Copy number variation sequencing for diagnosis of cytomegalovirus infection based low-depth whole-genome sequencing technology in fetus:Three cases and literature review

Objective:To summarize the application value of copy number variant sequencing(CNV-seq)in the detection of fetal chromosome and cytomegalovirus load.Methods:The study analyzed the clinical basic data,relevant laboratory tests,treatment process,and outcomes of three patients with positive cytomegalovirus load detected by CNV-seq for fetal chromosomes and cytomegalovirus load,and literature review was done simutaneoubly.Results:In all three cases,the amniotic fluid cytomegalovirus load was less than 105 Copies/ml,and there were no significant neurological abnormalities observed during pregnancy or postpartum follow-up.There is no literature review on the application of CNV-seq technology in the detection of cytomegalovirus infection,only literature reports on genome analysis of CMV-DNA in confirmed patients were available.Conclusion:CNV-seq can be used to detect cytomegalovirus load,which may have a certain degree of predictive value for fetal outcome.CNV-seq can simultaneously detect fetal chromosomes and pathogenic microorganisms,which is of great significance for the prevention and control of birth defects.

Low-depth whole genome sequencing reveals copy number variations associated with higher pathologic grading and more aggressive subtypes of lung non-mucinous adenocarcinoma

Objective:Histology grade,subtypes and TNM stage of lung adenocarcinomas are useful predictors of prognosis and survival.The aim of the study was to investigate the relationship between chromosomal instability,morphological subtypes and the grading system used in lung non-mucinous adenocarcinoma(LNMA).Methods:We developed a whole genome copy number variation(WGCNV)scoring system and applied next generation sequencing to evaluate CNVs present in 91 LNMA tumor samples.Results:Higher histological grades,aggressive subtypes and more advanced TNM staging were associated with an increased WGCNV score,particularly in CNV regions enriched for tumor suppressor genes and oncogenes.In addition,we demonstrate that 24-chromosome CNV profiling can be performed reliably from specific cell types(<100 cells)isolated by sample laser capture microdissection.Conclusions:Our findings suggest that the WGCNV scoring system we developed may have potential value as an adjunct test for predicting the prognosis of patients diagnosed with LNMA.

The role of genomic structural variation in the genetic improvement of polyploid crops

Many of our major crop species are polyploids, containing more than one genome or set of chromosomes. Polyploid crops present unique challenges, including difficulties in genome assembly, in discriminating between multiple gene and sequence copies, and in genetic mapping, hindering use of genomic data for genetics and breeding. Polyploid genomes may also be more prone to containing structural variation, such as loss of gene copies or sequences(presence–absence variation) and the presence of genes or sequences in multiple copies(copynumber variation). Although the two main types of genomic structural variation commonly identified are presence–absence variation and copy-number variation, we propose that homeologous exchanges constitute a third major form of genomic structural variation in polyploids. Homeologous exchanges involve the replacement of one genomic segment by a similar copy from another genome or ancestrally duplicated region, and are known to be extremely common in polyploids. Detecting all kinds of genomic structural variation is challenging, but recent advances such as optical mapping and long-read sequencing offer potential strategies to help identify structural variants even in complex polyploid genomes. All three major types of genomic structural variation(presence–absence, copy-number, and homeologous exchange) are now known to influence phenotypes in crop plants, with examples of flowering time, frost tolerance, and adaptive and agronomic traits. In this review,we summarize the challenges of genome analysis in polyploid crops, describe the various types of genomic structural variation and the genomics technologies and data that can be used to detect them, and collate information produced to date related to the impact of genomic structural variation on crop phenotypes. We highlight the importance of genomic structural variation for the future genetic improvement of polyploid crops.

Association between chromosomal aberration of COX8C and tethered spinal cord syndrome:array-based comparative genomic hybridization analysis

Copy number variations have been found in patients with neural tube abnormalities.In this study,we performed genome-wide screening using high-resolution array-based comparative genomic hybridization in three children with tethered spinal cord syndrome and two healthy parents.Of eight copy number variations,four were non-polymorphic.These non-polymorphic copy number variations were associated with Angelman and Prader-Willi syndromes,and microcephaly.Gene function enrichment analysis revealed that COX8 C,a gene associated with metabolic disorders of the nervous system,was located in the copy number variation region of Patient 1.Our results indicate that array-based comparative genomic hybridization can be used to diagnose tethered spinal cord syndrome.Our results may help determine the pathogenesis of tethered spinal cord syndrome and prevent occurrence of this disease.

