1
|
Barseghyan H, Eisenreich D, Lindt E, Wendlandt M, Scharf F, Benet-Pages A, Sendelbach K, Neuhann T, Abicht A, Holinski-Feder E, Koehler U. Optical Genome Mapping as a Potential Routine Clinical Diagnostic Method. Genes (Basel) 2024; 15:342. [PMID: 38540401 PMCID: PMC10970541 DOI: 10.3390/genes15030342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 02/29/2024] [Accepted: 03/01/2024] [Indexed: 06/14/2024] Open
Abstract
Chromosome analysis (CA) and chromosomal microarray analysis (CMA) have been successfully used to diagnose genetic disorders. However, many conditions remain undiagnosed due to limitations in resolution (CA) and detection of only unbalanced events (CMA). Optical genome mapping (OGM) has the potential to address these limitations by capturing both structural variants (SVs) resulting in copy number changes and balanced rearrangements with high resolution. In this study, we investigated OGM's concordance using 87 SVs previously identified by CA, CMA, or Southern blot. Overall, OGM was 98% concordant with only three discordant cases: (1) uncalled translocation with one breakpoint in a centromere; (2) uncalled duplication with breakpoints in the pseudoautosomal region 1; and (3) uncalled mosaic triplication originating from a marker chromosome. OGM provided diagnosis for three previously unsolved cases: (1) disruption of the SON gene due to a balanced reciprocal translocation; (2) disruption of the NBEA gene due to an inverted insertion; (3) disruption of the TSC2 gene due to a mosaic deletion. We show that OGM is a valid method for the detection of many types of SVs in a single assay and is highly concordant with legacy cytogenomic methods; however, it has limited SV detection capabilities in centromeric and pseudoautosomal regions.
Collapse
Affiliation(s)
- Hayk Barseghyan
- Medical Genetics Center (MGZ), 80335 Munich, Germany
- Center for Genetic Medicine Research, Children’s National Research Institute, Children’s National Hospital, Washington, DC 20012, USA
| | | | - Evgenia Lindt
- Medical Genetics Center (MGZ), 80335 Munich, Germany
| | - Martin Wendlandt
- Institute of Medical Biochemistry and Molecular Biology, University Medicine of Greifswald, 17489 Greifswald, Germany
| | | | | | | | | | - Angela Abicht
- Medical Genetics Center (MGZ), 80335 Munich, Germany
- Friedrich-Baur-Institute, Department of Neurology, Klinikum der Universität, Ludwig-Maximilians-Universität, 80336 Munich, Germany
| | - Elke Holinski-Feder
- Medical Genetics Center (MGZ), 80335 Munich, Germany
- Department of Medicine IV, Klinikum der Universität, Ludwig-Maximilians-Universität, 80336 Munich, Germany
| | - Udo Koehler
- Medical Genetics Center (MGZ), 80335 Munich, Germany
| |
Collapse
|
2
|
Barseghyan H, Pang AWC, Clifford B, Serrano MA, Chaubey A, Hastie AR. Comparative Benchmarking of Optical Genome Mapping and Chromosomal Microarray Reveals High Technological Concordance in CNV Identification and Additional Structural Variant Refinement. Genes (Basel) 2023; 14:1868. [PMID: 37895217 PMCID: PMC10667989 DOI: 10.3390/genes14101868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 09/13/2023] [Accepted: 09/18/2023] [Indexed: 10/29/2023] Open
Abstract
The recommended practice for individuals suspected of a genetic etiology for disorders including unexplained developmental delay/intellectual disability (DD/ID), autism spectrum disorders (ASD), and multiple congenital anomalies (MCA) involves a genetic testing workflow including chromosomal microarray (CMA), Fragile-X testing, karyotype analysis, and/or sequencing-based gene panels. Since genomic imbalances are often found to be causative, CMA is recommended as first tier testing for many indications. Optical genome mapping (OGM) is an emerging next generation cytogenomic technique that can detect not only copy number variants (CNVs), triploidy and absence of heterozygosity (AOH) like CMA, but can also define the location of duplications, and detect other structural variants (SVs), including balanced rearrangements and repeat expansions/contractions. This study compares OGM to CMA for clinically reported genomic variants, some of these samples also have structural characterization by fluorescence in situ hybridization (FISH). OGM was performed on IRB approved, de-identified specimens from 55 individuals with genomic abnormalities previously identified by CMA (61 clinically reported abnormalities). SVs identified by OGM were filtered by a control database to remove polymorphic variants and against an established gene list to prioritize clinically relevant findings before comparing with CMA and FISH results. OGM results showed 100% concordance with CMA findings for pathogenic variants and 98% concordant for all pathogenic/likely pathogenic/variants of uncertain significance (VUS), while also providing additional insight into the genomic structure of abnormalities that CMA was unable to provide. OGM demonstrates equivalent performance to CMA for CNV and AOH detection, enhanced by its ability to determine the structure of the genome. This work adds to an increasing body of evidence on the analytical validity and ability to detect clinically relevant abnormalities identified by CMA. Moreover, OGM identifies translocations, structures of duplications and complex CNVs intractable by CMA, yielding additional clinical utility.
