先天性疾病研究及产前诊断中Array CGH的应用

染色体微缺失、重复、扩增和非整倍体等基因组DNA失衡是导致胎儿发育迟缓、畸形、死胎、流产和其他先天性疾病的内在原因。微阵列-比较基因组杂交技术（Array CGH）利用基因芯片取代了传统比较基因组杂交技术的正常中期染色体作为杂交靶标,与分别采用不同荧光标记的待测DNA和参照DNA杂交,通过比较两种荧光强度的比率,检测出染色体基因拷贝数变化。Array CGH已成为一个重要的细胞遗传学研究工具,用于产前诊断和先天性疾病诊断染色体亚显微结构异常。     

荧光原位杂交技术的妇产科应用进展

荧光原位杂交(FISH)技术是一门新兴的分子细胞学遗传技术,具有快速、安全、简便、高灵敏度、高特异性及多色等优点.已经广泛应用于分子细胞遗传学检测、间期细胞遗传学分析以及DNA片段的染色体定位等研究中,推动了临床细胞遗传学的发展.随着细胞遗传学研究技术的不断深入,在FSH技术上建立了比较基因组杂交技术(CGH)、微阵列比较基因组杂交技术(array CGH).目前FISH技术在产前诊断、植入前遗传学诊断、妇科肿瘤相关基因诊断和分析中展现出更加广阔的应用前景.从FISH技术探针的类型、标记方法及在妇产科领域的应用做简要综述.     

唐氏综合征的产前诊断分子技术研究进展

唐氏综合征是人类常见的染色体疾病,经典的细胞遗传学方法是诊断唐氏综合征的金标准,但其局限性不适合大规模的产前诊断.随着分子细胞遗传学技术发展,荧光原位杂交技术(FISH)、定量荧光PCR(QF-PCR)、微阵列-比较基因组杂交(Array CGH)、多重连接探针扩增技术(MLPA)、引物原位标记技术(PRINS)等被用于唐氏综合征快速产前诊断,各种方法各有优劣,改进后会大力推进唐氏综合征的产前诊断速度和准确性.     

两种不同遗传学分析方法用于诊断自然流产组织的比较

目的探讨比较基因组杂交（CGH）技术与绒毛细胞培养染色体核型分析用于自然流产组织遗传学诊断的准确性。方法选择妊娠49—91d的自然流产患者38例,在无菌条件下经宫颈取绒毛,其中难免流产的新鲜组织标本27份,过期流产的陈旧组织标本11份。每份组织标本均采用绒毛细胞培养染色体核型分析,并同时采用CGH技术对全基因组进行分析。结果CGH技术诊断成功率为100％（38／38）,而绒毛细胞培养染色体核型分析诊断成功率为82％（31／38）。两种方法的诊断符合率为90％（28／31）,在3例出现不同诊断结果的病例中,1例绒毛细胞培养染色体核型分析显示染色体核型正常,而CGH技术显示3q^22_q^24缺失;另2例绒毛细胞培养染色体核型分析为3倍体,但CGH技术诊断结果显示正常。在7例绒毛细胞培养失败而仅有CGH技术诊断结果者中,3例为染色体非整倍体异常,另4例正常。结论CGH技术用于诊断自然流产组织是可行的。绒毛细胞培养染色体核型分析比较,CGH技术诊断成功率高,且对非平衡染色体结构重排的诊断有较高的敏感性,可以作为绒毛细胞培养染色体核型分析的补充方法。     

唐氏综合征的产前诊断分子技术研究进展

唐氏综合征是人类常见的染色体疾病，经典的细胞遗传学方法是诊断唐氏综合征的金标准，但其局限性不适合大规模的产前诊断。随着分子细胞遗传学技术发展，荧光原位杂交技术（FISH）、定量荧光PCR（QF-PCR）、微阵列-比较基因组杂交（Array CGH）、多重连接探针扩增技术（MIJPA）、引物原位标记技术（PRINs）等被用于唐氏综合征快速产前诊断，各种方法各有优劣，改进后会大力推进唐氏综合征的产前诊断速度和准确性。     

