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Wang Y, Zhai Y, Zhang M, Song C, Zhang Y, Zhang G. Escaping from CRISPR-Cas-mediated knockout: the facts, mechanisms, and applications. Cell Mol Biol Lett 2024; 29:48. [PMID: 38589794 PMCID: PMC11003099 DOI: 10.1186/s11658-024-00565-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2023] [Accepted: 03/21/2024] [Indexed: 04/10/2024] Open
Abstract
Clustered regularly interspaced short palindromic repeats and associated Cas protein (CRISPR-Cas), a powerful genome editing tool, has revolutionized gene function investigation and exhibits huge potential for clinical applications. CRISPR-Cas-mediated gene knockout has already become a routine method in research laboratories. However, in the last few years, accumulating evidences have demonstrated that genes knocked out by CRISPR-Cas may not be truly silenced. Functional residual proteins could be generated in such knockout organisms to compensate the putative loss of function, termed herein knockout escaping. In line with this, several CRISPR-Cas-mediated knockout screenings have discovered much less abnormal phenotypes than expected. How does knockout escaping happen and how often does it happen have not been systematically reviewed yet. Without knowing this, knockout results could easily be misinterpreted. In this review, we summarize these evidences and propose two main mechanisms allowing knockout escaping. To avoid the confusion caused by knockout escaping, several strategies are discussed as well as their advantages and disadvantages. On the other hand, knockout escaping also provides convenient tools for studying essential genes and treating monogenic disorders such as Duchenne muscular dystrophy, which are discussed in the end.
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Affiliation(s)
- Ying Wang
- The Cancer Institute, The Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, China
- School of Public Health, Qingdao University, Qingdao, China
| | - Yujing Zhai
- The Cancer Institute, The Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, China
- School of Public Health, Qingdao University, Qingdao, China
| | - Mingzhe Zhang
- The Cancer Institute, The Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, China
| | - Chunlin Song
- The Cancer Institute, The Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, China
| | - Yuqing Zhang
- The Cancer Institute, The Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, China
| | - Gang Zhang
- The Cancer Institute, The Affiliated Hospital of Qingdao University, Qingdao University, Qingdao, China.
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2
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Sanoguera-Miralles L, Llinares-Burguet I, Bueno-Martínez E, Ramadane-Morchadi L, Stuani C, Valenzuela-Palomo A, García-Álvarez A, Pérez-Segura P, Buratti E, de la Hoya M, Velasco-Sampedro EA. Comprehensive splicing analysis of the alternatively spliced CHEK2 exons 8 and 10 reveals three enhancer/silencer-rich regions and 38 spliceogenic variants. J Pathol 2024; 262:395-409. [PMID: 38332730 DOI: 10.1002/path.6243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 10/26/2023] [Accepted: 11/28/2023] [Indexed: 02/10/2024]
Abstract
Splicing is controlled by a large set of regulatory elements (SREs) including splicing enhancers and silencers, which are involved in exon recognition. Variants at these motifs may dysregulate splicing and trigger loss-of-function transcripts associated with disease. Our goal here was to study the alternatively spliced exons 8 and 10 of the breast cancer susceptibility gene CHEK2. For this purpose, we used a previously published minigene with exons 6-10 that produced the expected minigene full-length transcript and replicated the naturally occurring events of exon 8 [Δ(E8)] and exon 10 [Δ(E10)] skipping. We then introduced 12 internal microdeletions of exons 8 and 10 by mutagenesis in order to map SRE-rich intervals by splicing assays in MCF-7 cells. We identified three minimal (10-, 11-, 15-nt) regions essential for exon recognition: c.863_877del [ex8, Δ(E8): 75%] and c.1073_1083del and c.1083_1092del [ex10, Δ(E10): 97% and 62%, respectively]. Then 87 variants found within these intervals were introduced into the wild-type minigene and tested functionally. Thirty-eight of them (44%) impaired splicing, four of which (c.883G>A, c.883G>T, c.884A>T, and c.1080G>T) induced negligible amounts (<5%) of the minigene full-length transcript. Another six variants (c.886G>A, c.886G>T, c.1075G>A, c.1075G>T, c.1076A>T, and c.1078G>T) showed significantly strong impacts (20-50% of the minigene full-length transcript). Thirty-three of the 38 spliceogenic variants were annotated as missense, three as nonsense, and two as synonymous, underlying the fact that any exonic change is capable of disrupting splicing. Moreover, c.883G>A, c.883G>T, and c.884A>T were classified as pathogenic/likely pathogenic variants according to ACMG/AMP (American College of Medical Genetics and Genomics/Association for Molecular Pathology)-based criteria. © 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.
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Affiliation(s)
- Lara Sanoguera-Miralles
- Splicing and Genetic Susceptibility to Cancer, Unidad de Excelencia Instituto de Biomedicina y Genética Molecular de Valladolid (IBGM), Consejo Superior de Investigaciones Científicas - Universidad de Valladolid (CSIC-UVa), Valladolid, Spain
| | - Inés Llinares-Burguet
- Splicing and Genetic Susceptibility to Cancer, Unidad de Excelencia Instituto de Biomedicina y Genética Molecular de Valladolid (IBGM), Consejo Superior de Investigaciones Científicas - Universidad de Valladolid (CSIC-UVa), Valladolid, Spain
| | - Elena Bueno-Martínez
- Splicing and Genetic Susceptibility to Cancer, Unidad de Excelencia Instituto de Biomedicina y Genética Molecular de Valladolid (IBGM), Consejo Superior de Investigaciones Científicas - Universidad de Valladolid (CSIC-UVa), Valladolid, Spain
| | - Lobna Ramadane-Morchadi
- Molecular Oncology Laboratory CIBERONC, Hospital Clínico San Carlos, IdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos), Madrid, Spain
| | - Cristiana Stuani
- Molecular Pathology Lab. International Centre of Genetic Engineering and Biotechnology, Trieste, Italy
| | - Alberto Valenzuela-Palomo
- Splicing and Genetic Susceptibility to Cancer, Unidad de Excelencia Instituto de Biomedicina y Genética Molecular de Valladolid (IBGM), Consejo Superior de Investigaciones Científicas - Universidad de Valladolid (CSIC-UVa), Valladolid, Spain
| | - Alicia García-Álvarez
- Splicing and Genetic Susceptibility to Cancer, Unidad de Excelencia Instituto de Biomedicina y Genética Molecular de Valladolid (IBGM), Consejo Superior de Investigaciones Científicas - Universidad de Valladolid (CSIC-UVa), Valladolid, Spain
| | - Pedro Pérez-Segura
- Molecular Oncology Laboratory CIBERONC, Hospital Clínico San Carlos, IdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos), Madrid, Spain
| | - Emanuele Buratti
- Molecular Pathology Lab. International Centre of Genetic Engineering and Biotechnology, Trieste, Italy
| | - Miguel de la Hoya
- Molecular Oncology Laboratory CIBERONC, Hospital Clínico San Carlos, IdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos), Madrid, Spain
| | - Eladio A Velasco-Sampedro
- Splicing and Genetic Susceptibility to Cancer, Unidad de Excelencia Instituto de Biomedicina y Genética Molecular de Valladolid (IBGM), Consejo Superior de Investigaciones Científicas - Universidad de Valladolid (CSIC-UVa), Valladolid, Spain
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3
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Wang X, Zhang H, Huang H, Wang W, Wen Y, Dai Z, Huang S, Zhou J, Zhou Y. Functional and structural analysis of a novel splice site HMBS variant in a Chinese AIP patient. Front Genet 2023; 14:1333111. [PMID: 38192441 PMCID: PMC10773753 DOI: 10.3389/fgene.2023.1333111] [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: 11/04/2023] [Accepted: 12/07/2023] [Indexed: 01/10/2024] Open
Abstract
Background: Acute intermittent porphyria (AIP) is a rare metabolic disorder that results from mutations in the gene encoding hydroxymethylbilane synthase (HMBS), an enzyme involved in heme biosynthesis. AIP follows an autosomal dominant inheritance pattern, but most carriers are asymptomatic. The clinical manifestations of AIP include acute attacks of abdominal pain and neuropsychiatric disturbances. The pathogenicity of novel HMBS variants identified in Chinese patients has not been well established. Objective: The article aims to identify the pathogenic mutation in an AIP patient and prove its pathogenicity through in vitro experiments. Methods: A 22-year-old female diagnosed with AIP participated in the study. Variant screening of her HMBS gene was carried out through Sanger sequencing. To ascertain the consequences of the newly discovered variant, we conducted in vitro experimentation targeting HMBS gene expression and enzymatic function. Additionally, protein structure analysis was performed. Cycloheximide treatment and UPF1-specific siRNA knockdown were employed to assess the impact of the mutation on the mechanism of non-sense-mediated mRNA decay (NMD). Results: A novel splice site variant in the HMBS gene (c.648_651+1delCCAGG) was detected in the patient, which caused aberrant mRNA splicing. In vitro experiments demonstrated that this variant significantly decreased the expression of HMBS. Further investigation confirmed that this decrease was due to NMD. Additionally, structural analysis indicated that this variant would destabilize the HMBS protein and impair its catalytic activity. To gain a comprehensive understanding of HMBS mutations in the context of AIP, we conducted a literature search on PubMed using the keywords 'HMBS' and 'Acute intermittent porphyria' from 2013 to 2023. This search yielded 19 clinical case reports written in English, which collectively described 220 HMBS gene mutations worldwide. Conclusion: The study identified and proved the pathogenicity of a novel splice site HMBS variant for the first time. Our results elucidated the pathological mechanism by which this mutation causes AIP through reducing HMBS expression and activity. These findings provide theoretical guidance for the diagnosis, treatment and genetic counseling of AIP patients.