Genomic microarrays in prenatal diagnosis

The application of microarray-based techniques for the diagnosis of genomic rearrangements has been steadily growing in popularity since its introduction in 2004.Given the many advantages of these techniques over conventional cytogenetics,there is increasing pressure towards their application in prenatal diagnosis.However,there remain several important issues that must be addressed.For example,microarray-based techniques(comparative genomic hybridization-based arrays and single nucleotide polymorphism-based arrays) allow detection of even very small genomic imbalances that can determine pathological clinical conditions.In addition,there are other copy number variations which represent normal variation,with no detectable effects on phenotype.Given the still incomplete knowledge of the changes in our genome and the associated phenotypes,microarray-based diagnosis is likely to find variants of uncertain and unknown clinical significance.The interpretation of these variants is now a major challenge for the medical geneticist,who often find it difficult to establish precise correlations between genotype and phenotype.There is sufficient available evidence to justify the use of microarray-based diagnostics for a select number of specific conditions,but there is also an inevitable trend towards ever wider application.It is very important that this drift does not progress in an unchecked and uncontrolled manner under the thrust of commercial interests.Therefore,we recommend that scientific societies be vigilant and take an advisory role in the adopting of these technologies as new scientific knowledge becomes available.

Genomic landscape of pancreatic neuroendocrine tumors

AIM:To investigate the prognostic role of genomic stability and copy number alterations(CNAs)pancreatic neuroendocrine tumors(Pan NETs).METHODS:A high-resolution array-based comparative genomic hybridization approach was utilized in order to investigate and quantify chromosomal aberrations in a panel of 37 primary Pan NET and 11 metastatic samples.DNA samples were extracted from formalinfixed and paraffin-embedded tumor specimen.Genomic findings were correlated with histopathological and immunohistochemical data.Moreover,the dataset was subjected to employing an unsupervised hierarchical clustering analysis approach utilizing Euclidean distance and average linkage and associations between genomically defined tumor groups and recurrent CNAs or clinicopathological features of the study group were assessed.RESULTS:Numerous chromosomal aberrations were recurrently detected in both,primary tumor samples and metastases.Copy number gains were most frequently observed at 06p22.2-p22.1(27.1%),17p13.1(20.8%),07p21.3-p21.2(18.8%),09q34.11(18.8%).Genomic losses were significantly less frequent and the only recurrent aberration affected 08q24.3(6.3%).Moreover,we detected a high degree of genomic heterogeneity between primary tumors and metastatic lesions.Unsupervised hierarchical clustering of loci affected by CNAs in more than 3 primary tumor samples revealed two genetically distinct tumor groups as well as two chromosomal clusters of genomic imbalances indicating a small subset of tumors with common molecular features(13.5%).Aberrations affecting6p22.2-22.1,8q24.3,9q34.11 and 17p13.1(P=0.011;0.003;0.003;0.001),were significantly associated with a poorer survival prognosis.CONCLUSION:This study suggests that several frequent CNAs in numerous candidate regions are involved in the pathogenesis and metastatic progression of PanNET.

Fertility,genome stability,and homozygosity in a diverse set of resynthesized rapeseed lines