荧光原位杂交技术的妇产科应用进展

荧光原位杂交（FISH）技术是一门新兴的分子细胞学遗传技术,具有快速、安全、简便、高灵敏度、高特异性及多色等优点,已经广泛应用于分子细胞遗传学检测、间期细胞遗传学分析以及DNA片段的染色体定位等研究中。推动了临床细胞遗传学的发展。随着细胞遗传学研究技术的不断深入,在FISH技术上建立了比较基因组杂交技术（CGH）、微阵列比较基因组杂交技术（arrayCGH）。目前FISH技术在产前诊断、植入前遗传学诊断、妇科肿瘤相关基因诊断和分析中展现出更加广阔的应用前景。从FISH技术探针的类型、标记方法及在妇产科领域的应用做简要综述。     

简并寡核苷酸引物聚合酶链反应扩增单细胞全基因组均匀性研究

目的　探讨单细胞简并寡核苷酸引物聚合酶链反应 (DOP PCR)扩增全基因组DNA的均匀性及植入前胚胎遗传学研究的新途径。方法　获取正常男女性、X单体、X、13和 2 1三体细胞 ,行单细胞DOP PCR ,通过比较基因组杂交 (CGH )双色荧光强度比变化 ,分析扩增均匀性。结果　 (1)DOP PCR产物 /正常男性基因组DNACGH :约 1/ 3常染色质区强度比均数及标准差超过正常允许范围 ,X染色体假性过度表达 ,13、2 1三体无明显变化。 (2 )DOP PCR产物 /正常男性单细胞DOP PCR产物CGH :94%强度比均数及标准差接近期望值 ,能显示正常男女性、X单体、X、13和 2 1三体染色体拷贝数变化。结论　单细胞DOP PCR扩增基因组DNA存在明显的不均匀性 ,但这种不均匀扩增是非随机的。如选择合适的参照 ,扩增产物可用于植入前胚胎等单细胞全基因组研究。     

分子细胞遗传学技术应用于产前诊断的新进展

在过去的10年中,临床细胞遗传学有了显著的进步,分子生物技术被应用到了常规染色体分析。这些新技术的应用解决了传统核型显带分析在准确诊断和解释某些染色体的技术上的缺陷,这些新技术包了荧光原位杂交(fluorescence in situ hybridization,FISH)、多色荧光原位杂交(Multicolor-fluorescence in situ hybridization,M-FISH)、光谱核型分析(Spectral karyotyping,SKY)、比较基因组杂交(comparative genomic hybridization,CGH)和微阵列基因组杂交(array comparative genomic hybridization,aCGH)。每1种技术都有特定的检测范围与限制。本文对这些技术的特点及它们的在产前诊断的应用综述。     

不同分子遗传学方法用于自然流产绒毛细胞遗传分析的效果

目的 探讨多重连接探针扩增法(MLPA)+荧光原位杂交(FISH)和比较基因组杂交(CGH)+FISH的分子遗传学方法用于自然流产绒毛细胞遗传分析的效果.方法 收集29例自然流产绒毛组织以及6例选择性终止早期妊娠妇女的绒毛组织,采用CGH+FISH、MLPA+FISH方法进行遗传学分析,并与传统的绒毛细胞培养染色体核型分析结果进行比较.结果 MLPA+FISH检测时间为40 h,CGH+FISH检测时问为120 h,绒毛细胞培养染色体核型分析时间为(240±72)h,3者分别比较,差异有统计学意义(P<0.01).CGH、MLPA、FISH和绒毛细胞培养染色体核型分析的标本成功获检率分别为97%(34/35)、100%(35/35)、100%(35/35)和91%(32/35),4者比较,差异无统计学意义(P>0.01).除去CGH获检失败的1份样本外,MLPA+FISH与CGH+FISH的分析结果一致,CGH获检失败的1例标本经MLPA+FISH检测获得了结果.CGH+FISH或MLPA+FISH检测结果与绒毛细胞培养染色体核型分析结果的不一致率分别为13%(4/31)、12%(4/32),两者比较,差异无统计学意义(P>0.05).结论 MLPA+FISH检测耗时短,检测成功率高;MLPA+FISH检测用于自然流产绒毛细胞遗传分析是对绒毛细胞培养染色体核型分析方法的重要补充.     

