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We reanalyzed through a cytogenomics approach a case published 20 years ago, describing a girl with developmental delay and epilepsy. Karyotype and FISH analysis showed a de novo 2.3 Mb terminal inverted-duplication at 8q24.3. The interpretation was inconsistent with the absence of a more distal deletion as expected for distal inverted duplications, and it was inconceivable to highlight rearrangements smaller than 5-10 Mb at that time. Chromosomal microarray (CMA), optical genome mapping (OGM), and short-read whole genome sequencing (srWGS) identified a complex configuration at 8q24.3, which resembles events like chromoanasynthesis or DUP-TRP/INV-DUP (duplication-triplication/inverted-duplication), both characterized by clustered duplications and triplications, some of which are inverted. In the EBV-line genes located in the amplified regions were overexpressed. Despite a more precise definition of the imbalance, we were unable to provide a clear-cut explanation for the proband's clinical features.
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http://dx.doi.org/10.1038/s41431-025-01883-0 | DOI Listing |
Methods Mol Biol
August 2025
Laboratoire de Diagnostic Génétique, Hôpitaux Universitaires de Strasbourg, Strasbourg, France.
Chromoanagenesis correspond to cataclysmic complex chromosomal rearrangements. They are separated into three categories-chromothripsis, chromoanasynthesis, and chromoplexy-based, among others, on the number of breakpoints, the copy number state, and the molecular signature at junctions. However, criteria may be overlapping or may be difficult to evaluate, leading to blurred border between the three types of chromoanagenesis and even other complex chromosomal rearrangements.
View Article and Find Full Text PDFGenes (Basel)
July 2025
Institute of Genomic Medicine and Department of Pathology, Nationwide Children's Hospital, The Ohio State University, Columbus, OH 43215, USA.
Optical genome mapping (OGM) has recently emerged as a new technology in the clinical cytogenomics laboratories. This methodology has the ability to detect balanced and unbalanced structural rearrangements using ultra-high molecular weight DNA. This article discusses the uses of this new technology in both constitutional and somatic settings, its advantages as well as opportunity for improvements.
View Article and Find Full Text PDFJ Mol Diagn
August 2025
Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington. Electronic address:
Structural variants are critical to genetic diversity and disease, yet their detection remains challenging with conventional cytogenetic techniques, including karyotyping, fluorescence in situ hybridization, and chromosome microarray analysis. These methods often lack the resolution and sensitivity needed for comprehensive characterization of chromosomal aberrations. To address these limitations, we implemented genomic proximity mapping (GPM), a genome-wide chromosome conformation capture technology, in a clinical setting.
View Article and Find Full Text PDFNPJ Genom Med
July 2025
Department of Genetics, Institut Curie, Paris, France.
Pathogenicity assessment of genetic variants is the cornerstone of genetic counselling. Copy gains of exons are challenging, as pathogenicity depends on the localization of the additional exons. Eight patients form six families carried copy gains of BRCA1 exons 8-20.
View Article and Find Full Text PDFClin Genet
July 2025
Université de Poitiers, INSERM 1084, LNEC, Poitiers, France.
Over the past 15 years, molecular methods for human genome analysis have evolved significantly, becoming integral to routine genetic diagnostics. Among various genomic alterations, copy-number variations (CNVs) are particularly important as sources of both benign and pathogenic variants. Accurate assessment of these variants' clinical implications is critical, especially for rare, non-recurrent CNVs and for susceptibility loci linked to neurodevelopmental disorders (NDDs).
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