Rapeseed(Brassica napus,AACC)was formed by hybridization between progenitor species Brassica rapa(AA)and Brassica oleracea(CC).As a result of a limited number of hybridization events between specific progenitor genotypes and strong breeding selection for oil quality traits,rapeseed has limited genetic diversity.The production of resynthesized B.napus lines via interspecific hybridization of the diploid progenitor species B.rapa and B.oleracea is one possible way to increase genetic variation in rapeseed.However,most resynthesized lines produced so far have been reported to be meiotically unstable and infertile,in contrast to established B.napus cultivars.This hinders both maintenance and use of this germplasm in breeding programs.We characterized a large set of 140 resynthesized lines produced by crosses between B.rapa and B.oleracea,as well as between B.rapa and wild C genome species(B.incana,B.hilarionis,B.montana,B.Bourgeaui,B.villosa and B.cretica)for purity(homozygosity),fertility,and genome stability.Self-pollinated seed set,seeds per ten pods as well as percentage pollen viability were used to estimate fertility.SNP genotyping was performed using the Illumina Infinium Brassica 60K array for 116 genotypes,with at least three individuals per line.Most of the material which had been advanced through multiple generations was no longer pure,with heterozygosity detected corresponding to unknown parental contributions via outcrossing.Fertility and genome stability were both genotypedependent.Most lines had high numbers of copy number variants(CNVs),indicative of meiotic instability,and high numbers of CNVs were significantly associated with reduced fertility.Eight putatively stable resynthesized B.napus lines were observed.Further investigation of these lines may reveal the mechanisms underlying this effect.Our results suggest that selection of stable resynthesized lines for breeding purposes is possible.

低深度全基因组测序技术在复发性流产遗传学病因诊断中的应用

目的应用低深度全基因组拷贝数变异分析(CNV-seq)技术研究胚胎染色体异常在复发性流产(RSA)及偶发流产(SA)中的差异。方法采集158例RSA患者(RSA组)和244例SA患者(SA组)的流产组织进行CNV-seq检测,对可疑染色体异常的夫妇进行高分辨外周血染色体核型检测。结果402例样本中有2例检测失败,检测成功率99.5%(400/402)。共检测出染色体异常238例(59.5%),包括染色体数目异常212例(89.1%),致病性拷贝数变异25例(10.5%),单亲二倍体1例(0.4%)。RSA组和SA组总体染色体异常、非整倍体、三倍体发生率差异均无统计学意义。RSA组致病性拷贝数变异在染色体异常中的构成比显著高于SA组(P<0.05)。高分辨外周血核型分析检测共发现4例平衡易位携带者。35~39岁年龄段中SA组胚胎染色体异常率高于RSA组(P<0.05)。2组早期流产中胚胎染色体异常率均明显高于中期流产;早期流产中,SA组的流产组织(POC)染色体异常率高于RSA组(P<0.05)。结论CNV-seq可以对胚胎染色体数目异常和染色体片段重复/缺失进行精准诊断,在RSA和SA的遗传学病因诊断中同样重要,可为再生育指导提供依据。

牦牛基因组拷贝数变异研究进展

拷贝数变异(copy number variation, CNV)是基因组结构变异(structural variation, SV)的重要组成部分。与SNP(single nucleotide polymorphism)相比,CNV显示出更丰富的复杂遗传变异,在家畜重要经济性状遗传机理、疾病诱因和物种进化等研究方面具有重要意义。牦牛作为青藏高原的重要牛种,近年来随着高通量测序技术的快速发展和参考基因组的不断升级,其全基因组水平上CNV的研究获得重要进展。本文在阐述基因组CNV的形成原理、作用机制和检测方法基础上,综述了近10年来牦牛基因组CNV的研究现状,分析探究了存在的一些问题与不足,并对其未来的发展和应用趋势进行了展望,以期为深入开展牦牛基因组研究和加速牦牛遗传资源的分子育种进程提供参考。

高通量测序数据的基因组拷贝数变异[]检测方法综述

拷贝数变异是指基因组中发生大片段的DNA序列的拷贝数增加或者减少。根据现有的研究可知,拷贝数变异是多种人类疾病的成因,与其发生与发展机制密切相关。高通量测序技术的出现为拷贝数变异检测提供了技术支持,在人类疾病研究、临床诊疗等领域,高通量测序技术已经成为主流的拷贝数变异检测技术。虽然不断有新的基于高通量测序技术的算法和软件被人们开发出来,但是准确率仍然不理想。本文全面地综述基于高通量测序数据的拷贝数变异检测方法,包括基于reads深度的方法、基于双末端映射的方法、基于拆分read的方法、基于从头拼接的方法以及基于上述4种方法的组合方法,深入探讨了每类不同方法的原理,代表性的软件工具以及每类方法适用的数据以及优缺点等,并展望未来的发展方向。

