微阵列比较基因组杂交技术检测先天性心脏畸形胎儿的隐藏基因组拷贝数变异

目的 检测1例先天性主动脉弓离断和室间隔缺损胎儿的基因组拷贝数变异(copy number variations,CNVs),寻找其致病的遗传学证据,探讨微阵列比较基因组杂交技术(array-based comparative genomic hybridization,array-CGH)在分子细胞遗传诊断中应用的可行性.方法 对该患儿脐血及其父母外周血进行常规G显带核型分析,发现胎儿核型为46,XX,t(7;9)(q12;q21),双亲核型正常.进而应用array-CGH芯片对患儿进行全基因组高分辨率扫描分析,采用荧光原位杂交技术(fluorescence in situ hybridization,FISH)对新发现的CNVs进行实验验证.结果 array-CGH分析发现胎儿基因组存在1个病理性亚显微结构的拷贝数变异:del(22)(q11.2)(17 370 128～19 790 009,2.42 Mb).FISH实验结果验证了此22q11.2微缺失的存在.结论 隐藏的22q11.2微缺失可能是此胎儿致病的原因;染色体平衡易位的先天缺陷胎儿可能会含有位于重排断裂点区域之外的亚显微结构基因组拷贝数变异;微阵列比较基因组杂交具有高分辨率、高通量和高准确性等优点,适用于亚显微基因组拷贝数变异的检测.

Abstract：

Objective To detect the copy number variation (CNV) of a fetus with interrupted aortic arch and ventricular septal defect, in order to explore the underlying genetic causes of the congenital malformation, and investigate the feasibility of array-based comparative genomic hybridization (array-CGH)in molecular cytogenetic diagnosis. Methods The whole genome of the fetus with de novo apparently balanced translocations [46, XX, t ( 7 ; 9 ) ( q12 ; q21 ) ] diagnosed by G-banding was scanned and analyzed by array-CGH, and the copy number variation was confirmed by fluorescence in situ hybridization (FISH).Results A pathologic submicroscopic CNV ldel(22) (q11. 2) (17 370 128-19 790 009,-2. 42 Mb)] was identified and mapped by array-CGH. FISH test confirmed the microdeletion detected by array-CGH.Conclusion The cryptic 22q11.2 deletion might be the reason leading to the congenital malformation of the fetus. This study provides evidence that apparently balanced translocations classified by conventional cytogenetic techniques may host additional submicroscopic CNVs which are not located at the breakpoints.Due to the high-resolution, high-throughput and high-accuracy, array-CGH is considered to be a powerful tool for submicroscopic CNVs detection.     

微阵列比较基因组杂交技术检测先天性心脏畸形胎儿的隐藏基因组拷贝数变异

目的 检测1例先天性主动脉弓离断和室间隔缺损胎儿的基因组拷贝数变异(copy number variations,CNVs),寻找其致病的遗传学证据,探讨微阵列比较基因组杂交技术(array-based comparative genomic hybridization,array-CGH)在分子细胞遗传诊断中应用的可行性.方法 对该患儿脐血及其父母外周血进行常规G显带核型分析,发现胎儿核型为46,XX,t(7;9)(q12;q21),双亲核型正常.进而应用array-CGH芯片对患儿进行全基因组高分辨率扫描分析,采用荧光原位杂交技术(fluorescence in situ hybridization,FISH)对新发现的CNVs进行实验验证.结果 array-CGH分析发现胎儿基因组存在1个病理性亚显微结构的拷贝数变异:del(22)(q11.2)(17 370 128～19 790 009,2.42 Mb).FISH实验结果验证了此22q11.2微缺失的存在.结论 隐藏的22q11.2微缺失可能是此胎儿致病的原因;染色体平衡易位的先天缺陷胎儿可能会含有位于重排断裂点区域之外的亚显微结构基因组拷贝数变异;微阵列比较基因组杂交具有高分辨率、高通量和高准确性等优点,适用于亚显微基因组拷贝数变异的检测.     

