胎儿细胞异常核型发生频率和类型及其与产前诊断指征关系研究

目的:利用染色体微阵列分析(CMA)技术比较不同产前诊断指征高危妊娠者的胎儿细胞样本中异常核型发生频率与类型.方法:回顾分析2017年5月-2019年10月在某妇幼保健院行侵入性产前诊断术的妊娠者2014例的病例资料.结果:在2014例样本中,检出胎儿异常核型及染色体拷贝数变异(致病或可能致病)223例,临床意义未明拷...     

嵌合型13环状染色体综合征的产前诊断

目的 对1例孕17周超声发现室间隔缺损,主动脉与肺动脉内径接近,单脐动脉的胎儿进行分子细胞遗传学分析。方法 对羊水细胞进行G显带染色体核型分析和染色体微阵列分析,父母外周血进行G显带染色体核型分析。结果 G显带分析提示胎儿核型为45,XY,-13[45]/46,XY,r(13)(p11q34)[35],父母核型均正常,胎儿染色体异常为新发突变。CMA检测胎儿为 13号染色体长臂q32.3q34存在13.6Mb缺失,为致病性CNVs,13号染色体长臂q31.3q32.3存在7.2Mb重复,为致病性未明CNVs。不同检测方法嵌合情况存在差异。结论 本例13单体,13环状染色体嵌合体胎儿产前超声诊断表现为心血管发育畸形,相关发育基因的缺失和重复可能是表型变异的主要原因。     

微阵列比较基因组杂交技术在多发畸形中的临床应用研究

目的 将微阵列比较基因组杂交技术用于多发畸形胎儿的分子遗传学分析,并探讨其在辅助常规染色体核型分析中的价值.方法 选择2012年2月-2015年5月在解放军总医院产前诊断中心超声诊断为胎儿全身多发畸形的妊娠妇女31例,孕妇年龄20～37岁,孕周21～27周.在超声引导下获取羊水或脐血,再行常规染色体核型分析和微阵列比较基因组杂交检测.结果 31例多发畸形脐血样本均进行了G显带染色体核型分析和微阵列比较基因组杂交检测.染色体核型分析中4例培养失败,1例无核分裂象,培养成功的26例中染色体核型分析正常者23例,异常3例,核型异常率为11.54％(3/26).微阵列比较基因组杂交检测中有4例未发现致病性染色体缺失/重复,21例发现了微缺失和微重复,但均为染色体多态性,不具有致病性,6例检查异常,异常率19.35％(6/31).结论 微阵列比较基因组杂交技术具有分辨率高、覆盖广泛的优势,不仅弥补了培养失败和细胞活力不够无法进行常规染色体核型分析的缺陷,还能从亚显微结构发现缺失和重复,对于畸形原因的分析和解释提供了重要依据.     

67例颈后皮肤皱褶增厚胎儿产前诊断结果分析

 目的 探讨颈后皮肤皱褶厚度(nuchal fold, NF)增厚胎儿染色体异常的类型及分布,明确NF增厚的临床意义。方法 以≥14周胎儿NF≥6 mm为NF增厚诊断标准,回顾性分析2013-01至2016-12医院67例NF增厚胎儿的产前诊断临床资料,其中18~23⁺⁶周胎儿行羊膜腔穿刺,≥24周胎儿行超声引导下脐静脉穿刺,死胎在流产后取胎儿组织送检,分析胎儿标本的染色体核型及基因拷贝数变异结果。结果 67例NF增厚胎儿染色体异常发生率为13.4%(9/67),其中21-三体4例,18-三体2例,性染色体异常1例,病理性致病性基因拷贝数变异2例;孤立性NF增厚胎儿的染色体异常发病率为3%(1/33),显著低于综合征性NF增厚胎儿(23.5%,8/34)。结论 NF是胎儿染色体异常的重要指标,对于NF增厚的胎儿的产前诊断,除了常规检查核型以外,还需要重视检测基因拷贝数变异,特别是综合征性的NF增厚胎儿。     