卵巢癌紫杉醇耐药细胞株OC_3/PIX_3及OC_3/PIX_5的比较基因组杂交研究

目的:了解两种卵巢癌紫杉醇耐药株(OC3/PIX3及OC3/PIX5)和其亲代细胞紫杉醇敏感株(OC3)染色体DNA拷贝数的差异变化,探讨耐药细胞的分子遗传学改变。方法:运用比较基因组杂交(comparative genom ic hybrid ization,CGH)技术,将OC3/PIX3及OC3/PIX5与其亲代细胞株OC3的染色体基因组进行比较分析。结果:3种细胞株的染色体2pter-p21、3q、5p、9均有遗传物质表达增加;10号染色体表达增加仅见于OC3。染色体1,4,6的遗传物质在3种细胞株的表达均有减少。3p的减少发生在OC3和OC3/PIX5。仅在OC3细胞中见到7q、8p减少。OC3和OC3/PIX5出现染色体10q22过度扩增。最有意义的变化是OC3/PIX3细胞染色体2p22的过度扩增。结论:2p22拷贝数过度扩增可能与卵巢癌紫杉醇耐药相关。     

Analyse chromosomique sur puce à ADN (CGH array) : principe et application en diagnostic prénatal

Array CGH is a new automated exploration method that overcomes cell cultures, and his resolution power is 10 to 1000 times higher than the karyotype one??s. In postnatal diagnosis, the study by array CGH of patients with intellectual disabilities and/or congenital malformations led to the identification of about 10% to 15% of chromosomal anomalies that are not visible on the karyotype. Thus, array CGH has become the first-line test for genomic analysis of these patients. The application of array CGH in prenatal diagnosis is more difficult because of the detection of chromosomal anomalies whose clinical impact is difficult to predict. However, advances in knowledge of the genome and the development of appropriate tools (DNA chips) will allow to consider, in the future, the application of this technique as first-line test for the study of chromosomes in prenatal diagnosis.     

Microphthalmia with linear skin defects (MLS) syndrome evaluated by prenatal karyotyping, FISH and array comparative genomic hybridization

OBJECTIVE: To explore the utility of comparative genomic hybridization to BAC arrays (array CGH) for prenatal diagnosis of microphthalmia and linear skin defects syndrome. METHODS: We used karyotype analysis, FISH and array CGH to investigate an X;Y translocation. Replication studies were done on cultured amniocytes and lymphoblasts. RESULTS: We describe a severe case of MLS syndrome that presented prenatally with multiple anomalies including cystic hygroma, microphthalmia, intrauterine growth restriction and a complex congenital heart defect. Cytogenetic analysis of amniocytes revealed an unbalanced de novo translocation between chromosomes X and Y [karyotype 46,X,der(X)t(X;Y)(p22.3;q11.2).ish der(X)(DXZ1+,DMD+,KAL-,STS-,SRY-),22q11.2 (Tuple1 x 2)]. MLS diagnosis was made at birth and the prenatal karyotype was confirmed. Replication studies showed the derivative X chromosome was the inactive X. Array CGH confirmed the X and Y imbalances seen in the karyotype and also showed twelve BACs in the MLS region were deleted as a result of the translocation. FISH with BAC clones verified the array findings and placed the X breakpoint in Xp22.2, resulting in the amended karyotype, 46,X,der(X)t(X;Y)(p22.2;q11.2).ish der(X)(DXZ1+,DMD+,KAL-,STS-,SRY-),22q11.2(Tuple1 x 2) arr cgh Xp22.33p22.2(LLNOYCO3M15D10 -->GS1-590J6)x 1,Yq11.222q23(RP11-20H21-->RP11-79J10)x 1. CONCLUSION: The sensitivity of array CGH was valuable in detecting monosomy of the MLS critical region. Array CGH should be considered for the prenatal diagnosis of this syndrome.     