微阵列比较基因组杂交检测一例左心发育不良胎儿的基因组拷贝数变异

目的 检测1例左心发育不良胎儿的基因组拷贝数变异(copy number variations,CNVs),寻找可能的遗传学病因,并探讨微阵列比较基因组杂交(array-based comparative genomic hybridization,array-CGH)在分子细胞遗传学诊断方面的优越性.方法 对胎儿羊水细胞及其父母的外周血细胞进行常规G显带核型分析.用array-CGH芯片对胎儿进行高分辨率全基因组扫描分析,并用多重连接探针扩增技术(multiplex ligation-dependent probe amplification,MLPA)对新发现的CNVs进行验证.结果 胎儿羊水细胞及其父母的外周血细胞常规G显带核型分析未发现显著异常,Array-CGH结果发现胎儿基因组存在两个亚显微结构的拷贝数变异:del(11)(q24.1-ter)(121951443-134449216,-12.50 Mb),dup(15)(q26.3)(96889082-100215359,-3.33 Mb),MLPA结果验证了这两个基因组拷贝数变异的存在.结论 Del(11)(q24.1-ter)很可能是患儿左心发育不良的病因.array-CGH技术具有高分辨率、准确等优点,是临床遗传学的重要技术手段,有助于基因组异常的检测和临床遗传咨询.     

微阵列比较基因组杂交技术分析一例猫叫综合征患儿的基因组拷贝数变异

目的 对1例猫叫综合征患儿进行基因组拷贝数分析,寻找其致病原因.方法 对患儿外周血进行常规G显带分析,应用微阵列比较基因组杂交技术进行全基因组扫描,并应用荧光原位杂交技术对异常拷贝数区域进行验证.结果 患儿染色体核型为46,XY,der(5)(p?).微阵列比较基因组杂交显示其在5p14.2-p15.3处存在23.263Mb的片段缺失,12号染色体12p31区域存在14.602 Mb的片段重复.重复片段连接至5p14.2处,形成5号衍生染色体,即arr cgh 5p15.3p14.2(PLEKHG4B→CDH12)×1 pat,12p13.33p13.1(IQSEC3→GUC Y2C)× 3 pat.荧光原位杂交证实患儿存在5p末端缺失及12p末端重复.结论 5号染色体不平衡易位导致患儿5p末端缺失可能是患儿的病因.微阵列比较基因组杂交技术具有高分辨、高通量和高准确性的优点,适用于全基因组拷贝变异分析.     

微阵列基因组杂交技术在22q11．21微缺失家系中的应用研究

目的了解反复孕育严重先天性心脏病儿、胎儿父亲患有原发性甲状旁腺功能低下家系的基因组拷贝数变化,确定其发病的遗传学原因。方法对常规染色体核型分析未见异常的法洛氏四联症胎儿及其整个家系中的7人采用微阵列基因组杂交（array—based comparative genomic hybridization,array—CGH）技术进行基因组拷贝数变化的检测分析（copy number variations,CNVs）。结果经过array—CGH分析,在胎儿及其父亲的22q11．21均发现存在2．52Mb的致病性缺失片段,位于18,919,942—21,440,514区段。家系中其他成员未发现同样的片段异常。结论22q11．21微缺失是导致其父亲患原发性甲状旁腺功能减退的遗传学原因,也是该家系多次孕育严重先天性心脏病患儿的原因,同时表明22q11．21微缺失表型多样,临床症状差异大。array—CGH是一种高通量、高分辨率及高准确性的遗传学分析技术,能够发现染色体片段上的亚微结构异常,是临床遗传学研究的重要工具。     

用高分辨率微阵列比较基因组杂交分析一个孤独症家系的新生拷贝数变异

目的 对1个孤独症家系进行新发拷贝数变异(copy number variations,CNV)分析.方法 应用高分辨率全基因组芯片(Affymetrix Cytogenetics Whole-Genome 2.7M Array)检测该家系4名成员的基因组拷贝数,用Affymetrix Chromosome Analysis Suite软件分析结果.以基因组变异数据库亚洲正常人群及先证者父母、同胞为对照,分析先证者的新发CNV.结果 先证者存在89个新发拷贝数变异,其中5号、11号和14号染色体新发CNV总长占染色体全长超过1‰.3p26.1、4q22.2、5p15.2等区域也存在新发CNV,涉及GRM7、GRID2、CTNND2等10个与神经系统发育相关基因.结论 先证者多个与神经系统发育相关的基因存在新发拷贝数变异,这为探索孤独症的发病机理提供了新的线索.高分辨率基因组CNV芯片能够快速、准确地检测基因组的微小失衡,在遗传病诊断方面具有广阔的应用前景.     