CNV-seq在流产物遗传学检测中的应用及相关基因的富集分析

目的 探讨基于二代测序的染色体拷贝数变异技术(CNV-seq)在流产物染色体异常检测中的应用效果和临床意义未明的CNVs变异在流产物病因中的作用。方法 选取2020年1月至2022年12月在沈阳市妇幼保健院因胚胎停育或自然流产,自愿行流产物分析的患者178例,对绒毛或皮肤组织进行DNA提取和CNV-seq检测。对临床意义未明的CNVs变异涉及的基因进行富集分析。结果 178例流产物样本中,致病性CNVs 93例(93/178,52.25%),其中染色体数目异常占46.63%,结构异常占5.62%。不同年龄段患者的致病性CNV与非致病性CNV差异有统计学意义(P=0.046)。染色体数目异常中45,X (16.87%)、69,XNN (12.05%)和47,XN,+16 (12.05%)的发病率位列前三位,双重三体7例,三重三体1例,结构异常中共检出综合征10例。KEGG显著富集的是Pantothenate and CoA biosynthesis (P=0.001),GO显著富集的是MHC class I protein binding I (GO:0042288,P=9.04E-05)。结论 半数以上流产是由染色体异常引起的,CNV-seq利于发现罕见的综合征。对临床意义未明的CNVs涉及的基因进行富集可为寻找流产物标记基因提供新的思路。

染色体核型分析联合CNV-Seq检测在高龄孕妇产前诊断中的应用

目的探讨染色体核型分析与全基因组拷贝数变异测序(CNV-Seq)技术在高龄孕妇产前诊断中联合应用的意义。方法对2020年1月至2022年12月该院收治的723例高龄孕妇的羊水细胞染色体核型分析、CNV-Seq检测结果进行回顾性分析。结果723例高龄孕妇中检出染色体异常共29例,异常检出率为4.0%。723例高龄孕妇中检出核型异常21例,异常检出率为2.9%,其中染色体非整倍体13例,包括21-三体7例,18-三体1例,性染色体非整倍体5例;染色体嵌合3例,包括性染色体嵌合2例,常染色体嵌合1例;染色体结构异常5例,包括染色体倒位3例,染色体易位2例;检出CNV-Seq异常24例,异常检出率为3.3%,其中染色体非整倍体13例,包括21-三体7例,18-三体1例,性染色体非整倍体5例;染色体嵌合3例,包括性染色体嵌合2例,常染色体嵌合1例;致病性染色体拷贝数变异8例,包括染色体微重复1例,染色体微缺失7例。其中染色体非整倍体异常中染色体核型分析和CNV-Seq检测结果一致。结论染色体核型分析联合CNV-Seq检测可提高染色体异常检出率,两种方法各自有独特的优势,可以相互验证,互补不足,染色体核型分析可比较直观地检测出染色体结构变异,而CNV-Seq可检测出染色体微缺失、微重复。

Copy number variation profile-based genomic typing of premenstrual dysphoric disorder in Chinese

Premenstrual dysphoric disorder(PMDD) affects nearly 5% of women of reproductive age. Symptomatic heterogeneity, together with largely unknown genetics, has greatly hindered its effective treatment. In the present study, analysis of genomic sequencing-based copy number variations(CNVs) called from 100 kb white blood cell DNA sequence windows by means of semisupervized clustering led to the segregation of patient genomes into the D and V groups, which correlated with the depression and invasion clinical types,respectively, with 89.0% consistency. Application of diagnostic CNV features selected using the correlation-based machine learning method enabled the classification of the CNVs obtained into the D group, V group, total patient group, and control group with an average accuracy of 83.0%. The power of the diagnostic CNV features was 0.98 on average, suggesting that these CNV features could be used for the molecular diagnosis of the major clinical types of PMDD. This demonstrated concordance between the CNV profiles and clinical types of PMDD supported the validity of symptom-based diagnosis of PMDD for differentiating between its two major clinical types, as well as the predominantly genetic nature of PMDD with a host of overlaps between multiple susceptibility genes/pathways and the diagnostic CNV features as indicators of involvement in PMDD etiology.

Statistical analysis for genome-wide association study

In the past few years, genome-wide association study （GWAS） has made great successes in identifying genetic susceptibility loci underlying many complex diseases and traits. The findings provide important genetic insights into understanding pathogenesis of diseases. In this paper, we present an overview of widely used approaches and strategies for analysis of GWAS, offered a general consideration to deal with GWAS data. The issues regarding data quality control, population structure, association analysis, multiple comparison and visual presentation of GWAS results are discussed; other advanced topics including the issue of missing heritability, meta-analysis, setbased association analysis, copy number variation analysis and GWAS cohort analysis are also briefly introduced.

