张的产前诊断及转归

目的 研究不同程度胎儿肾盂扩张的产前诊断及其临床转归,为产前遗传咨询提供依据.方法 对孕妇作产前超声检查,发现胎儿肾盂扩张时,测量肾盂前后径(APD),按肾盂APD值分别纳入轻度、中度、重度肾盂扩张组,并进行监测和随访,部分胎儿作染色体核型检测.结果 128例胎儿存在肾盂扩张,引产胎儿28例,24例合并胎儿畸形,7例存在染色体异常.继续妊娠的100例胎儿中,有155侧肾盂扩张,轻度组86侧肾盂扩张,自行消失83侧,占96.5%(83/86).中度组39侧肾盂扩张,自行消失24侧,占61.5%(24/39);生后手术治疗8侧,占20.5%(8/39).重度组30侧肾盂扩张,自行消失1侧,占3.3%(1/30),生后手术治疗22侧,占73.3 %(22/30).肾盂扩张自行消失率随扩张程度的加重而下降(x2=88.730,P<0.01);出牛后患儿手术率与产前胎儿肾盂扩张的程度呈正相关(x2=2.045,P<0.01).69例胎儿行染色体核型检测,7例异常,占10.1%.结论 胎儿单纯的轻、中度肾盂扩张多数可自行消失,若合并其他器官异常,则染色体异常的风险增大;中重度肾盂扩张者,易合并泌尿系或其他器官异常.