微阵列比较基因组杂交技术及其应用

【摘要】基因组DNA拷贝数变化在许多人类疾病如肿瘤、遗传性疾病的发生发展中起重要作用。经典的比较基因组杂交技术由于分辨率低,只能检测较大的拷贝数变化。微阵列比较基因组杂交技术具有高分辨率、高灵敏度、高通量和自动化等优点,能准确检测单拷贝的缺失、复制和扩增,并把结果直接定位于基因组上,为肿瘤、遗传性疾病及正常人群基因组DNA拷贝数变化的研究提供了一种有效的方法。     

应用单核苷酸多态性-微阵列比较基因组杂交技术检测胎儿标记染色体

目的 探讨单核苷酸多态性-微阵列比较基因组杂交技术(single nucleotide polymorphism arraybased comparative genomic hybridization,SNP-array CGH)检测胎儿标记染色体及其在产前遗传学诊断中的应用.方法 应用SNP-array CGH技术对羊水G显带诊断出的两例携带标记染色体的胎儿(其中胎儿1核型为嵌合体47,XX,+mar[23]/46,XX[16]、胎儿2核型为47,XX,+mar),进行全基因组高分辨率扫描分析,确定标记染色体来源与片段大小;并用染色体末端探针多重连接依赖探针扩增技术(multiplex ligation-dependent probe amplification,MLPA)对胎儿2基因组不平衡进行验证.两例胎儿超声均无明显结构异常;两例胎儿的双亲核型均正常.结果 SNP-array CGH结果显示胎儿1标记染色体来源于9p21.1-p21.3(长度为8.3 Mb),显示嵌合型,根据文献推测此区带的重复携带者可以是表型正常(或有轻微异常)的个体.胎儿2标记染色体来源于15q11.2-q13.3(长度为10.8 Mb),染色体末端探针MLPA检测结果也证实了该重复的存在,此区域基因重复主要引起神经行为方面的异常.告知孕妇及家属风险,均选择终止妊娠.结论 SNP-array CGH技术能比其他技术更精确的确定标记染色体来源,可明确标记染色体的基因型,而且能检测出嵌合型的标记染色体,适用于产前遗传学诊断,并可为产前遗传咨询提供帮助.     

微阵列比较基因组杂交技术对一例胎儿染色体复杂易位的产前诊断

目的对1例5条染色体发生复杂易位的胎儿作出产前诊断,评价微阵列比较基因组杂交（array—CGH）技术在产前诊断中的应用价值。方法应用G显带分析羊水细胞染色体及夫妇双方外周血染色体,应用array—CGH技术对羊水细胞进行全基因组高分辨扫描分析,了解是否有微小缺失和重复。结果羊水细胞染色体结果为46,XX,t（5;7;12）,t（14;21）,夫妻双方外周血染色体核型正常,羊水细胞array—CGH结果显示胎儿染色体未发生微缺失或微重复。结论array—CGH技术与传统细胞学技术相结合,大大提升产前诊断技术水平。     

采用微阵列-比较基因组杂交进行产前诊断的局限性和困难

应用微阵列-比较基因组杂交(microarray comparative genomic hybridization,aCGH)技术检测基因拷贝数变异(copy Bumber variation,CNV)可对染色体亚微结构异常进行定位,在研究领域和临床实验室中迅速成为一个了解基因和患者遗传病因的有力的工具.由于它在产前诊断上的应用时间较短,目前对aCGH是否可以作为产前诊断工具及其潜在的不确定性存在比较大的争议.此外,对于大多数CNV的表型效应还知之甚少,因此,临床医生向患者进行解释的难度很大,导致许多临床医生拒绝以临床诊断为目的使用aCGH.根据已知的与临床疾病密切相关的一些区域定制的寡核苷酸芯片应运而生,可以降低这种不确定性,在过量信息和信息量不足之间寻求到了一个平衡.本综述的目的是从临床医生的角度探讨aCGH技术用于产前诊断所面临的问题和应用前景.

Abstract：

Subchromosomal abnormalities can be positioned by the detection of copy number variation (CNV) using microarray comparative genomic hybridization (aCGH). aCGH has become a powerful tool in understanding the association between gene and genetic etiology in both research and clinical laboratories.Meanwhile as a new technique, controversies inevitably arose in its clinical application. As for the phenotype of CNV, little has been disclosed. For the clinicians, the difficulty in explanation of the CNV to the patients is obvious, which makes many doctors refuse to use aCGH for clinical diagnosis. Customized arrays have been exploited to decrease the uncertainty and efforts to search for a balance between overloaded information and insufficient information have been made. The purpose of this review is to discuss the current limitations and difficulties on application of aCGH in prenatal diagnosis and its application prospect from the point of a clinician.     