Collapse
Affiliation(s)
- Hayk Barseghyan
- Bionano, San Diego, CA 92121, USA; (H.B.); (A.W.C.P.); (B.C.); (A.C.)
- Center for Genetic Medicine Research, Children’s National Hospital, Washington, DC 20010, USA
- Genomics and Precision Medicine, School of Medicine and Health Sciences, George Washington University, Washington, DC 20037, USA
| | | | - Benjamin Clifford
- Bionano, San Diego, CA 92121, USA; (H.B.); (A.W.C.P.); (B.C.); (A.C.)
| | | | - Alka Chaubey
- Bionano, San Diego, CA 92121, USA; (H.B.); (A.W.C.P.); (B.C.); (A.C.)
| | - Alex R. Hastie
- Bionano, San Diego, CA 92121, USA; (H.B.); (A.W.C.P.); (B.C.); (A.C.)
| |
Collapse
|
3
|
Yilmaz F, Gurusamy U, Mosley TJ, Hallast P, Kim K, Mostovoy Y, Purcell RH, Shaikh TH, Zwick ME, Kwok PY, Lee C, Mulle JG. High level of complexity and global diversity of the 3q29 locus revealed by optical mapping and long-read sequencing. Genome Med 2023; 15:35. [PMID: 37165454 PMCID: PMC10170684 DOI: 10.1186/s13073-023-01184-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 04/20/2023] [Indexed: 05/12/2023] Open
Abstract
BACKGROUND High sequence identity between segmental duplications (SDs) can facilitate copy number variants (CNVs) via non-allelic homologous recombination (NAHR). These CNVs are one of the fundamental causes of genomic disorders such as the 3q29 deletion syndrome (del3q29S). There are 21 protein-coding genes lost or gained as a result of such recurrent 1.6-Mbp deletions or duplications, respectively, in the 3q29 locus. While NAHR plays a role in CNV occurrence, the factors that increase the risk of NAHR at this particular locus are not well understood. METHODS We employed an optical genome mapping technique to characterize the 3q29 locus in 161 unaffected individuals, 16 probands with del3q29S and their parents, and 2 probands with the 3q29 duplication syndrome (dup3q29S). Long-read sequencing-based haplotype resolved de novo assemblies from 44 unaffected individuals, and 1 trio was used for orthogonal validation of haplotypes and deletion breakpoints. RESULTS In total, we discovered 34 haplotypes, of which 19 were novel haplotypes. Among these 19 novel haplotypes, 18 were detected in unaffected individuals, while 1 novel haplotype was detected on the parent-of-origin chromosome of a proband with the del3q29S. Phased assemblies from 44 unaffected individuals enabled the orthogonal validation of 20 haplotypes. In 89% (16/18) of the probands, breakpoints were confined to paralogous copies of a 20-kbp segment within the 3q29 SDs. In one del3q29S proband, the breakpoint was confined to a 374-bp region using long-read sequencing. Furthermore, we categorized del3q29S cases into three classes and dup3q29S cases into two classes based on breakpoints. Finally, we found no evidence of inversions in parent-of-origin chromosomes. CONCLUSIONS We have generated the most comprehensive haplotype map for the 3q29 locus using unaffected individuals, probands with del3q29S or dup3q29S, and available parents, and also determined the deletion breakpoint to be within a 374-bp region in one proband with del3q29S. These results should provide a better understanding of the underlying genetic architecture that contributes to the etiology of del3q29S and dup3q29S.