1例X连锁隐性遗传鱼鳞病合并隐睾患儿家系的遗传学分析

目的:对1例X连锁隐性遗传鱼鳞病合并隐睾的患儿及其家系成员进行遗传学分析,探讨其致病原因。方法:对患儿及其家庭成员进行常规染色体G显带核型分析和低深度全基因组拷贝数变异测序分析(CNV-seq)。结果:染色体核型分析未见明显异常。CNV-seq检测发现患儿及哥哥和母亲的X染色体p22.33-p22.31处缺失5.28Mb区域,该片段包含Xp22.31 recurrent region (includes STS)全部。结论:患儿X染色体拷贝数变异遗传自其母亲,Xp22.31缺失是该患儿异常表型的遗传学病因。

利用人类全基因组亚硫酸氢盐测序数据检测CNVs的研究

DNA甲基化异常可能导致拷贝数变异(copy number variants,CNVs)的发生,而CNVs的发生又可能改变DNA甲基化水平。全基因组亚硫酸氢盐测序(whole genome bisulfite sequencing,WGBS)技术能够获得DNA水平的测序数据,具有挖掘CNVs的潜力和优势,但利用WGBS数据挖掘CNVs的效果尚不清楚。本研究选取了5款检测CNVs不同策略的软件(BreakDancer、cn.mops、CNVnator、DELLY、Pindel),基于人类的真实(2.62 billion reads)和模拟(12.35 billion reads)测序数据,进行150次CNVs检测,评估CNVs检出数量、精确率、召回率、相对检出能力、内存占用和运行时间等指标,旨在讨论利用WGBS数据检测CNVs的最佳方案。基于真实WGBS数据,Pindel检出缺失型和重复型CNVs的数量最多,CNVnator对缺失型CNVs的检测精确率最高,cn.mops对重复型CNVs的检测精确率最高,Pindel对缺失型CNVs的召回率最高,cn.mops对重复型CNVs的召回率最高。基于模拟WGBS数据,BreakDancer检出缺失型CNVs数量最多,cn.mops检出重复型CNVs数量最多,CNVnator对缺失型和重复型CNVs的检测精确率和召回率均为最高。与全基因组测序数据相比,CNVnator在真实和模拟WGBS数据中检出CNVs的能力与之相当。此外,DELLY和BreakDancer的内存占用峰值和CPU运行时间最小,CNVnator的内存占用峰值和CPU运行时间最大。结果表明,利用WGBS数据检测CNVs具有可行性,使用CNVnator和cn.mops在WGBS数据上检测CNVs的准确率较高,这些工作为利用WGBS数据深入研究CNVs和DNA甲基化之间的相互关系提供一定的参考和帮助。

伍隍猪和内江猪拷贝数变异差异与嘴型全基因组关联分析

【目的】探究伍隍猪与内江猪群体之间全基因组拷贝数变异(CNV)差异,并寻找影响伍隍猪嘴型性状的候选基因。【方法】基于50K SNP芯片数据,使用PennCNV和R-Gada检测131头伍隍猪与156头内江猪全基因组拷贝数变异差异,并通过全基因组关联分析(GWAS)筛选伍隍猪嘴型性状候选基因。【结果】伍隍猪的平均嘴长[(11.12±2.78)cm]显著长于内江猪[(5.04±1.26)cm,P<0.05]。伍隍猪相较于内江猪缺失型CNV增加;获得型CNV减少。拷贝数变异区域注释后的差异基因主要富集在破骨细胞分化、能量代谢、神经退行性病变等通路。GWAS分析共得到11个基因与嘴型相关。【结论】通过检测伍隍猪与内江猪群体间拷贝数变异差异,鉴定到GORASP2、CWC22、TMEM64为嘴长表型的候选基因,为后续伍隍猪遗传资源的鉴定提供新证据。