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Affiliation(s)
- Xiaoqing Wang
- Dongguan Hospital, Guangzhou University of Chinese Medicine, Dongguan, Guangdong Province, China
| | - Huifen Zhang
- Department of Endocrinology, Dongguan Hospital of Guangzhou University of Chinese Medicine, Dongguan, Guangdong Province, China
| | - Huanhuan Huang
- Dongguan Hospital, Guangzhou University of Chinese Medicine, Dongguan, Guangdong Province, China
| | - Wenli Wang
- Dongguan Hospital, Guangzhou University of Chinese Medicine, Dongguan, Guangdong Province, China
| | - Yuping Wen
- Dongguan Hospital, Guangzhou University of Chinese Medicine, Dongguan, Guangdong Province, China
| | - Zhuojin Dai
- The First Clinical Medical College, Guangdong Medical University, Zhanjiang, Guangdong Province, China
| | - Shuling Huang
- Department of Endocrinology, Dongguan Hospital of Guangzhou University of Chinese Medicine, Dongguan, Guangdong Province, China
| | - Jingyi Zhou
- Dongguan Hospital, Guangzhou University of Chinese Medicine, Dongguan, Guangdong Province, China
| | - Yuqing Zhou
- Department of Endocrinology, Dongguan Hospital of Guangzhou University of Chinese Medicine, Dongguan, Guangdong Province, China
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Klein J, Allister AB, Schmidt G, Otto A, Heinecke K, Bax-Knoche J, Beger C, Becker S, Bartels S, Ripperger T, Bohne J, Dörk T, Schlegelberger B, Hofmann W, Steinemann D. A Novel Alu Element Insertion in ATM Induces Exon Skipping in Suspected HBOC Patients. Hum Mutat 2023. [DOI: 10.1155/2023/6623515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023]
Abstract
The vast majority of patients at risk of hereditary breast and/or ovarian cancer (HBOC) syndrome remain without a molecular diagnosis after routine genetic testing. One type of genomic alteration that is commonly missed by diagnostic pipelines is mobile element insertions (MEIs). Here, we reanalyzed multigene panel data from suspected HBOC patients using the MEI detection tool Mobster. A novel Alu element insertion in ATM intron 54 (ATM:c.8010+30_8010+31insAluYa5) was identified as a potential contributing factor in seven patients. Transcript analysis of patient-derived RNA from three heterozygous carriers revealed exon 54 skipping in 38% of total ATM transcripts. To manifest the direct association between the Alu element insertion and the aberrant splice pattern, HEK293T and MCF7 cells were transfected with wild-type or Alu element-carrying minigene constructs. On average, 77% of plasmid-derived transcripts lacked exon 54 in the presence of the Alu element insertion compared to only 4.7% of transcripts expressed by the wild-type minigene. These results strongly suggest ATM:c.8010+30_8010+31insAluYa5 as the main driver of ATM exon 54 skipping. Since this exon loss is predicted to cause a frameshift and a premature stop codon, mutant transcripts are unlikely to translate into functional proteins. Based on its estimated frequency of up to 0.05% in control populations, we propose to consider ATM:c.8010+30_8010+31insAluYa5 in suspected HBOC patients and to clarify its role in carcinogenesis through future epidemiological and functional analyses. Generally, the implementation of MEI detection tools in diagnostic sequencing pipelines could increase the diagnostic yield, as MEIs are likely underestimated contributors to genetic diseases.
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Affiliation(s)
- Janin Klein
- Department of Human Genetics, Hannover Medical School, Hannover, Germany
| | | | - Gunnar Schmidt
- Department of Human Genetics, Hannover Medical School, Hannover, Germany
| | - Annette Otto
- Department of Human Genetics, Hannover Medical School, Hannover, Germany
| | - Kai Heinecke
- MVZ Labor Krone GbR, Bad Salzuflen, Bielefeld, Germany
| | | | - Carmela Beger
- MVZ Labor Krone GbR, Bad Salzuflen, Bielefeld, Germany
| | - Sarah Becker
- MVZ Labor Krone GbR, Bad Salzuflen, Bielefeld, Germany
| | - Stephan Bartels
- Department of Pathology, Hannover Medical School, Hannover, Germany
| | - Tim Ripperger
- Department of Human Genetics, Hannover Medical School, Hannover, Germany
| | - Jens Bohne
- Department of Virology, Hannover Medical School, Hannover, Germany
| | - Thilo Dörk
- Department of Gynaecology and Obstetrics, Hannover Medical School, Hannover, Germany
| | | | - Winfried Hofmann
- Department of Human Genetics, Hannover Medical School, Hannover, Germany
| | - Doris Steinemann
- Department of Human Genetics, Hannover Medical School, Hannover, Germany
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Núñez-Moreno G, Tamayo A, Ruiz-Sánchez C, Cortón M, Mínguez P. VIsoQLR: an interactive tool for the detection, quantification and fine-tuning of isoforms in selected genes using long-read sequencing. Hum Genet 2023; 142:495-506. [PMID: 36881176 DOI: 10.1007/s00439-023-02539-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 02/23/2023] [Indexed: 03/08/2023]
Abstract
DNA variants altering the pre-mRNA splicing process represent an underestimated cause of human genetic diseases. Their association with disease traits should be confirmed using functional assays from patient cell lines or alternative models to detect aberrant mRNAs. Long-read sequencing is a suitable technique to identify and quantify mRNA isoforms. Available isoform detection and/or quantification tools are generally designed for the whole transcriptome analysis. However experiments focusing on genes of interest need more precise data fine-tuning and visualization tools.Here we describe VIsoQLR, an interactive analyzer, viewer and editor for the semi-automated identification and quantification of known and novel isoforms using long-read sequencing data. VIsoQLR is tailored to thoroughly analyze mRNA expression in splicing assays of selected genes. Our tool takes sequences aligned to a reference, and for each gene, it defines consensus splice sites and quantifies isoforms. VIsoQLR introduces features to edit the splice sites through dynamic and interactive graphics and tables, allowing accurate manual curation. Known isoforms detected by other methods can also be imported as references for comparison. A benchmark against two other popular transcriptome-based tools shows VIsoQLR accurate performance on both detection and quantification of isoforms. Here, we present VIsoQLR principles and features and its applicability in a case study example using nanopore-based long-read sequencing. VIsoQLR is available at https://github.com/TBLabFJD/VIsoQLR .
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Affiliation(s)
- Gonzalo Núñez-Moreno
- Department of Genetics and Genomics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.