MRI联合超声与染色体微阵列分析技术在中枢神经系统异常胎儿产前的应用

目的探讨核磁共振(MRI)联合超声(US)与染色体微阵列分析技术(chromosomal microarry analysis,CMA)在中枢神经系统异常胎儿产前诊断中的应用。方法选取我院接受治疗的226例怀疑中枢神经系统异常胎儿的孕妇为此次观察的对象,所有孕妇胎儿均接受MRI联合US与CMA进行相关的检查。比较在不同检查方法下对于胎儿中枢神经系统异常的检出率、灵敏度以及特异度,比较异常胎儿在每种检查下的影像学图像表现。结果MRI检查在视野、分辨率、组织特异性以及脑沟、裂、回的图像都要比US检查的质量要高(P<0.05),而血流显示以及脉络丛室管膜的显示要比US检查的质量要低(P<0.05);总体来看MRI检查(91.50%)对中枢神经系统出现异常的总检出率要比US检查(87.17%)的高,两者联合检查的灵敏度、特异度分别为91.04%、21.43%;神经系统出现异常的226例胎儿中,经CMA检测其中有13例检测出染色体核型异常(6.77%),41例检查出CNVs(21.35%),包括24例致命性CNVs(12.50%),13例胎儿检查出VOUS(6.77%);其中11例选择了继续妊娠分娩,2例选择了引产,可见有选择继续妊娠的比例为84.62%。结论MRI联合US与CMA能够较为准确地诊断产前中枢神经系统异常胎儿,特别是对于在超声结构检查异常的胎儿,结合MRI能够更加有效的于产前对中枢神经系统异常胎儿进行诊断,值得临床推广。     

荧光染色体原位杂交技术在产前诊断中的应用

目的 建立并优化荧光染色体原位杂交技术并评价其在胎儿21、18、13、X和Y染色体数目异常产前诊断中的临床应用价值.方法 常规穿刺取羊水或脐带血样本196例,经低渗、固定、制片、老化等,直接利用两组特异性探针(GLP 13/GLP 21和CSP18/CSP X/CSP Y)进行原位杂交,快速检测羊水或脐带血细胞中21、18、13、X和Y染色体的数目,并同时对样本进行经典的细胞培养和染色体核型分析.结果 以≥90％的细胞显示的荧光信号点数目作为染色体数目的判断标准,正常情况下GLP 13/GLP 21探针组显示2个绿色荧光点/2个红色荧光点,CSP18/CSP X/CSPY探针组显示2个蓝绿色荧光点/2个黄色荧光点(女性)或者2个蓝色荧光点/1个黄色荧光点/1个红色荧光点(男性).196例羊水或脐血均在72～96h内给出报告,检出21三体综合征7例、l8三体综合征2例、性染色体异常(47,XYY)1例,与1个月后报告的染色体核型分析结果一致.结论 荧光染色体原位杂交方法可用于快速产前诊断胎儿21、18、13、X、Y染色体数目异常,与常规的染色体核型分析技术结合,可快速准确地检测胎儿染色体的非整倍体异常.     

母血浆中游离胎儿DNA检测在染色体非整倍体筛查中的应用

目的母血浆中游离胎儿DNA检测在染色体非整倍体的无创产前诊断中的实用价值及临床意义。方法选择孕中期血清学筛查高风险、高龄妊娠等因素,孕龄在15～26周之间,且拒绝行侵入性产前诊断的孕妇。进行母血浆中游离胎儿DNA的高通量测序,阳性结果孕妇,通过羊膜腔穿刺、羊水细胞培养、染色体核型分析确定染色体非整倍体情况。结果1269例孕妇血浆样本经高通量基因测序检测到22个结果异常,羊水染色体核型分析1O例21-三体、3例18-三体、性染色体异常6例,3例性染色体误诊。无创胎儿21-三体、18-三体综合征检出正确率达100％,但胎儿性染色体检测准确率较低,约为66．7％。结论高通量基因组测序技术具有无创性,且与传统羊水染色体核型分析相比,诊断胎儿21-三体、18-三体综合征的特异性有较高的一致性。     