Collapse
Affiliation(s)
- Feyza Yilmaz
- The Jackson Laboratory for Genomic Medicine, 10 Discovery Drive, Farmington, CT, 06032, USA
| | - Umamaheswaran Gurusamy
- Cardiovascular Research Institute and Institute for Human Genetics, UCSF School of Medicine, 513 Parnassus Ave, San Francisco, CA, 94143, USA
| | - Trenell J Mosley
- Graduate Program in Genetics and Molecular Biology, Laney Graduate School, Emory University, 201 Dowman Drive, Atlanta, GA, 30322, USA
| | - Pille Hallast
- The Jackson Laboratory for Genomic Medicine, 10 Discovery Drive, Farmington, CT, 06032, USA
| | - Kwondo Kim
- The Jackson Laboratory for Genomic Medicine, 10 Discovery Drive, Farmington, CT, 06032, USA
| | - Yulia Mostovoy
- Cardiovascular Research Institute and Institute for Human Genetics, UCSF School of Medicine, 513 Parnassus Ave, San Francisco, CA, 94143, USA
| | - Ryan H Purcell
- Laboratory of Translational Cell Biology, Department of Cell Biology, Emory University School of Medicine, 100 Woodruff Circle, Atlanta, GA, 30322, USA
| | - Tamim H Shaikh
- Department of Pediatrics, Section of Genetics and Metabolism, University of Colorado School of Medicine, 13123 E 16Th Ave, Aurora, CO, 80045, USA
| | - Michael E Zwick
- Department of Genetics, Rutgers University-New Brunswick, Rutgers University, Piscataway, New Brunswick, NJ, 08901, USA
| | - Pui-Yan Kwok
- Cardiovascular Research Institute and Institute for Human Genetics, UCSF School of Medicine, 513 Parnassus Ave, San Francisco, CA, 94143, USA
- Department of Dermatology, UCSF School of Medicine, 1701 Divisadero Street, San Francisco, CA, 94115, USA
| | - Charles Lee
- The Jackson Laboratory for Genomic Medicine, 10 Discovery Drive, Farmington, CT, 06032, USA.
| | - Jennifer G Mulle
- Department of Psychiatry, Robert Wood Johnson Medical School, Rutgers Biomedical and Health Sciences, Rutgers University, 671 Hoes Lane, New Brunswick, NJ, 08901, USA.
| |
Collapse
|
4
|
Shi S, Huang P, Yan R, Li R. Identification of complex and cryptic chromosomal rearrangements by optical genome mapping. Mol Cytogenet 2023; 16:5. [PMID: 37101225 PMCID: PMC10134526 DOI: 10.1186/s13039-023-00636-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Accepted: 04/12/2023] [Indexed: 04/28/2023] Open
Abstract
BACKGROUND Optical genome mapping (OGM) has developed into a highly promising method for detecting structural variants (SVs) in human genomes. Complex chromosomal rearrangements (CCRs) and cryptic translocations are rare events that are considered difficult to detect by routine cytogenetic methods. In this study, OGM was applied to delineate the precise chromosomal rearrangements in three cases with uncertain or unconfirmed CCRs detected by conventional karyotyping and one case with a cryptic translocation suggested by fetal chromosomal microarray analysis (CMA). RESULTS In the three cases with CCRs, OGM not only confirmed or revised the original karyotyping results but also refined the precise chromosomal structures. In the case with a suspected translocation not detected by karyotyping, OGM efficiently identified the cryptic translocation and defined the genomic breakpoints with relatively high accuracy. CONCLUSIONS Our study confirmed OGM as a robust alternative approach to karyotyping for the detection of chromosomal structural rearrangements, including CCRs and cryptic translocations.
Collapse
Affiliation(s)
- Shanshan Shi
- Fetal Medicine Center, Department of Obstetrics and Gynecology, The First Affiliated Hospital, Jinan University, No. 613 Huangpu West Road, Guangzhou, 510630, People's Republic of China
| | - Peizhi Huang
- Prenatal Diagnosis Center, Department of Obstetrics and Gynecology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Ruiling Yan
- Fetal Medicine Center, Department of Obstetrics and Gynecology, The First Affiliated Hospital, Jinan University, No. 613 Huangpu West Road, Guangzhou, 510630, People's Republic of China.
| | - Ruiman Li
- Fetal Medicine Center, Department of Obstetrics and Gynecology, The First Affiliated Hospital, Jinan University, No. 613 Huangpu West Road, Guangzhou, 510630, People's Republic of China.