- Bioinformatics Unit, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.
- Center for Biomedical Network Research On Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain.
| | - Alejandra Tamayo
- Department of Genetics and Genomics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
- Center for Biomedical Network Research On Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
- Department of Surgery, Medical and Social Sciences, Faculty of Medicine and Health Sciences, Science and Technology Campus, University of Alcalá, 28871, Alcalá de Henares, Spain
| | - Carolina Ruiz-Sánchez
- Department of Genetics and Genomics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
| | - Marta Cortón
- Department of Genetics and Genomics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
- Center for Biomedical Network Research On Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Pablo Mínguez
- Department of Genetics and Genomics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
- Bioinformatics Unit, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
- Center for Biomedical Network Research On Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
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6
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Shi X, Wang H, Zhang R, Liu Z, Guo W, Wang S, Liu X, Lang Y, Bottillo I, Dong B, Shao L. Minigene splicing assays reveal new insights into exonic variants of the SLC12A3 gene in Gitelman syndrome. Mol Genet Genomic Med 2023; 11:e2128. [PMID: 36597580 PMCID: PMC10094094 DOI: 10.1002/mgg3.2128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 09/15/2022] [Accepted: 12/15/2022] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Gitelman syndrome (GS) is a type of salt-losing tubular disease, most of which is caused by SLC12A3 gene variants, and missense variants account for the majority. Recently, the phenomenon of exon skipping, in which variants disrupt normal pre-mRNA splicing, has been related to a variety of diseases. Therefore, we hypothesize that a certain proportion of SLC12A3 variants can result in disease via interfering with the normal splicing process. METHODS We analyzed 342 previously presumed SLC12A3 missense variants using bioinformatics programs and identified candidate variants that may alter the splicing of pre-mRNA through minigene assays. RESULTS Our study revealed that, among ten candidate variants, six variants (c.602G>A, c.602G>T, c.1667C>T, c.1925G>A, c.2548G>C, and c.2549G>C) led to complete or incomplete exon skipping by affecting exonic splicing regulatory elements and/or disturbing canonical splice sites. CONCLUSION It is worth mentioning that this is the largest study on pre-mRNA splicing of SLC12A3 exonic variants. In addition, our study emphasizes the importance of detecting splicing function at the mRNA level in GS and indicates that minigene analysis is a valuable tool for splicing functional assays of variants in vitro.
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Affiliation(s)
- Xiaomeng Shi
- Department of Nephrology, the Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China
| | - Hong Wang
- Department of Nephrology, Qingdao Eighth People's Hospital, Qingdao, China
| | - Ruixiao Zhang
- Department of Nephrology, the Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China
| | - Zhiying Liu
- Department of Nephrology, the Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China
| | - Wencong Guo
- Department of Nephrology, the Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China
| | - Sai Wang
- Department of Nephrology, the Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China.,Department of Dermatology, Peking University First Hospital, Beijing, China
| | - Xuyan Liu
- Department of Nephrology, the Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China
| | - Yanhua Lang
- Department of Nephrology, the Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China
| | - Irene Bottillo
- Division of Medical Genetics, Department of Molecular Medicine, Sapienza University, San Camillo-Forlanini Hospital, Rome, Italy
| | - Bingzi Dong
- Department of Endocrinology, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Leping Shao
- Department of Nephrology, the Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China
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7
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Valenzuela-Palomo A, Sanoguera-Miralles L, Bueno-Martínez E, Esteban-Sánchez A, Llinares-Burguet I, García-Álvarez A, Pérez-Segura P, Gómez-Barrero S, de la Hoya M, Velasco-Sampedro EA. Splicing Analysis of 16 PALB2 ClinVar Variants by Minigene Assays: Identification of Six Likely Pathogenic Variants. Cancers (Basel) 2022; 14:cancers14184541. [PMID: 36139699 PMCID: PMC9496955 DOI: 10.3390/cancers14184541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 09/12/2022] [Accepted: 09/15/2022] [Indexed: 11/29/2022] Open
Abstract
PALB2 loss-of-function variants are associated with significant increased risk of breast cancer as well as other types of tumors. Likewise, splicing disruptions are a common mechanism of disease susceptibility. Indeed, we previously showed, by minigene assays, that 35 out of 42 PALB2 variants impaired splicing. Taking advantage of one of these constructs (mgPALB2_ex1-3), we proceeded to analyze other variants at exons 1 to 3 reported at the ClinVar database. Thirty-one variants were bioinformatically analyzed with MaxEntScan and SpliceAI. Then, 16 variants were selected for subsequent RNA assays. We identified a total of 12 spliceogenic variants, 11 of which did not produce any trace of the expected minigene full-length transcript. Interestingly, variant c.49-1G > A mimicked previous outcomes in patient RNA (transcript ∆(E2p6)), supporting the reproducibility of the minigene approach. A total of eight variant-induced transcripts were characterized, three of which (∆(E1q17), ∆(E3p11), and ∆(E3)) were predicted to introduce a premature termination codon and to undergo nonsense-mediated decay, and five (▼(E1q9), ∆(E2p6), ∆(E2), ▼(E3q48)-a, and ▼(E3q48)-b) maintained the reading frame. According to an ACMG/AMP (American College of Medical Genetics and Genomics/Association for Molecular Pathology)-based classification scheme, which integrates mgPALB2 data, six PALB2 variants were classified as pathogenic/likely pathogenic, five as VUS, and five as likely benign. Furthermore, five ±1,2 variants were catalogued as VUS because they produced significant proportions of in-frame transcripts of unknown impact on protein function.
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Affiliation(s)
- Alberto Valenzuela-Palomo
- Splicing and Genetic Susceptibility to Cancer, Unidad de Excelencia Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC-UVa), 47003 Valladolid, Spain
| | - Lara Sanoguera-Miralles
- Splicing and Genetic Susceptibility to Cancer, Unidad de Excelencia Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC-UVa), 47003 Valladolid, Spain
| | - Elena Bueno-Martínez
- Splicing and Genetic Susceptibility to Cancer, Unidad de Excelencia Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC-UVa), 47003 Valladolid, Spain
| | - Ada Esteban-Sánchez
- Molecular Oncology Laboratory, Hospital Clínico San Carlos, IdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos), 28040 Madrid, Spain
| | - Inés Llinares-Burguet
- Splicing and Genetic Susceptibility to Cancer, Unidad de Excelencia Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC-UVa), 47003 Valladolid, Spain
| | - Alicia García-Álvarez
- Splicing and Genetic Susceptibility to Cancer, Unidad de Excelencia Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC-UVa), 47003 Valladolid, Spain
| | - Pedro Pérez-Segura
- Molecular Oncology Laboratory, Hospital Clínico San Carlos, IdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos), 28040 Madrid, Spain
| | - Susana Gómez-Barrero
- Facultad de Ciencias de la Salud, Universidad Alfonso X “El Sabio”, Avda. de la Universidad 1, Villanueva de la Cañada, 28691 Madrid, Spain
| | - Miguel de la Hoya
- Molecular Oncology Laboratory, Hospital Clínico San Carlos, IdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos), 28040 Madrid, Spain
| | - Eladio A. Velasco-Sampedro
- Splicing and Genetic Susceptibility to Cancer, Unidad de Excelencia Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC-UVa), 47003 Valladolid, Spain
- Correspondence:
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8
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Zhang H, Chen C, Wu X, Lou C, Liang Q, Wu W, Wang X, Ding Q. Effects of 14 F9 synonymous codon variants on hemophilia B expression: Alteration of splicing along with protein expression. Hum Mutat 2022; 43:928-939. [PMID: 35391506 DOI: 10.1002/humu.24377] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 03/30/2022] [Accepted: 03/31/2022] [Indexed: 01/25/2023]
Abstract
There is growing evidence that synonymous codon variants (SCVs) can cause disease through the disruption of different processes of protein production. The aim of the study is to investigate whether the 14 SCVs reported in the F9 variant database were the pathogenic causes of hemophilia B. The impacts of SCVs on splicing and protein expression were detected using a combination of in silico prediction, in vitro minigene splicing assay and cell expression detection. The splicing transcripts were identified and quantified by co-amplification fluorescent PCR. The mechanism of splicing was verified by a modified pU1snRNA and pU7snRNA approach. Aberrant splicing patterns were found in eight SCVs. Five of the 8 SCVs produced almost all aberrant splicing isoforms, which were expected to truncate protein, three of them presented a partial defect on both splicing and protein secretion, the overall effects were consistent with the residual Factor IX activity of the affected cases. Neither the pre-messenger RNA (mRNA) splicing process nor the protein function was impaired in the rest six SCVs. In conclusion, our study firstly revealed the pathogenic mechanism of the 14 F9 SCVs and highlighted the importance of performing mRNA splicing analysis and protein expression studies of SCVs in inherited disorders.