摇椅足的产前超声诊断与相关异常分析

目的探讨摇椅足的产前超声诊断与合并其他异常的相关性。方法收集2012年1月～2017年12月曾在我院产前检查并经手术或尸解证实的摇椅足病例,分析产前超声检查特征、合并其他畸形及染色体结果。结果摇椅足病例22例,产前诊断19例,2例误诊为足内翻,1例漏诊。孤立性摇椅足1例,非孤立性摇椅足21例。9例行胎儿染色体核型分析,其中4例染色体异常。结论胎儿摇椅足常合并多系统畸形,以此为线索发现胎儿足后跟及足底明显凸出时考虑摇椅足诊断。     

无创DNA产前检测在高龄孕妇胎儿染色体异常诊断中应用价值

目的探讨无创DNA产前检测(NIPT)在高龄孕妇胎儿非整倍体染色体疾病产前筛查中的临床应用价值。方法回顾性分析自2015年12月至2018年3月于解放军967医院优生优育中心就诊的587例进行NIPT的高龄孕妇临床资料。按年龄将孕妇分为35～39岁组(n=425)与年龄≥40岁组(n=162)。采用NIPT高通量测序检测孕妇外周血中胎儿游离DNA。检测结果提示,21-三体、18-三体、13-三体及性染色体高风险者行羊膜腔穿刺抽取羊水进行羊水胎儿染色体核型分析。对检测结果提示低风险者通过电话随访进行验证。结果 587例受检者NIPT检测结果提示,胎儿非整倍体染色体异常高风险者11例,其中,21-三体6例,18-三体3例,13-三体2例;性染色体异常(45,XO;47,XXX)2例。NIPT检测阳性率为2.21%(13/587)。13例高风险孕妇行羊水染色体核型结果显示,21-三体6例,18-三体2例,13-三体1例,性染色体异常2例。应用NIPT后介入性产前诊断率为1.87%;其中21-三体阳性预测值为100.00%(6/6),18-三体阳性预测值为66.67%(2/3),13-三体阳性预测值为50.00%(1/2),性染色体阳性预测值为100.00%(2/2)。35～39岁年龄组染色体异常高风险发生率为1.18%(5/425),年龄≥40岁组染色体异常高风险发生率为4.94%(8/162),两组比较,差异有统计学意义(P<0.05)。结论 NIPT检测对高龄孕妇胎儿21-三体、18-三体及性染色体符合率较高,可明显减少高龄孕妇介入性产前诊断,提高产前筛查的准确性。     

胎儿超声软指标及结构异常在胎儿染色体异常产前诊断中临床价值

目的 探讨胎儿超声软指标及结构异常在胎儿染色体异常产前诊断中的临床价值。方法 选取百色市妇幼保健院产前诊断中心自2020年2月至2022年11月收治的孕育具有超声软指标或结构异常胎儿的283例孕妇为研究对象。所有胎儿均接受介入性染色体筛查,分析不同超声软指标和结构异常胎儿的染色体异常情况,采用多因素Logistic回归分析影响胎儿染色体异常的相关因素。结果 283例孕妇中：单项超声软指标异常249例(87.98%),2项软指标异常29例(10.25%),3项及以上软指标异常5例(1.77%);单项结构异常96例(33.92%),2项结构异常19例(6.71%),3项及以上结构异常2例(0.71%)。超声软指标异常胎儿的染色体异常检出率依次为鼻骨发育异常(16.39%)、侧脑室增宽(13.43%)、NT增厚(12.36%)、脉络丛囊肿(11.76%)、单脐动脉(11.53%)、长骨短小(10.00%)、心室强光点(8.70%)、肾盂分离(4.17%),肠管强回声胎儿未检出染色体异常。超声单项结构异常胎儿的染色体异常检出率依次为颈部水囊瘤(25.00%)、心脏系统(19.23%)、神经系统...     

