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Rao H, Zhang H, Zou Y, Ma P, Huang T, Yuan H, Zhou J, Lu W, Li Q, Huang S, Liu Y, Yang B. Analysis of chromosomal structural variations in patients with recurrent spontaneous abortion using optical genome mapping. Front Genet 2023; 14:1248755. [PMID: 37732322 PMCID: PMC10507169 DOI: 10.3389/fgene.2023.1248755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 08/21/2023] [Indexed: 09/22/2023] Open
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.
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Affiliation(s)
- Huihua Rao
- Department of Medical Genetics, Jiangxi Maternal and Child Health Hospital, Nanchang, Jiangxi, China
- Jiangxi Key Laboratory of Birth Defect Prevention and Control, Jiangxi Maternal and Child Health Hospital, Nanchang, Jiangxi, China
| | - Haoyi Zhang
- School of Public Health, Nanchang University, Nanchang, Jiangxi, China
| | - Yongyi Zou
- Department of Medical Genetics, Jiangxi Maternal and Child Health Hospital, Nanchang, Jiangxi, China
- Jiangxi Key Laboratory of Birth Defect Prevention and Control, Jiangxi Maternal and Child Health Hospital, Nanchang, Jiangxi, China
| | - Pengpeng Ma
- Department of Medical Genetics, Jiangxi Maternal and Child Health Hospital, Nanchang, Jiangxi, China
- Jiangxi Key Laboratory of Birth Defect Prevention and Control, Jiangxi Maternal and Child Health Hospital, Nanchang, Jiangxi, China
| | - Tingting Huang
- Department of Medical Genetics, Jiangxi Maternal and Child Health Hospital, Nanchang, Jiangxi, China
- Jiangxi Key Laboratory of Birth Defect Prevention and Control, Jiangxi Maternal and Child Health Hospital, Nanchang, Jiangxi, China
| | - Huizhen Yuan
- Department of Medical Genetics, Jiangxi Maternal and Child Health Hospital, Nanchang, Jiangxi, China
- Jiangxi Key Laboratory of Birth Defect Prevention and Control, Jiangxi Maternal and Child Health Hospital, Nanchang, Jiangxi, China
| | - Jihui Zhou
- Department of Medical Genetics, Jiangxi Maternal and Child Health Hospital, Nanchang, Jiangxi, China
- Jiangxi Key Laboratory of Birth Defect Prevention and Control, Jiangxi Maternal and Child Health Hospital, Nanchang, Jiangxi, China
| | - Wan Lu
- Department of Medical Genetics, Jiangxi Maternal and Child Health Hospital, Nanchang, Jiangxi, China
- Jiangxi Key Laboratory of Birth Defect Prevention and Control, Jiangxi Maternal and Child Health Hospital, Nanchang, Jiangxi, China
| | - Qiao Li
- Department of Medical Genetics, Jiangxi Maternal and Child Health Hospital, Nanchang, Jiangxi, China
- Jiangxi Key Laboratory of Birth Defect Prevention and Control, Jiangxi Maternal and Child Health Hospital, Nanchang, Jiangxi, China
| | - Shuhui Huang
- Department of Medical Genetics, Jiangxi Maternal and Child Health Hospital, Nanchang, Jiangxi, China
- Jiangxi Key Laboratory of Birth Defect Prevention and Control, Jiangxi Maternal and Child Health Hospital, Nanchang, Jiangxi, China
| | - Yanqiu Liu
- Department of Medical Genetics, Jiangxi Maternal and Child Health Hospital, Nanchang, Jiangxi, China
- Jiangxi Key Laboratory of Birth Defect Prevention and Control, Jiangxi Maternal and Child Health Hospital, Nanchang, Jiangxi, China
| | - Bicheng Yang
- Department of Medical Genetics, Jiangxi Maternal and Child Health Hospital, Nanchang, Jiangxi, China
- Jiangxi Key Laboratory of Birth Defect Prevention and Control, Jiangxi Maternal and Child Health Hospital, Nanchang, Jiangxi, China
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Mastromoro G, Guadagnolo D, Khaleghi Hashemian N, Marchionni E, Traversa A, Pizzuti A. Molecular Approaches in Fetal Malformations, Dynamic Anomalies and Soft Markers: Diagnostic Rates and Challenges-Systematic Review of the Literature and Meta-Analysis. Diagnostics (Basel) 2022; 12:575. [PMID: 35328129 PMCID: PMC8947110 DOI: 10.3390/diagnostics12030575] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 02/11/2022] [Accepted: 02/21/2022] [Indexed: 02/06/2023] Open
Abstract
Fetal malformations occur in 2-3% of pregnancies. They require invasive procedures for cytogenetics and molecular testing. "Structural anomalies" include non-transient anatomic alterations. "Soft markers" are often transient minor ultrasound findings. Anomalies not fitting these definitions are categorized as "dynamic". This meta-analysis aims to evaluate the diagnostic yield and the rates of variants of uncertain significance (VUSs) in fetuses undergoing molecular testing (chromosomal microarray (CMA), exome sequencing (ES), genome sequencing (WGS)) due to ultrasound findings. The CMA diagnostic yield was 2.15% in single soft markers (vs. 0.79% baseline risk), 3.44% in multiple soft markers, 3.66% in single structural anomalies and 8.57% in multiple structural anomalies. Rates for specific subcategories vary significantly. ES showed a diagnostic rate of 19.47%, reaching 27.47% in multiple structural anomalies. WGS data did not allow meta-analysis. In fetal structural anomalies, CMA is a first-tier test, but should be integrated with karyotype and parental segregations. In this class of fetuses, ES presents a very high incremental yield, with a significant VUSs burden, so we encourage its use in selected cases. Soft markers present heterogeneous CMA results from each other, some of them with risks comparable to structural anomalies, and would benefit from molecular analysis. The diagnostic rate of multiple soft markers poses a solid indication to CMA.
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Affiliation(s)
- Gioia Mastromoro
- Department of Experimental Medicine, Policlinico Umberto I Hospital, Sapienza University of Rome, 00161 Rome, Italy; (D.G.); (N.K.H.); (E.M.); (A.T.); (A.P.)
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