应用微阵列比较基因组杂交技术精确诊断不平衡染色体畸变

目的 探讨微阵列比较基因组杂交技术(array-based comparative genomic hybridization,array-CGH)在诊断不平衡染色体畸变中的应用价值.方法 选取4例常规G显带染色体核型分析未能确诊的不平衡染色体畸变病例,按照标准的Affymetrix SNP 6.0微阵列的操作手册进行杂交、洗涤及全基因组扫描,并通过相应的计算机软件分析结果.结果 通过array-CGH技术分析,明确了所有4例染色体不平衡畸变的诊断并且进行精确定位,其中对2例患者镜下染色体出现无法确定来源的额外条带进行了自身直接重复的确诊;对2例患者G显带无法识别的缺失合并重复的衍生染色体进行了精确诊断.结论 array-CGH技术在DNA水平上对染色体不平衡畸变的诊断具有独特的高分辨率、高敏感性和高特异性,并且能够精确定位,对染色体疾病作出基因型-表型关系的诊断具有重大的应用价值.     

微阵列比较基因组杂交技术诊断9p部分三体患儿一例

目的 确定1例生长发育迟缓、语言发育障碍患儿的核型,分析其染色体畸变与表型的相关性,探讨微阵列比较基因组杂交(array-based comparative genomic hybridization,array-CGH)在临床分子遗传学诊断中的应用及其优越性.方法 应用G显带对患儿及其父母进行核型分析,进一步采用array-CGH技术对患儿进行全基因组高分辨率扫描分析,确定其衍生染色体片段的来源.结果 G显带染色体分析显示患儿及其母亲均为inv(9)(p13q13)携带者,患儿13号染色体存在一衍生片段.array-CGH结果证实患儿衍生片段源自9号染色体短臂,确定为9p13.1-p24.3三体.患儿母亲array-CGH结果未见异常.结论 inv(9)(p13q13)与患儿异常表型无关,患儿的异常表型可归因于9p13.1-p24.3三体.同传统细胞遗传分析方法相比,array-CGH具有高分辨率和高精确性的优点.     

Detection of pathogenic gene copy number variations in patients with mental retardation by genomewide oligonucleotide array comparative genomic hybridization

Genomic imbalance is a major cause of developmental disorders. Microarray-based comparative genomic hybridization (aCGH) has revealed frequent imbalances associated with clinical syndromes, but also a large number of copy number variations (CNVs), which have complicated the interpretation of results. We studied 100 consecutive patients with unexplained mental retardation and a normal karyotype using several platforms of CGH arrays. A genomewide array with 44,290 oligonucleotide probes (OaCGH44K) detected imbalances in 15% of cases studied with sizes ranged from 459 kb to 19 Mb while revealing a small number of CNVs (0.72/individual). Another platform with approximately 240,000 oligonucleotide probes (OaCGH244K) revealed a large number of CNVs (20/individual) in selected cases and their normal parents. We used a comprehensive approach for interpreting the results of aCGH, including consideration of the size, inheritance and gene content of CNVs, and consultation with an online Database of Genomic Variants (DGV) and Online Mendelian Inheritance in Men (OMIM) for information on the genes involved. Our study suggests that genomewide oligonucleotide arrays such as the OaCGH44K platform can be used as a powerful diagnostic tool for detection of genomic imbalances associated with unexplained mental retardation or syndromic autism spectrum disorders. It is interesting to note that a small number of common variants were revealed by OaCGH244K in some study subjects but not in their parents and that some inherited CNVs had altered breakpoints. Further investigations on these alterations may provide useful information for understanding the mechanism of CNVs.     

DNA copy number changes in carcinoma in pleomorphic adenoma of the salivary gland: a comparative genomic hybridization study

Pleomorphic adenoma is the most common benign tumor of the salivary glands and is rarely associated with concurrent epithelial malignancy, which is designated as carcinoma in pleomorphic adenoma (CPA). Genetic abnormalities potentially related to the development of CPA have not been fully investigated. We analyzed DNA copy number changes in each of the adenomatous and carcinomatous components of seven CPA by comparative genomic hybridization using DNA extracted from microdissected tissues of formalin-fixed, paraffin-embedded tumor samples. Carcinomatous components of CPA showed multiple DNA copy number changes at 1-18 different genomic sites (mean 13 sites). Adenomatous components displayed less frequent DNA copy number changes (0-13 sites; mean, 5). In both components, the majority of the changes were gains. The most common recurrent gains in carcinomatous components were seen at 6q (four cases in each), whereas gains at 13q1-2 and 15q1 were most frequently detected in adenomatous components (three cases in each). In five CPA, the same chromosomal regions were involved in the DNA copy number changes detected in both components. Our data suggest that an accumulated or increased number of chromosomal changes including 6q abnormalities may be associated with the development of carcinomatous components in a subset of CPA.