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Affiliation(s)
- Huayang Zhang
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Changming Chen
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Xi Wu
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Can Lou
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Qian Liang
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Wenman Wu
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- Collaborative Innovation Center of Hematology, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Xuefeng Wang
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- Collaborative Innovation Center of Hematology, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Qiulan Ding
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- Collaborative Innovation Center of Hematology, Shanghai Jiaotong University School of Medicine, Shanghai, China
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9
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Minigene Splicing Assays Identify 20 Spliceogenic Variants of the Breast/Ovarian Cancer Susceptibility Gene RAD51C. Cancers (Basel) 2022; 14:cancers14122960. [PMID: 35740625 PMCID: PMC9221245 DOI: 10.3390/cancers14122960] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 06/14/2022] [Accepted: 06/14/2022] [Indexed: 12/11/2022] Open
Abstract
RAD51C loss-of-function variants are associated with an increased risk of breast and ovarian cancers. Likewise, splicing disruptions are a frequent mechanism of gene inactivation. Taking advantage of a previous splicing-reporter minigene with exons 2-8 (mgR51C_ex2-8), we proceeded to check its impact on the splicing of candidate ClinVar variants. A total of 141 RAD51C variants at the intron/exon boundaries were analyzed with MaxEntScan. Twenty variants were selected and genetically engineered into the wild-type minigene. All the variants disrupted splicing, and 18 induced major splicing anomalies without any trace or minimal amounts (<2.4%) of the minigene full-length (FL) transcript. Twenty-seven transcripts (including the wild-type and r.904A FL transcripts) were identified by fluorescent fragment electrophoresis; of these, 14 were predicted to truncate the RAD51C protein, 3 kept the reading frame, and 8 minor isoforms (1.1−4.7% of the overall expression) could not be characterized. Finally, we performed a tentative interpretation of the variants according to an ACMG/AMP (American College of Medical Genetics and Genomics/Association for Molecular Pathology)-based classification scheme, classifying 16 variants as likely pathogenic. Minigene assays have been proven as valuable tools for the initial characterization of potential spliceogenic variants. Hence, minigene mgR51C_ex2-8 provided useful splicing data for 40 RAD51C variants.
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10
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Covello G, Ibrahim GH, Bacchi N, Casarosa S, Denti MA. Exon Skipping Through Chimeric Antisense U1 snRNAs to Correct Retinitis Pigmentosa GTPase-Regulator ( RPGR) Splice Defect. Nucleic Acid Ther 2022; 32:333-349. [PMID: 35166581 PMCID: PMC9416563 DOI: 10.1089/nat.2021.0053] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Inherited retinal dystrophies are caused by mutations in more than 250 genes, each of them carrying several types of mutations that can lead to different clinical phenotypes. Mutations in Retinitis Pigmentosa GTPase-Regulator (RPGR) cause X-linked Retinitis pigmentosa (RP). A nucleotide substitution in intron 9 of RPGR causes the increase of an alternatively spliced isoform of the mature mRNA, bearing exon 9a (E9a). This introduces a stop codon, leading to truncation of the protein. Aiming at restoring impaired gene expression, we developed an antisense RNA-based therapeutic approach for the skipping of RPGR E9a. We designed a set of specific U1 antisense snRNAs (U1_asRNAs) and tested their efficacy in vitro, upon transient cotransfection with RPGR minigene reporter systems in HEK-293T, 661W, and PC-12 cell lines.
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Affiliation(s)
- Giuseppina Covello
- RNA Biology and Biotechnology Laboratory, Department of Cellular, Computational and Integrative Biology - CIBIO, University of Trento, Trento, Italy
| | - Gehan H Ibrahim
- Department of Medical Biochemistry, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | - Niccolò Bacchi
- RNA Biology and Biotechnology Laboratory, Department of Cellular, Computational and Integrative Biology - CIBIO, University of Trento, Trento, Italy
| | - Simona Casarosa
- Neural Development and Regeneration Laboratory, Department of Cellular, Computational and Integrative Biology - CIBIO, University of Trento, Trento, Italy.,Centre for Medical Science - CIS Med, University of Trento, Trento, Italy.,CNR Neuroscience Institute, Pisa, Italy
| | - Michela Alessandra Denti
- RNA Biology and Biotechnology Laboratory, Department of Cellular, Computational and Integrative Biology - CIBIO, University of Trento, Trento, Italy.,CNR Neuroscience Institute, Pisa, Italy
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11
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He WB, Xiao WJ, Dai CL, Wang YR, Li XR, Gong F, Meng LL, Tan C, Zeng SC, Lu GX, Lin G, Tan YQ, Hu H, Du J. RNA splicing analysis contributes to reclassifying variants of uncertain significance and improves the diagnosis of monogenic disorders. J Med Genet 2022; 59:1010-1016. [PMID: 35121647 DOI: 10.1136/jmedgenet-2021-108013] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 01/06/2022] [Indexed: 11/04/2022]
Abstract
BACKGROUND Numerous variants of uncertain significance (VUSs) have been identified by whole exome sequencing in clinical practice. However, VUSs are not currently considered medically actionable. OBJECTIVE To assess the splicing patterns of 49 VUSs in 48 families identified clinically to improve genetic counselling and family planning. METHODS Forty-nine participants with 49 VUSs were recruited from the Reproductive and Genetic Hospital of CITIC-Xiangya. Bioinformatic analysis was performed to preliminarily predict the splicing effects of these VUSs. RT-PCR and minigene analysis were used to assess the splicing patterns of the VUSs. According to the results obtained, couples opted for different methods of reproductive interventions to conceive a child, including prenatal diagnosis and preimplantation genetic testing (PGT). RESULTS Eleven variants were found to alter pre-mRNA splicing and one variant caused nonsense-mediated mRNA decay, which resulted in the reclassification of these VUSs as likely pathogenic. One couple chose to undergo in vitro fertilisation with PGT treatment; a healthy embryo was transferred and the pregnancy is ongoing. Three couples opted for natural pregnancy with prenatal diagnosis. One couple terminated the pregnancy because the fetus was affected by short-rib thoracic dysplasia and harboured the related variant. The infants of the other two couples were born and were healthy at their last recorded follow-up. CONCLUSION RNA splicing analysis is an important method to assess the impact of sequence variants on splicing in clinical practice and can contribute to the reclassification of a significant proportion of VUSs. RNA splicing analysis should be considered for genetic disease diagnostics.