Agenesis of the corpus callosum in fetuses with mild ventriculomegaly: role of MR imaging

Purpose

We evaluated the role of magnetic resonance (MR) imaging in the diagnosis of corpus callosum agenesis — isolated or associated with other anomalies — in fetuses with mild cerebral ventriculomegaly, as depicted at prenatal sonography.

Material and methods

Between January 2005 and March 2007, 33 fetuses with a mean gestational age of 28.9 weeks (range 17–37) and mild ventriculomegaly diagnosed at prenatal sonography were included in this prospective study. All fetuses underwent MR imaging according to the following protocol: half-Fourier T2-weighted images along the three orthogonal plane according to the longitudinal axis of the mother, and subsequently three orthogonal planes were acquired according to the fetal brain. Quantitative image analysis included the size of the transverse diameter of the lateral ventricles, in the axial plane, and the thickness of the adjacent cerebral cortex. Qualitative image analysis included morphology of the lateral ventricles (normal, parallel pattern colpocephaly), signal intensity changes of the fetal brain, interruption of the germinative matrix, agenesis of the corpus callosum (complete/partial) and associated malformations. Postnatal physical examination and diagnostic imaging, as well as surgery, were the standard of diagnosis.

Results

Mean axial diameter of the lateral ventricle was 11.6 mm (range 10–15 mm), and mean thickness of the adjacent cerebral cortex was 2.1 mm (range 1.8–3 mm); 23/33 fetuses (70%) showed normal morphology of the lateral ventricles, and 8/33 (24%) showed abnormal morphology (parallel pattern, colpocephaly). The entire corpus callosum was visualised in 20/33 fetuses (60%). In 8/33 fetuses (25%), partial agenesis was diagnosed, whereas in 5/33 (15%), there was hypogenesis. In 6/13 fetuses (46%), isolated corpus callosum agenesis was detected, and two cases of hypogenesis of the corpus callosum were misinterpreted — overestimated in one case and underestimated in another.

Conclusions

MR imaging may prove to be a useful second-line imaging modality in the prenatal diagnosis of corpus callosum agenesis in fetuses with mild ventriculomegaly.     

Effacement of the fetal cisterna magna in association with myelomeningocele

The cisterna magna is effaced in association with myelomeningocele. The authors retrospectively investigated the size of the fetal cisterna magna as a predictor of fetal myelomeningocele in 67 pregnant women (17-38 menstrual weeks) referred for prenatal sonography because of an elevated serum alpha-fetoprotein level (n = 61) or a suspicion of fetal ventriculomegaly on previously obtained sonograms (n = 6). Twenty fetuses had myelomeningocele, 14 had isolated ventriculomegaly, and 33 were normal. A normal-sized cisterna magna (range, 4-9 mm in depth) was present in all normal fetuses. In 19 of 20 fetuses with myelomeningocele, the views of the posterior fossa were adequate, and in each of these the cisterna magna was effaced (n = 18) or very small (n = 1). The cisterna magna was effaced in five of 13 (38%) fetuses with isolated ventriculomegaly in whom the posterior fossa was adequately imaged. Although effacement of the cisterna magna is a nonspecific finding, the high negative predictive value of this sign is useful during routine screening of the fetal neural axis.     

Mild lateral cerebral ventricular dilatation in utero: clinical significance and prognosis

