PDF(Pubmed)
Abstract：
Background and aims: Certain chromosomal structural variations (SVs) in biological parents can lead to recurrent spontaneous abortions (RSAs). Unequal crossing over during meiosis can result in the unbalanced rearrangement of gamete chromosomes such as duplication or deletion. Unfortunately, routine techniques such as karyotyping, fluorescence in situ hybridization (FISH), chromosomal microarray analysis (CMA), and copy number variation sequencing (CNV-seq) cannot detect all types of SVs. In this study, we show that optical genome mapping (OGM) quickly and accurately detects SVs for RSA patients with a high resolution and provides more information about the breakpoint regions at gene level. Methods: Seven couples who had suffered RSA with unbalanced chromosomal rearrangements of aborted embryos were recruited, and ultra-high molecular weight (UHMW) DNA was isolated from their peripheral blood. The consensus genome map was created by de novo assembly on the Bionano Solve data analysis software. SVs and breakpoints were identified via alignments of the reference genome GRCh38/hg38. The exact breakpoint sequences were verified using either Oxford Nanopore sequencing or Sanger sequencing. Results: Various SVs in the recruited couples were successfully detected by OGM. Also, additional complex chromosomal rearrangement (CCRs) and four cryptic balanced reciprocal translocations (BRTs) were revealed, further refining the underlying genetic causes of RSA. Two of the disrupted genes identified in this study, FOXK2 [46,XY,t(7; 17)(q31.3; q25)] and PLXDC2 [46,XX,t(10; 16)(p12.31; q23.1)], had been previously shown to be associated with male fertility and embryo transit. Conclusion: OGM accurately detects chromosomal SVs, especially cryptic BRTs and CCRs. It is a useful complement to routine human genetic diagnostics, such as karyotyping, and detects cryptic BRTs and CCRs more accurately than routine genetic diagnostics.
摘要：
背景和目的：亲生父母的某些染色体结构变异（SV）可导致复发性自然流产（RSAs）。减数分裂过程中的不等交叉会导致配子染色体的不平衡重排，例如复制或缺失。不幸的是,常规技术，如核型分析，荧光原位杂交（FISH），染色体微阵列分析（CMA），拷贝数变异测序(CNV-seq)不能检测所有类型的SV。在这项研究中,我们证明光学基因组作图(OGM)能够以高分辨率快速准确地检测RSA患者的SVs,并在基因水平上提供有关断点区域的更多信息.方法：招募7对因流产胚胎染色体重排不平衡而遭受RSA的夫妇，并从其外周血中分离出超高分子量(UHMW)DNA。在BionanoSolve数据分析软件上通过从头组装创建共识基因组图谱。通过参考基因组GRCh38/hg38的比对鉴定SV和断点。使用牛津纳米孔测序或Sanger测序验证确切的断点序列。结果：OGM成功检测到招募夫妇中的各种SV。此外，发现了其他复杂的染色体重排（CCR）和四个隐蔽的平衡相互易位（BRT），进一步完善RSA的潜在遗传原因。在这项研究中发现了两个被破坏的基因，FOXK2[46,XY,t(7;17)(q31.3;q25)]和PLXDC2[46,XX,t(10;16)(p12.31;q23.1)]，先前已证明与男性生育力和胚胎运输有关。结论:OGM能准确检测染色体SVs,尤其是隐秘的BRT和CCR。它是人类常规基因诊断的有用补充，例如核型分析，并且比常规遗传诊断更准确地检测隐匿性BRT和CCR。