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Affiliation(s)
- Wen-Bin He
- Institute of Reproductive and Stem Cell Engineering, School of Basic Medical Science, Central South University, Changsha, Hunan, China.,National Engineering and Research Center of Human Stem Cells, Changsha, Hunan, China.,Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, Hunan, China.,Clinical Research Center For Reproduction and Genetics In Hunan Province, Changsha, China
| | - Wen-Juan Xiao
- National Engineering and Research Center of Human Stem Cells, Changsha, Hunan, China.,Hunan Guangxiu Hospital, Medical College of Hunan Normal University, Changsha, Hunan, China
| | - Cong-Ling Dai
- Institute of Reproductive and Stem Cell Engineering, School of Basic Medical Science, Central South University, Changsha, Hunan, China.,National Engineering and Research Center of Human Stem Cells, Changsha, Hunan, China.,Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, Hunan, China.,Clinical Research Center For Reproduction and Genetics In Hunan Province, Changsha, China
| | - Yu-Rong Wang
- Hunan Guangxiu Hospital, Medical College of Hunan Normal University, Changsha, Hunan, China
| | - Xiu-Rong Li
- Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, Hunan, China.,Clinical Research Center For Reproduction and Genetics In Hunan Province, Changsha, China
| | - Fei Gong
- Institute of Reproductive and Stem Cell Engineering, School of Basic Medical Science, Central South University, Changsha, Hunan, China.,National Engineering and Research Center of Human Stem Cells, Changsha, Hunan, China.,Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, Hunan, China.,Clinical Research Center For Reproduction and Genetics In Hunan Province, Changsha, China
| | - Lan-Lan Meng
- Institute of Reproductive and Stem Cell Engineering, School of Basic Medical Science, Central South University, Changsha, Hunan, China.,Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, Hunan, China
| | - Chen Tan
- Institute of Reproductive and Stem Cell Engineering, School of Basic Medical Science, Central South University, Changsha, Hunan, China
| | - Si-Cong Zeng
- Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, Hunan, China.,Hunan Guangxiu Hospital, Medical College of Hunan Normal University, Changsha, Hunan, China
| | - Guang-Xiu Lu
- National Engineering and Research Center of Human Stem Cells, Changsha, Hunan, China.,Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, Hunan, China.,Clinical Research Center For Reproduction and Genetics In Hunan Province, Changsha, China.,Hunan Guangxiu Hospital, Medical College of Hunan Normal University, Changsha, Hunan, China
| | - Ge Lin
- Institute of Reproductive and Stem Cell Engineering, School of Basic Medical Science, Central South University, Changsha, Hunan, China.,National Engineering and Research Center of Human Stem Cells, Changsha, Hunan, China.,Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, Hunan, China.,Clinical Research Center For Reproduction and Genetics In Hunan Province, Changsha, China
| | - Yue-Qiu Tan
- Institute of Reproductive and Stem Cell Engineering, School of Basic Medical Science, Central South University, Changsha, Hunan, China.,National Engineering and Research Center of Human Stem Cells, Changsha, Hunan, China.,Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, Hunan, China.,Clinical Research Center For Reproduction and Genetics In Hunan Province, Changsha, China.,Hunan Guangxiu Hospital, Medical College of Hunan Normal University, Changsha, Hunan, China
| | - Hao Hu
- Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, Hunan, China .,Clinical Research Center For Reproduction and Genetics In Hunan Province, Changsha, China
| | - Juan Du
- Institute of Reproductive and Stem Cell Engineering, School of Basic Medical Science, Central South University, Changsha, Hunan, China .,National Engineering and Research Center of Human Stem Cells, Changsha, Hunan, China.,Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, Hunan, China.,Clinical Research Center For Reproduction and Genetics In Hunan Province, Changsha, China
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12
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Zhu L, Miao B, Dymerska D, Kuswik M, Bueno-Martínez E, Sanoguera-Miralles L, Velasco EA, Paramasivam N, Schlesner M, Kumar A, Yuan Y, Lubinski J, Bandapalli OR, Hemminki K, Försti A. Germline Variants of CYBA and TRPM4 Predispose to Familial Colorectal Cancer. Cancers (Basel) 2022; 14:cancers14030670. [PMID: 35158942 PMCID: PMC8833488 DOI: 10.3390/cancers14030670] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 01/17/2022] [Accepted: 01/26/2022] [Indexed: 02/07/2023] Open
Abstract
Simple Summary Whole-genome sequencing and bioinformatics analysis on unique colorectal cancer families revealed two attractive candidate predisposition genes, CYBA and TRPM4, each with a loss-of-function variant. Supported by our functional studies, we suggest that the two gene defects mechanistically involve intestinal barrier integrity through reactive oxygen species and mucus biology, which converges in chronic bowel inflammation, a known risk factor for colorectal cancer. Abstract Familial colorectal cancer (CRC) is only partially explained by known germline predisposing genes. We performed whole-genome sequencing in 15 Polish families of many affected individuals, without mutations in known CRC predisposing genes. We focused on loss-of-function variants and functionally characterized them. We identified a frameshift variant in the CYBA gene (c.246delC) in one family and a splice site variant in the TRPM4 gene (c.25–1 G > T) in another family. While both variants were absent or extremely rare in gene variant databases, we identified four additional Polish familial CRC cases and two healthy elderly individuals with the CYBA variant (odds ratio 2.46, 95% confidence interval 0.48–12.69). Both variants led to a premature stop codon and to a truncated protein. Functional characterization of the variants showed that knockdown of CYBA or TRPM4 depressed generation of reactive oxygen species (ROS) in LS174T and HT-29 cell lines. Knockdown of TRPM4 resulted in decreased MUC2 protein production. CYBA encodes a component in the NADPH oxidase system which generates ROS and controls, e.g., bacterial colonization in the gut. Germline CYBA variants are associated with early onset inflammatory bowel disease, supported with experimental evidence on loss of intestinal mucus barrier function due to ROS deficiency. TRPM4 encodes a calcium-activated ion channel, which, in a human colonic cancer cell line, controls calcium-mediated secretion of MUC2, a major component of intestinal mucus barrier. We suggest that the gene defects in CYBA and TRPM4 mechanistically involve intestinal barrier integrity through ROS and mucus biology, which converges in chronic bowel inflammation.
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Affiliation(s)
- Lizhen Zhu
- Division of Molecular Genetic Epidemiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 580, D-69120 Heidelberg, Germany; (L.Z.); (B.M.); (A.K.); (A.F.)
- Department of Medical Oncology, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou 310009, China;
| | - Beiping Miao
- Division of Molecular Genetic Epidemiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 580, D-69120 Heidelberg, Germany; (L.Z.); (B.M.); (A.K.); (A.F.)
- Hopp Children’s Cancer Center (KiTZ), D-69120 Heidelberg, Germany
- Division of Pediatric Neurooncology, German Cancer Research Center (DKFZ), German Cancer Consortium (DKTK), D-69120 Heidelberg, Germany
| | - Dagmara Dymerska
- Department of Genetics and Pathology, Hereditary Cancer Center, Pomeranian Medical University, Unii Lubelskiej 1, 71-252 Szczecin, Poland; (D.D.); (M.K.); (J.L.)
| | - Magdalena Kuswik
- Department of Genetics and Pathology, Hereditary Cancer Center, Pomeranian Medical University, Unii Lubelskiej 1, 71-252 Szczecin, Poland; (D.D.); (M.K.); (J.L.)
| | - Elena Bueno-Martínez
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular (CSIC-UVa), 47003 Valladolid, Spain; (E.B.-M.); (L.S.-M.); (E.A.V.)
| | - Lara Sanoguera-Miralles
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular (CSIC-UVa), 47003 Valladolid, Spain; (E.B.-M.); (L.S.-M.); (E.A.V.)
| | - Eladio A. Velasco
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular (CSIC-UVa), 47003 Valladolid, Spain; (E.B.-M.); (L.S.-M.); (E.A.V.)
| | - Nagarajan Paramasivam
- Computational Oncology, Molecular Diagnostics Program, National Center for Tumor Diseases (NCT), D-69120 Heidelberg, Germany;
| | - Matthias Schlesner
- Bioinformatics and Omics Data Analytics, German Cancer Research Center (DKFZ), D-69120 Heidelberg, Germany;
| | - Abhishek Kumar
- Division of Molecular Genetic Epidemiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 580, D-69120 Heidelberg, Germany; (L.Z.); (B.M.); (A.K.); (A.F.)
- Institute of Bioinformatics, International Technology Park, Bengaluru 560066, India
- Manipal Academy of Higher Education (MAHE), Manipal 576104, India
| | - Ying Yuan
- Department of Medical Oncology, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou 310009, China;
| | - Jan Lubinski
- Department of Genetics and Pathology, Hereditary Cancer Center, Pomeranian Medical University, Unii Lubelskiej 1, 71-252 Szczecin, Poland; (D.D.); (M.K.); (J.L.)
| | - Obul Reddy Bandapalli
- Division of Molecular Genetic Epidemiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 580, D-69120 Heidelberg, Germany; (L.Z.); (B.M.); (A.K.); (A.F.)