The medical records of 55 fetuses with sonographically diagnosed mild ventriculomegaly (MVM) were reviewed to assess prognosis. Fetuses were divided into two groups based on the presence or absence of sonographically detected associated fetal anomalies: 13 had no other anomalies detected (isolated MVM), and 42 had concomitant neural axis and visceral anomalies (nonisolated MVM). Mortality was 83% among fetuses with nonisolated MVM and 38% among fetuses with isolated MVM (P less than .005). If terminated pregnancies are excluded, only one of nine (11%) fetuses with isolated MVM died, compared with nine of 16 (56%) fetuses with nonisolated MVM (P less than .005). There are 15 living children: Nine (60%) are developmentally normal at 6-30 months of follow-up (six had isolated MVM), three (20%) are or are likely to be abnormal, and we were unable to follow up three (20%). Fetal anomalies were missed in 11 of 30 (37%) fetuses with detailed follow-up. However, this would have changed the classification from isolated to nonisolated MVM in only one case. Thus, in 54 of 55 cases (or 29 of 30 cases with detailed follow-up), fetuses were accurately classified as having isolated or nonisolated MVM. The authors conclude that sonographically isolated MVM is associated with a significantly better prognosis than nonisolated MVM, and fetuses can be classified accurately based on prenatal sonograms.     

Role of fetal MRI in the diagnosis of cerebral ventriculomegaly assessed by ultrasonography

Purpose

To evaluate the additional diagnostic value of fetal MRI to evaluate cerebral ventriculomegaly assessed by ultrasonography (US) for the possibility to change the diagnosis, the counseling and the management of pregnancy.

Materials and Methods

From february 2006 to october 2008, we studied 55 pregnant women by fetal MRI (mean age 28 years), 4 with twin pregnancy, for a total of 59 fetuses with mean gestational age of 27 weeks. The number of fetuses affected by ventriculomegaly assessed by US was 55. All fetuses had a US diagnosis of ventriculomegaly: 29 fetuses with isolated ventriculomegaly and 26 fetuses with ventriculomegaly associated with CNS (central nervous system) abnormalities (18) and with no CNS abnormalities (8).

Results

The findings showed that the two techniques are substantially in agreement in defining the degree of VM, with the exception of some cases in which the disagreement could be attributed to the possible progression of the dilatation between the US and MRI examinations, which sway between two days and two weeks. We proved a low correlation between US and MRI in the evaluation of ventriculomegaly associated either with CNS or non-CNS anomalies: in fact while fetal MRI detected 26/55 (47,3%) VM associated with CNS anomalies, US demonstrated only 18/55(32,7%). Referring to VM associated with non-CNS anomalies, MRI diagnosed 10/55 cases (18,2%) compared to 8/55 fetuses (14,5%) showed by US.

Conclusions

Our experience demonstrated that fetal MRI has an important role as adjunctive tool to sonography in the evaluation of cerebral ventriculomegaly for the additional informations given to parents and for the possibility to change the diagnosis, the counseling and the management of pregnancy.     

Sonography of facial features of alobar and semilobar holoprosencephaly

Twenty-seven cases of alobar/semilobar holoprosencephaly were reviewed to determine and classify the associated facial abnormalities detected with prenatal sonography. All but one case were diagnosed prospectively with sonography. Facial abnormalities were present in 24 of 27 cases and were detected in 14 (58%) of 24 fetuses on prenatal sonography. Prenatal abnormalities detected by sonography included cyclopia (four of five), ethmocephaly (two of three), cebocephaly (one of three), midline cleft lip (four of eight), lateral cleft lip (two of two), and mild hypotelorism (one of three). One or more extrafacial anomalies were present in 14 (52%) of 27 fetuses. Other major structural anomalies detected prenatally by sonography included meningomyelocele (two of two), renal dysplasia (five of six), omphalocele (three of four), esophageal atresia (zero of three), and cardiac defects (one of seven). Chromosomal analysis revealed abnormal karyotype in 13 (50%) of the 26 fetuses in which it was performed; the most common abnormality was trisomy 13 (seven cases). The perinatal mortality rate was 89% (24 of 27); three neonates with holoprosencephaly were alive when discharged from the hospital. It is concluded that when a major cystic abnormality of the fetal brain is detected, prenatal sonographic analysis of midline facial defect may allow more definitive diagnosis of alobar or semilobar holoprosencephaly; affected fetuses often have other major structural abnormalities, and the outcome is nearly always fatal.     