Detection of numerical chromosome aberrations by comparative genomic hybridization

At least 50 per cent of all first-trimester spontaneous abortions are cytogenetically abnormal, including trisomy, monosomy X, triploidy, tetraploidy and structural chromosome anomalies. Traditionally, the detection of aneuploidy in fetal tissues is performed by tissue sampling, cell culturing, metaphase spread preparation, and conventional banding analyses. This is a tedious, laborious and time-consuming process, prone to errors due to external contamination, culture failure and selective growth of maternal cells. In the present study, we applied the CGH technique in the detection of numerical chromosome abnormalities in 50 placentae of spontaneously aborted fetuses. CGH detected six different types of trisomy (trisomy 8, 15, 16, 18, 22 and 21), one double trisomy (involving chromosomes 14 and 21), and one monosomy X. Overall, nine samples (18 per cent) harboured numerical chromosome aberrations. Aneuploidy was detected in eight samples by CGH and in six samples by conventional cytogenetic analysis. In only one case, CGH failed to detect a mosaic for trisomy revealed by conventional cytogenetic analysis. The successful application of the CGH technique to the detection of aneuploidy in spontaneous abortions, demonstrates the utility of using this technique to screen prenatally for numerical chromosome abnormalities. Our preliminary data support the application of CGH to the clinical genetics setting, at least as a complementary tool to the traditional cytogenetic techniques.     

Array comparative genomic hybridization profiling of first-trimester spontaneous abortions that fail to grow in vitro

OBJECTIVES: Cytogenetic analysis of spontaneous abortion samples can be limited by culture failure. Failure to grow in vitro has traditionally been suspected to be due to in vivo death of tissue associated with spontaneous abortion (SAB) or simply technical factors of growth in culture. METHOD: We used array comparative genomic hybridization (array CGH) to investigate chromosomal imbalances in products of conception that failed to grow in vitro. RESULTS: Our data on 26 cases of SABs that failed to grow in culture are compared and contrasted with published data on cytogenetic findings following in vitro culture. The results revealed abnormalities uncommonly seen by classic cytogenetic methods. These abnormalities include high rates of double aneuploidy and autosomal monosomy. The data taken together suggest that classic cytogenetics of spontaneous abortion may yield normal karyotypes or selected abnormal karyotypes that permit cell proliferation in vitro while Array CGH detects other abnormalities. CONCLUSION: Array CGH is becoming an important clinical assay for unbalanced chromosome abnormalities whether cells grow in culture or not and in cases of analysis on one or few cells.     

Prenatal and postnatal characterization of Y chromosome structural anomalies by molecular cytogenetic analysis

We describe three cases in which we used fluorescence in situ hybridization (FISH), polymerase chain reaction (PCR) and comparative genomic hybridization (CGH) to characterize Y chromosome structural anomalies, unidentifiable by conventional G-banding. Case 1 was a 46,X,+mar karyotype; FISH analysis revealed an entire marker chromosome highlighted after hybridization with the Y chromosome painting probe. The PCR study showed the presence of Y chromosome markers AMG and SY620 and the absence of SY143, SY254 and SY147. CGH results confirmed the loss of Yq11.2-qter. These results indicated the presence of a deletion: del(Y)(q11.2). Case 2 was a 45,X [14]/46,XY[86] karyotype with a very small Y chromosome. The PCR study showed the presence of Y chromosome markers SY620 and AMG, and the absence of SY143, SY254 and SY147. CGH results showed gain of Yq11.2-pter and loss of Yq11.2-q12. These results show the presence of a Yp isodicentric: idic(Y)(q11.2). Case 3 was a 45,X,inv(9)(p11q12)[30]/46,X,idic(Y)(p11.3?),inv(9)(p11q12)[70] karyotype. The FISH signal covered all the abnormal Y chromosome using a Y chromosome paint. The PCR study showed the presence of Y chromosome markers AMG, SY620, SY143, SY254 and SY147. CGH only showed gain of Yq11.2-qter. These results support the presence of an unbalanced (Y;Y) translocation. Our results show that the combined use of molecular and classical cytogenetic methods in clinical diagnosis may allow a better delineation of the chromosome regions implicated in specific clinical disorders.     