- Hopp Children’s Cancer Center (KiTZ), D-69120 Heidelberg, Germany
- Division of Pediatric Neurooncology, German Cancer Research Center (DKFZ), German Cancer Consortium (DKTK), D-69120 Heidelberg, Germany
- Medical Faculty Heidelberg, Heidelberg University, D-69120 Heidelberg, Germany
- Correspondence: (O.R.B.); (K.H.)
| | - Kari Hemminki
- Division of Molecular Genetic Epidemiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 580, D-69120 Heidelberg, Germany; (L.Z.); (B.M.); (A.K.); (A.F.)
- Faculty of Medicine and Biomedical Center in Pilsen, Charles University in Prague, 30605 Pilsen, Czech Republic
- Division of Cancer Epidemiology, German Cancer Research Center (DKFZ), D-69120 Heidelberg, Germany
- Correspondence: (O.R.B.); (K.H.)
| | - Asta Försti
- Division of Molecular Genetic Epidemiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 580, D-69120 Heidelberg, Germany; (L.Z.); (B.M.); (A.K.); (A.F.)
- Hopp Children’s Cancer Center (KiTZ), D-69120 Heidelberg, Germany
- Division of Pediatric Neurooncology, German Cancer Research Center (DKFZ), German Cancer Consortium (DKTK), D-69120 Heidelberg, Germany
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13
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Li H, Engel C, de la Hoya M, Peterlongo P, Yannoukakos D, Livraghi L, Radice P, Thomassen M, Hansen TVO, Gerdes AM, Nielsen HR, Caputo SM, Zambelli A, Borg A, Solano A, Thomas A, Parsons MT, Antoniou AC, Leslie G, Yang X, Chenevix-Trench G, Caldes T, Kwong A, Pedersen IS, Lautrup CK, John EM, Terry MB, Hopper JL, Southey MC, Andrulis IL, Tischkowitz M, Janavicius R, Boonen SE, Kroeldrup L, Varesco L, Hamann U, Vega A, Palmero EI, Garber J, Montagna M, Van Asperen CJ, Foretova L, Greene MH, Selkirk T, Moller P, Toland AE, Domchek SM, James PA, Thorne H, Eccles DM, Nielsen SM, Manoukian S, Pasini B, Caligo MA, Lazaro C, Kirk J, Wappenschmidt B, Spurdle AB, Couch FJ, Schmutzler R, Goldgar DE. Risks of breast and ovarian cancer for women harboring pathogenic missense variants in BRCA1 and BRCA2 compared with those harboring protein truncating variants. Genet Med 2022; 24:119-129. [PMID: 34906479 PMCID: PMC10170303 DOI: 10.1016/j.gim.2021.08.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 07/22/2021] [Accepted: 08/25/2021] [Indexed: 12/20/2022] Open
Abstract
PURPOSE Germline genetic testing for BRCA1 and BRCA2 variants has been a part of clinical practice for >2 decades. However, no studies have compared the cancer risks associated with missense pathogenic variants (PVs) with those associated with protein truncating (PTC) variants. METHODS We collected 582 informative pedigrees segregating 1 of 28 missense PVs in BRCA1 and 153 pedigrees segregating 1 of 12 missense PVs in BRCA2. We analyzed 324 pedigrees with PTC variants in BRCA1 and 214 pedigrees with PTC variants in BRCA2. Cancer risks were estimated using modified segregation analysis. RESULTS Estimated breast cancer risks were markedly lower for women aged >50 years carrying BRCA1 missense PVs than for the women carrying BRCA1 PTC variants (hazard ratio [HR] = 3.9 [2.4-6.2] for PVs vs 12.8 [5.7-28.7] for PTC variants; P = .01), particularly for missense PVs in the BRCA1 C-terminal domain (HR = 2.8 [1.4-5.6]; P = .005). In case of BRCA2, for women aged >50 years, the HR was 3.9 (2.0-7.2) for those heterozygous for missense PVs compared with 7.0 (3.3-14.7) for those harboring PTC variants. BRCA1 p.[Cys64Arg] and BRCA2 p.[Trp2626Cys] were associated with particularly low risks of breast cancer compared with other PVs. CONCLUSION These results have important implications for the counseling of at-risk women who harbor missense PVs in the BRCA1/2 genes.
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Affiliation(s)
- Hongyan Li
- Cancer Control and Population Science, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT
| | - Christoph Engel
- Institute for Medical Informatics, Statistics and Epidemiology (IMISE), University of Leipzig, Leipzig, Germany
| | - Miguel de la Hoya
- Molecular Oncology Laboratory, CIBERONC, Hospital Clinico San Carlos, Instituto de Investigación Sanitaria San Carlos, Madrid, Spain
| | - Paolo Peterlongo
- Genome Diagnostics Program, IFOM - the FIRC Institute of Molecular Oncology, Milan, Italy
| | - Drakoulis Yannoukakos
- Molecular Diagnostics Laboratory, National Centre for Scientific Research "Demokritos", INRASTES Institute of Nuclear & Radiological Sciences & Technology, Energy & Safety, Athens, Greece
| | - Luca Livraghi
- Medical Oncology Unit, AZIENDA SOCIO SANITARIA TERRITORIALE PAPA GIOVANNI XXIII, Bergamo, Italy; University of Siena, Siena, Italy
| | - Paolo Radice
- Unit of Molecular Bases of Genetic Risk and Genetic Testing, Department of Research, Fondazione IRCCS Istituto Nazionale dei Tumori (INT), Milan, Italy
| | - Mads Thomassen
- Department of Clinical Genetics, Odense University Hospital, Odense, Denmark
| | - Thomas V O Hansen
- Department of Clinical Genetics, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Anne-Marie Gerdes
- Department of Clinical Genetics, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Henriette R Nielsen
- Department of Clinical Genetics Sygehus Lillebaelt, Vejle Hospital, Vejle, Denmark
| | - Sandrine M Caputo
- Service de Génétique, Institut Curie, Paris, France; Paris Sciences and Lettres Research University, Paris, France
| | - Alberto Zambelli
- Medical Oncology Unit, AZIENDA SOCIO SANITARIA TERRITORIALE PAPA GIOVANNI XXIII, Bergamo, Italy
| | - Ake Borg
- Divisions of Oncology and Pathology, Department of Clinical Sciences Lund, Lund University, Lund, Sweden
| | - Angela Solano
- INBIOMED, Faculty of Medicine, University of Buenos Aires, CONICET and Genotyping Laboratory, Department of Clinical Chemistry, CEMIC, Buenos Aires, Argentina
| | - Abigail Thomas
- Department of Health Sciences Research, Mayo Clinic, Rochester, MN
| | - Michael T Parsons
- Department of Genetics and Computational Biology, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - Antonis C Antoniou
- Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary Care, School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Goska Leslie
- Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary Care, School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Xin Yang
- Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary Care, School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Georgia Chenevix-Trench
- Department of Genetics and Computational Biology, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - Trinidad Caldes
- Molecular Oncology Laboratory, CIBERONC, Hospital Clinico San Carlos, Instituto de Investigación Sanitaria San Carlos, Madrid, Spain
| | - Ava Kwong
- Cancer Genetics Centre, Hong Kong Sanatorium & Hospital, Happy Valley, Hong Kong; Department of Surgery, LKS Faculty of Medicine,University of Hong Kong, Pok Fu Lam, Hong Kong
| | - Inge Søkilde Pedersen
- Molecular Diagnostics, Aalborg University Hospital, Aalborg, Denmark; Clinical Cancer Research Center and Department of Clinical Genetics, Aalborg University Hospital, Aalborg, Denmark; Department of Clinical Medicine, The Faculty of Medicine, Aalborg University of Aalborg, Aalborg, Denmark
| | - Charlotte K Lautrup
- Clinical Cancer Research Center and Department of Clinical Genetics, Aalborg University Hospital, Aalborg, Denmark; Department of Clinical Medicine, The Faculty of Medicine, Aalborg University of Aalborg, Aalborg, Denmark