胚胎停育患者绒毛组织染色体检测分析

目的分析胚胎停育患者绒毛组织染色体检测结果。方法选取胚胎停育患者的流产绒毛组织240例份,采用基因组拷贝数变异测序检测染色体。结果240例份胚胎停育患者流产绒毛组织中,染色体异常181例份、染色体正常59例份。181例份染色体异常绒毛组织中,染色体数目异常97例份,其中常染色体三体76例份、性染色体单体18例份、三倍体3例份;结构异常120例份;部分标本同时出现染色体数目异常和结构异常。育龄(208例)和高龄(32例)胚胎停育患者流产绒毛组织中染色体异常分别为157例份、24例份。育龄者常染色体三体61例份、性染色体单体16例份、三倍体3例份,高龄者分别为15、2、0例份,两者常染色体三体例份数比较,P<0.05。胚胎停育1次、2次、3次、4次、≥5次患者(136、51、33、15、5例)流产绒毛组织染色体异常例份数分别为100、46、22、9、4例份,胚胎停育2次者分别与胚胎停育3次、4次者比较,P均<0.05。胚胎停育1次、2次、3次、4次、≥5次患者流产绒毛组织染色体数目异常例份数分别为58、26、11、2、0例份,胚胎停育1次者、2次者分别与胚胎停育4次者比较,P均<0.05。CNV一共检测出120例份,其中18例份为致病性,2例份为可能致病,87例份为临床意义未明,13例份为可能良性。结论胚胎停育患者流产绒毛组织染色体异常率较高,异常类型为染色体数目异常或结构异常,常染色体多数以三体发生常见,其中16-三体发生率最高,其次为22-三体、15-三体、21-三体等;性染色体异常以X单体为常见。育龄和高龄胚胎停育患者流产绒毛组织染色体异常无差异,但不同胚胎停育次数患者流产绒毛组织染色体异常存在差异。

基于低深度全基因组测序技术的拷贝数变异测序辅助诊断胎儿巨细胞病毒感染3例并文献复习

目的:总结拷贝数变异测序(copy number variant sequencing,CNV‐seq)对检测胎儿染色体及巨细胞病毒载量的应用价值。方法:分析CNV‐seq检测胎儿染色体及巨细胞病毒载量的3例巨细胞病毒载量阳性患者的临床基础资料、相关实验室检查、治疗过程及转归并文献复习。结果:3例病例中患者羊水巨细胞病毒载量均小于105 Copies/mL,且其孕期临床表现、产后随访均未见明显神经系统异常。文献复习未见有关CNV‐seq技术应用于巨细胞病毒感染的检测,仅有对已确诊患者进行CMV‐DNA的基因组分析的文献报道。结论:CNV‐seq可用于巨细胞病毒载量的检测,其病毒载量对胎儿的结局可能具有一定程度的预判价值。CNV‐seq可同时检测胎儿染色体及病原微生物,对于出生缺陷防控有着重要意义。

利用全基因组重测序数据检测8个鸭品种基因组拷贝数变异

旨在鉴别与鸭重要经济性状潜在相关的拷贝数变异(copy number variations,CNVs),为解析CNVs对鸭经济性状的影响提供前期研究基础。本研究利用从美国国家生物技术信息中心(National Center for Biotechnology Information,NCBI)公共数据库中下载的8个鸭品种共78个个体的全基因组重测序数据,采用CNVnator和CNVcaller软件进行全基因组CNVs检测,同时只保留两个软件检测结果中存在至少1 bp重叠的同类型CNVRs,以消除假阳性对试验结果的影响。结果显示,8个鸭品种的CNVs合并后共检测出7550个CNV regions(CNVRs),其中包括7098个duplications和452个deletions。这些CNVRs在鸭29条常染色体上呈不均匀分布,总长度为16111.2 kb,平均长度为2134 bp,约占鸭基因组的1.51%。此外,本研究在8个鸭品种共筛选到4304个潜在的品种特异性CNVRs,覆盖1230个注释基因。通过基因功能Gene Ontology(GO)富集分析,鉴别到38个可能与生长和繁殖相关的CNVRs。本研究共发现7550个CNVRs,筛选出4304个潜在的品种特异性CNVRs,并鉴别到38个与鸭生长和繁殖潜在相关的CNVRs,为深入探究CNVs对鸭重要经济性状的影响提供了必要的研究基础。