| |
Collapse
|
5
|
Levy B, Baughn LB, Akkari Y, Chartrand S, LaBarge B, Claxton D, Lennon PA, Cujar C, Kolhe R, Kroeger K, Pitel B, Sahajpal N, Sathanoori M, Vlad G, Zhang L, Fang M, Kanagal-Shamanna R, Broach JR. Optical genome mapping in acute myeloid leukemia: a multicenter evaluation. Blood Adv 2023; 7:1297-1307. [PMID: 36417763 PMCID: PMC10119592 DOI: 10.1182/bloodadvances.2022007583] [Citation(s) in RCA: 30] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 11/04/2022] [Accepted: 11/05/2022] [Indexed: 11/25/2022] Open
Abstract
Detection of hallmark genomic aberrations in acute myeloid leukemia (AML) is essential for diagnostic subtyping, prognosis, and patient management. However, cytogenetic/cytogenomic techniques used to identify those aberrations, such as karyotyping, fluorescence in situ hybridization (FISH), or chromosomal microarray analysis (CMA), are limited by the need for skilled personnel as well as significant time, cost, and labor. Optical genome mapping (OGM) provides a single, cost-effective assay with a significantly higher resolution than karyotyping and with a comprehensive genome-wide analysis comparable with CMA and the added unique ability to detect balanced structural variants (SVs). Here, we report in a real-world setting the performance of OGM in a cohort of 100 AML cases that were previously characterized by karyotype alone or karyotype and FISH or CMA. OGM identified all clinically relevant SVs and copy number variants (CNVs) reported by these standard cytogenetic methods when representative clones were present in >5% allelic fraction. Importantly, OGM identified clinically relevant information in 13% of cases that had been missed by the routine methods. Three cases reported with normal karyotypes were shown to have cryptic translocations involving gene fusions. In 4% of cases, OGM findings would have altered recommended clinical management, and in an additional 8% of cases, OGM would have rendered the cases potentially eligible for clinical trials. The results from this multi-institutional study indicate that OGM effectively recovers clinically relevant SVs and CNVs found by standard-of-care methods and reveals additional SVs that are not reported. Furthermore, OGM minimizes the need for labor-intensive multiple cytogenetic tests while concomitantly maximizing diagnostic detection through a standardized workflow.
Collapse
Affiliation(s)
- Brynn Levy
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY
| | - Linda B. Baughn
- Division of Laboratory Genetics and Genomics, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN
| | - Yassmine Akkari
- Steve and Cindy Rasmussen Institute for Genomic Medicine, Nationwide Children’s Hospital, Columbus, OH
| | - Scott Chartrand
- Department of Biochemistry and Molecular Biology, Penn State College of Medicine, Hershey, PA
| | - Brandon LaBarge
- Department of Otolaryngology, Penn State College of Medicine, Hershey, PA
| | - David Claxton
- Department of Hematology and Oncology, Department of Medicine, Penn State College of Medicine, Hershey, PA
| | | | - Claudia Cujar
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY
| | - Ravindra Kolhe
- Department of Pathology, Medical College of Georgia at Augusta University, Augusta, GA
| | - Kate Kroeger
- Cytogenetics Laboratory, Seattle Cancer Care Alliance, Seattle, WA
| | - Beth Pitel
- Division of Laboratory Genetics and Genomics, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN
| | - Nikhil Sahajpal
- Department of Pathology, Medical College of Georgia at Augusta University, Augusta, GA
| | | | - George Vlad
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY
| | - Lijun Zhang
- Department of Biochemistry and Molecular Biology, Penn State College of Medicine, Hershey, PA
| | - Min Fang
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA
| | - Rashmi Kanagal-Shamanna
- Department of Hematopathology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - James R. Broach
- Department of Biochemistry and Molecular Biology, Penn State College of Medicine, Hershey, PA
| |
Collapse
|
6
|
Vervoort L, Vermeesch JR. The 22q11.2 Low Copy Repeats. Genes (Basel) 2022; 13:2101. [PMID: 36421776 PMCID: PMC9690962 DOI: 10.3390/genes13112101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 10/19/2022] [Accepted: 10/25/2022] [Indexed: 07/22/2023] Open
Abstract
LCR22s are among the most complex loci in the human genome and are susceptible to nonallelic homologous recombination. This can lead to a variety of genomic disorders, including deletions, duplications, and translocations, of which the 22q11.2 deletion syndrome is the most common in humans. Interrogating these phenomena is difficult due to the high complexity of the LCR22s and the inaccurate representation of the LCRs across different reference genomes. Optical mapping techniques, which provide long-range chromosomal maps, could be used to unravel the complex duplicon structure. These techniques have already uncovered the hypervariability of the LCR22-A haplotype in the human population. Although optical LCR22 mapping is a major step forward, long-read sequencing approaches will be essential to reach nucleotide resolution of the LCR22s and map the crossover sites. Accurate maps and sequences are needed to pinpoint potential predisposing alleles and, most importantly, allow for genotype-phenotype studies exploring the role of the LCR22s in health and disease. In addition, this research might provide a paradigm for the study of other rare genomic disorders.
Collapse
|