孤立性侧脑室扩张胎儿脑的MRI弥散加权成像评估

目的:探讨ADC值对胎儿侧脑室扩张的诊断价值。方法:对50例轻度孤立性侧脑室扩张胎儿(轻度扩张组)及50例重度孤立性侧脑室扩张的胎儿(重度扩张组)行DWI扫描,分别测量胎脑双侧额叶、顶叶、颞叶、枕叶白质、基底核、丘脑及小脑ADC值,比较两组各脑区ADC值差异及各个侧脑室扩张胎儿左侧及右侧各脑区ADC值的差异。结果:与轻度扩张组比较,重度扩张组双侧额叶、顶叶,枕叶白质及基底核ADC值下降(P均<0.05)。侧脑室扩张胎儿左侧与右侧各脑区ADC值差异均无统计学意义(P均>0.05)。结论:重度侧脑室扩张胎儿额叶、顶叶,枕叶,基底节ADC值下降,ADC值对检测潜在脑部损伤较敏感,有助于评估胎儿孤立性侧脑室扩张神经系统改变。     

Simple screening method for copy number variations associated with physical features

Recent studies of copy number variations (CNVs) associated with physical features, such as body mass index, body height or bone length, have suggested that such CNVs could serve as markers in forensic cases involving unidentified individuals. However, the process of cataloging CNVs has been slow because of the cumbersome nature and low reliability of the procedures involved. Here we describe a simple quantitative real-time PCR (Q-PCR) method for screening of medicolegally useful CNVs, which does not require reference DNA with known copy number. The first step is to prepare a chimeric plasmid vector including one copy each of the single-copy gene-specific sequence as the internal standard, and the target CNV-specific sequence. To assess the validity of this new method, we analyzed CNVs in the LTBP1 and ETV6 gene regions, both of which are candidate CNVs associated with body height. The PCR efficiencies for the single-copy (reference) gene and the target CNV were similar, indicating that quantitation was reliable. Furthermore, simulated analysis of the LTBP1 CNV using mock samples prepared by mixing vectors in varying proportions showed that this analytical method allowed correct determination of the LTBP1 copy number. These results demonstrated that our simple method has considerable potential for screening of trait-related CNVs that would be useful for forensic casework.     

Fetal diffusion tensor quantification of brainstem pathology in Chiari II malformation

Objectives

This prenatal MRI study evaluated the potential of diffusion tensor imaging (DTI) metrics to identify changes in the midbrain of fetuses with Chiari II malformations compared to fetuses with mild ventriculomegaly, hydrocephalus and normal CNS development.

Methods

Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were calculated from a region of interest (ROI) in the midbrain of 46 fetuses with normal CNS, 15 with Chiari II malformations, eight with hydrocephalus and 12 with mild ventriculomegaly. Fetuses with different diagnoses were compared group-wise after age-matching. Axial T2W-FSE sequences and single-shot echo planar DTI sequences (16 non-collinear diffusion gradient-encoding directions, b-values of 0 and 700 s/mm², 1.5 Tesla) were evaluated retrospectively.

Results

In Chiari II malformations, FA was significantly higher than in age-matched fetuses with a normal CNS (p?=?.003), while ADC was not significantly different. No differences in DTI metrics between normal controls and fetuses with hydrocephalus or vetriculomegaly were detected.

Conclusions

DTI can detect and quantify parenchymal alterations of the fetal midbrain in Chiari II malformations. Therefore, in cases of enlarged fetal ventricles, FA of the fetal midbrain may contribute to the differentiation between Chiari II malformation and other entities.

Key Points

? FA in the fetal midbrain is elevated in Chiari II malformations. ? FA is not elevated in hydrocephalus and mild ventriculomegaly without Chiari II. ? Measuring FA may help distinguish different causes for enlarged ventricles prenatally. ? Elevated FA may aid in the diagnosis of open neural tube defects. ? Elevated FA might contribute to stratification for prenatal surgery in Chiari II.