De novo 16p13.11 microdeletion identified by high-resolution array CGH in a fetus with increased nuchal translucency

Objective  We investigated the application of high-resolution microarray-based comparative genomic hybridisation (array CGH) on a fetus showing increased nuchal translucency (NT).
Design  Case study.
Setting  Tertiary referral obstetrics unit.
Sample  Pregnant woman attended the antenatal clinic.
Methods  Conventional karyotyping and genetic test was carried out for the alpha-globin gene. High-resolution array CGH using the high-density 244K Agilent microarray was performed on fetal blood sample by cordocentesis to investigate the possibility of any genomic imbalance.
Main outcome measures  Detection of chromosomal abnormality.
Results  Karyotyping analysis showed 46,XY. Molecular genetic diagnosis confirms the fetus has Hb-H constant spring disease but cannot explain the increased NT to 3.2 mm. Array CGH analysis discovered a 1.32-Mb microdeletion on chromosome 16p13.11. Deletion at 16p13.11 has been implicated to predispose to autism and/or mental retardation. Baby was delivered at 40 weeks of gestation, and follow up was carried out at 3 months of age without sign of mental retardation/developmental delay.
Conclusions  This case study demonstrated that array CGH can accurately calibrate the size and identify de novo interstitial chromosome imbalances. However, the presence of chromosome copy variants with unknown clinical significance currently limits its wider scale application in prenatal diagnosis and needs further investigations.     

Cytogenetic analysis of trophoblasts by comparative genomic hybridization in embryo-fetal development anomalies

Cytogenetic studies of spontaneous abortions or intrauterine fetal death depend on conventional tissue culturing and karyotyping. This technique has limitations such as culture failure and selective growth of maternal cells. Fluorescent in situ hybridization (FISH) using specific probes permits diagnosis of aneuploidies but is limited to one or a few chromosomal regions. Comparative genomic hybridization (CGH) provides an overview of chromosomal gains and losses in a single hybridization directly from DNA samples. In a prospective study, we analyzed by CGH trophoblast cells from 21 fetuses in cases of spontaneous abortions, intrauterine fetal death or polymalformed syndrome. Six numerical chromosomal abnormalities including one trisomy 7, one trisomy 10, three trisomies 18, one trisomy 21 and one monosomy X have been correctly identified by CGH. One structural abnormality of the long arm of chromosome 1 has been characterized by CGH. One triploidy and two balanced pericentromeric inversions of chromosome 9 have not been identified by CGH. Sexual chromosomal constitutions were concordant by both classical cytogenetic technique and CGH. Contribution of trophoblast analysis by CGH in embryo-fetal development anomalies is discussed.     

A dysmorphic newborn infant with a complex rearrangement involving chromosomes 2, 4, and 6 detected by fluorescence in situ hybridization (FISH)

A newborn female infant with multiple congenital anomalies was found to have an unusual and abnormal karyotype. Cytogenetic studies revealed an apparent balanced translocation between chromosome 4q31.3 and chromosome 6q25.1. Additional material on chromosome 2p was identified and determined to be from chromosome 6q by analysis with fluorescence in situ hybridization (FISH). The karyotype is 46,XX,der(2)t(2;6)(p23;q25.1), t(4;6)(q31.3;q25.1). Her mother has a normal female karyotype. The father was unavailable for physical examination or cytogenetic analysis.     

Analysis of uncultured amniocytes by comparative genomic hybridization: a prospective prenatal study

Comparative genomic hybridization (CGH) is a new molecular cytogenetic technique which can detect and map whole and partial aneuploidies throughout a genomic specimen DNA without culturing specimen cells. Thus, CGH may be used as a comprehensive and rapid screening test in prenatal unbalanced chromosomal abnormalities detection. We report the results of the first prospective study to evaluate the use of the CGH technique on uncultured amniocytes. Seventy-one amniotic fluid samples, obtained by transabdominal amniocentesis between the 14th and 35th weeks of gestation, were simultaneously investigated using CGH and conventional cytogenetics. Amniocentesis were done for advanced maternal age (21.1%), fetal ultrasound anomalies (73.3%) and high level of biochemical markers in maternal serum (5.6%). Sixty-six (93%) informative results were generated on a total of 71 analysed specimens. Fifty-nine samples were reported as disomic for all autosomes with a normal sex chromosome constitution using CGH and conventional cytogenetics. Among them, three pericentromeric chromosomal inversions were undetected by CGH analysis. Seven numerical aberrations were characterized, including one case of trisomy 13, one case of trisomy 18 and five cases of trisomy 21. Advantages and limitations of CGH for a rapid prenatal screening of unbalanced chromosomal aberrations are discussed.