| | - Esther M John
- Department of Epidemiology & Population Health and Stanford Cancer Institute, School of Medicine, Stanford University, Stanford, CA
| | - Mary Beth Terry
- Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY; Herbert Irving Comprehensive Cancer Center, Columbia University, New York, NY
| | - John L Hopper
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Victoria, Australia
| | - Melissa C Southey
- Precision Medicine, School of Clinical Sciences at Monash Health, Monash University, Clayton, Victoria, Australia; Department of Clinical Pathology, Melbourne Medical School, University of Melbourne, Melbourne, Victoria, Australia; Cancer Epidemiology Division, Cancer Council Victoria, Melbourne, Victoria, Australia
| | - Irene L Andrulis
- Fred A. Litwin Center for Cancer Genetics, Lunenfeld-Tanenbaum Research Institute of Mount Sinai Hospital, Toronto, Ontario, Canada; Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Marc Tischkowitz
- Department of Medical Genetics, NIHR Cambridge Biomedical Research Centre, Cambridge University Hospitals NHS Foundation Trust, University of Cambridge, Cambridge, United Kingdom
| | - Ramunas Janavicius
- Department of Human and Medical Genetics, Institute of Biomedical Sciences, Faculty of Medicine, Vilnius University, Vilnius, Lithuania; State Research Institute Centre for Innovative Medicine, Vilnius, Lithuania
| | - Susanne E Boonen
- Department of Clinical Genetics, Odense University Hospital, Odense, Denmark
| | - Lone Kroeldrup
- Department of Clinical Genetics, Odense University Hospital, Odense, Denmark
| | - Liliana Varesco
- Unit of Hereditary Cancer, IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Ute Hamann
- Molecular Genetics of Breast Cancer, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Ana Vega
- Fundación Pública galega Medicina Xenómica-SERGAS, Grupo de Medicina Xenómica-USC, CIBERER, IDIS, Santiago de Compostela, Spain
| | - Edenir I Palmero
- Molecular Oncology Research Center, Barretos Cancer Hospital, São Paulo, Brazil; National Cancer Institute, Rio de Janeiro, Brazil
| | - Judy Garber
- Center for Cancer Genetics and Prevention, Dana-Farber Cancer Institute, Boston, MA
| | - Marco Montagna
- Immunology and Molecular Oncology Unit, IOV - Istituto Oncologico Veneto - IRCCS, Padova, Italy
| | - Christi J Van Asperen
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Lenka Foretova
- Department of Cancer Epidemiology and Genetics, Masaryk Memorial Cancer Institute, Brno, Czech Republic
| | - Mark H Greene
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD
| | - Tina Selkirk
- NorthShore University HealthSystem, University of Chicago, Evanston, IL
| | - Pal Moller
- Department of Tumor Biology, Institute of Cancer Research, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway; Center for Hereditary Tumors, HELIOS-Klinikum Wuppertal, University of Witten-Herdecke, Wuppertal, Germany
| | - Amanda E Toland
- Department of Cancer Biology and Genetics, College of Medicine, The Ohio State University, Columbus, OH
| | - Susan M Domchek
- Basser Center for BRCA, Abramson Cancer Center, Penn Medicine, University of Pennsylvania, Philadelphia, PA
| | - Paul A James
- Parkville Familial Cancer Centre, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia; The Sir Peter MacCallum Department of Oncology, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne, Victoria, Australia
| | - Heather Thorne
- The Sir Peter MacCallum Department of Oncology, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne, Victoria, Australia
| | - Diana M Eccles
- Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Sarah M Nielsen
- Center for Clinical Cancer Genetics, The University of Chicago, Chicago, IL
| | - Siranoush Manoukian
- Unit of Medical Genetics, Department of Medical Oncology and Hematology, Fondazione IRCCS Istituto Nazionale dei Tumori, Milano, Italy
| | - Barbara Pasini
- Medical Genetics Unit, Department of Medical Sciences, University of Torino, Torino, Italy
| | - Maria A Caligo
- SOD Genetica Molecolare, University Hospital, Pisa, Italy
| | - Conxi Lazaro
- ONCOBELL-IDIBELL-IDIBGI-IGTP, CIBERONC, Hereditary Cancer Program, Catalan Institute of Oncology, Barcelona, Spain
| | - Judy Kirk
- Familial Cancer Service, Crown Princess Mary Cancer Centre, Westmead Hospital, Sydney Medical School, University of Sydney, Centre for Cancer Research, The Westmead Institute for Medical Research, Westmead, New South Wales, Australia
| | - Barbara Wappenschmidt
- Center for Hereditary Breast and Ovarian Cancer, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany; Center for Integrated Oncology (CIO), Faculty of Medicine, University of Cologne, Cologne, Germany
| | - Amanda B Spurdle
- Department of Genetics and Computational Biology, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - Fergus J Couch
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN
| | - Rita Schmutzler
- Center for Hereditary Breast and Ovarian Cancer, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany; Center for Integrated Oncology (CIO), Faculty of Medicine, University of Cologne, Cologne, Germany
| | - David E Goldgar
- Cancer Control and Population Science, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT; Department of Dermatology, University of Utah School of Medicine, Salt Lake City, UT.
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Yin J, Zhou J, Chen J, Xu T, Zhang Z, Zhang H, Yuan C, Cheng X, Qin Y, Zheng B, Wang C, Yang S, Jia Z. Case Report: A Novel Variant c.2262+3A>T of the SCN5A Gene Results in Intron Retention Associated With Incessant Ventricular Tachycardias. Front Med (Lausanne) 2021; 8:659119. [PMID: 34422849 PMCID: PMC8371685 DOI: 10.3389/fmed.2021.659119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 06/30/2021] [Indexed: 11/18/2022] Open
Abstract
Objective: Voltage-gated sodium channel Nav1.5 encoded by the SCN5A gene plays crucial roles in cardiac electrophysiology. Previous genetic studies have shown that mutations in SCN5A are associated with multiple inherited cardiac arrhythmias. Here, we investigated the molecular defect in a Chinese boy with clinical manifestations of arrhythmias. Methods: Gene variations were screened using whole-exome sequencing and validated by direct Sanger sequencing. A minigene assay and reverse transcription PCR (RT-PCR) were performed to confirm the effects of splice variants in vitro. Western blot analysis was carried out to determine whether the c.2262+3A>T variant produced a truncated protein. Results: By genetic analysis, we identified a novel splice variant c.2262+3A>T in SCN5A gene in a Chinese boy with incessant ventricular tachycardias (VT). This variant was predicted to activate a new cryptic splice donor site and was identified by in silico analysis. The variant retained 79 bp at the 5′ end of intron 14 in the mature mRNA. Furthermore, the mutant transcript that created a premature stop codon at 818 amino acids [p.(R818*)] could be produced as a truncated protein. Conclusion: We verified the pathogenic effect of splicing variant c.2262+3A>T, which disturbed the normal mRNA splicing and caused a truncated protein, suggesting that splice variants play an important role in the molecular basis of early onset incessant ventricular tachycardias, and careful molecular profiling of these patients will be essential for future effective personalized treatment options.
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Affiliation(s)
- Jie Yin
- Department of Cardiology, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Jia Zhou
- Department of Cardiology, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Jinlong Chen
- Department of Cardiology, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Ting Xu
- Department of Cardiology, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Zhongman Zhang
- Department of Cardiology, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Han Zhang
- Department of Cardiology, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Chang Yuan
- Department of Cardiology, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Xueying Cheng
- Department of Cardiology, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Yuming Qin
- Department of Cardiology, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Bixia Zheng
- Nanjing Key Laboratory of Pediatrics, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Chunli Wang
- Nanjing Key Laboratory of Pediatrics, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Shiwei Yang
- Department of Cardiology, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Zhanjun Jia
- Nanjing Key Laboratory of Pediatrics, Children's Hospital of Nanjing Medical University, Nanjing, China
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15
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Bueno-Martínez E, Sanoguera-Miralles L, Valenzuela-Palomo A, Lorca V, Gómez-Sanz A, Carvalho S, Allen J, Infante M, Pérez-Segura P, Lázaro C, Easton DF, Devilee P, Vreeswijk MPG, de la Hoya M, Velasco EA. RAD51D Aberrant Splicing in Breast Cancer: Identification of Splicing Regulatory Elements and Minigene-Based Evaluation of 53 DNA Variants. Cancers (Basel) 2021; 13:2845. [PMID: 34200360 PMCID: PMC8201001 DOI: 10.3390/cancers13112845] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 06/01/2021] [Accepted: 06/03/2021] [Indexed: 12/18/2022] Open
Abstract
RAD51D loss-of-function variants increase lifetime risk of breast and ovarian cancer. Splicing disruption is a frequent pathogenic mechanism associated with variants in susceptibility genes. Herein, we have assessed the splicing and clinical impact of splice-site and exonic splicing enhancer (ESE) variants identified through the study of ~113,000 women of the BRIDGES cohort. A RAD51D minigene with exons 2-9 was constructed in splicing vector pSAD. Eleven BRIDGES splice-site variants (selected by MaxEntScan) were introduced into the minigene by site-directed mutagenesis and tested in MCF-7 cells. The 11 variants disrupted splicing, collectively generating 25 different aberrant transcripts. All variants but one produced negligible levels (<3.4%) of the full-length (FL) transcript. In addition, ESE elements of the alternative exon 3 were mapped by testing four overlapping exonic microdeletions (≥30-bp), revealing an ESE-rich interval (c.202_235del) with critical sequences for exon 3 recognition that might have been affected by germline variants. Next, 26 BRIDGES variants and 16 artificial exon 3 single-nucleotide substitutions were also assayed. Thirty variants impaired splicing with variable amounts (0-65.1%) of the FL transcript, although only c.202G>A demonstrated a complete aberrant splicing pattern without the FL transcript. On the other hand, c.214T>C increased efficiency of exon 3 recognition, so only the FL transcript was detected (100%). In conclusion, 41 RAD51D spliceogenic variants (28 of which were from the BRIDGES cohort) were identified by minigene assays. We show that minigene-based mapping of ESEs is a powerful approach for identifying ESE hotspots and ESE-disrupting variants. Finally, we have classified nine variants as likely pathogenic according to ACMG/AMP-based guidelines, highlighting the complex relationship between splicing alterations and variant interpretation.
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Affiliation(s)
- Elena Bueno-Martínez
- Splicing and Genetic Susceptibility to Cancer Laboratory, Unidad de Excelencia Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC-UVa), 47003 Valladolid, Spain; (E.B.-M.); (L.S.-M.); (A.V.-P.)
| | - Lara Sanoguera-Miralles
- Splicing and Genetic Susceptibility to Cancer Laboratory, Unidad de Excelencia Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC-UVa), 47003 Valladolid, Spain; (E.B.-M.); (L.S.-M.); (A.V.-P.)
| | - Alberto Valenzuela-Palomo
- Splicing and Genetic Susceptibility to Cancer Laboratory, Unidad de Excelencia Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC-UVa), 47003 Valladolid, Spain; (E.B.-M.); (L.S.-M.); (A.V.-P.)
| | - Víctor Lorca
- Molecular Oncology Laboratory CIBERONC, IdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos), Hospital Clinico San Carlos, 28040 Madrid, Spain; (V.L.); (A.G.-S.); (P.P.-S.)
| | - Alicia Gómez-Sanz
- Molecular Oncology Laboratory CIBERONC, IdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos), Hospital Clinico San Carlos, 28040 Madrid, Spain; (V.L.); (A.G.-S.); (P.P.-S.)
| | - Sara Carvalho
- Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary Care, University of Cambridge, Cambridge CB1 8RN, UK; (S.C.); (J.A.); (D.F.E.)
| | - Jamie Allen
- Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary Care, University of Cambridge, Cambridge CB1 8RN, UK; (S.C.); (J.A.); (D.F.E.)
| | - Mar Infante
- Cancer Genetics, Unidad de Excelencia Instituto de Biología y Genética Molecular (CSIC-UVa), 47003 Valladolid, Spain;
| | - Pedro Pérez-Segura
- Molecular Oncology Laboratory CIBERONC, IdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos), Hospital Clinico San Carlos, 28040 Madrid, Spain; (V.L.); (A.G.-S.); (P.P.-S.)
| | - Conxi Lázaro
- Hereditary Cancer Program, Catalan Institute of Oncology, IDIBELL and CIBERONC, 08908 Hospitalet de Llobregat, Spain;
| | - Douglas F. Easton
- Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary Care, University of Cambridge, Cambridge CB1 8RN, UK; (S.C.); (J.A.); (D.F.E.)
| | - Peter Devilee
- Department of Human Genetics, Leiden University Medical Center, 2300RC Leiden, The Netherlands; (P.D.); (M.P.G.V.)
| | - Maaike P. G. Vreeswijk
- Department of Human Genetics, Leiden University Medical Center, 2300RC Leiden, The Netherlands; (P.D.); (M.P.G.V.)
| | - Miguel de la Hoya
- Molecular Oncology Laboratory CIBERONC, IdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos), Hospital Clinico San Carlos, 28040 Madrid, Spain; (V.L.); (A.G.-S.); (P.P.-S.)
| | - Eladio A. Velasco
- Splicing and Genetic Susceptibility to Cancer Laboratory, Unidad de Excelencia Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC-UVa), 47003 Valladolid, Spain; (E.B.-M.); (L.S.-M.); (A.V.-P.)
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16
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Di Scipio M, Tavares E, Deshmukh S, Audo I, Green-Sanderson K, Zubak Y, Zine-Eddine F, Pearson A, Vig A, Tang CY, Mollica A, Karas J, Tumber A, Yu CW, Billingsley G, Wilson MD, Zeitz C, Héon E, Vincent A. Phenotype Driven Analysis of Whole Genome Sequencing Identifies Deep Intronic Variants that Cause Retinal Dystrophies by Aberrant Exonization. Invest Ophthalmol Vis Sci 2021; 61:36. [PMID: 32881472 PMCID: PMC7443117 DOI: 10.1167/iovs.61.10.36] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Purpose To demonstrate the effectiveness of combining retinal phenotyping and focused variant filtering from genome sequencing (GS) in identifying deep intronic disease causing variants in inherited retinal dystrophies. Methods Affected members from three pedigrees with classical enhanced S-cone syndrome (ESCS; Pedigree 1), congenital stationary night blindness (CSNB; Pedigree 2), and achromatopsia (ACHM; Pedigree 3), respectively, underwent detailed ophthalmologic evaluation, optical coherence tomography, and electroretinography. The probands underwent panel-based genetic testing followed by GS analysis. Minigene constructs (NR2E3, GPR179 and CNGB3) and patient-derived cDNA experiments (NR2E3 and GPR179) were performed to assess the functional effect of the deep intronic variants. Results The electrophysiological findings confirmed the clinical diagnosis of ESCS, CSNB, and ACHM in the respective pedigrees. Panel-based testing revealed heterozygous pathogenic variants in NR2E3 (NM_014249.3; c.119-2A>C; Pedigree 1) and CNGB3 (NM_019098.4; c.1148delC/p.Thr383Ilefs*13; Pedigree 3). The GS revealed heterozygous deep intronic variants in Pedigrees 1 (NR2E3; c.1100+1124G>A) and 3 (CNGB3; c.852+4751A>T), and a homozygous GPR179 variant in Pedigree 2 (NM_001004334.3; c.903+343G>A). The identified variants segregated with the phenotype in all pedigrees. All deep intronic variants were predicted to generate a splice acceptor gain causing aberrant exonization in NR2E3 [89 base pairs (bp)], GPR179 (197 bp), and CNGB3 (73 bp); splicing defects were validated through patient-derived cDNA experiments and/or minigene constructs and rescued by antisense oligonucleotide treatment. Conclusions Deep intronic mutations contribute to missing heritability in retinal dystrophies. Combining results from phenotype-directed gene panel testing, GS, and in silico splice prediction tools can help identify these difficult-to-detect pathogenic deep intronic variants.
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Affiliation(s)
- Matteo Di Scipio
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Erika Tavares
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Shriya Deshmukh
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Isabelle Audo
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France.,CHNO des Quinze-Vingts, INSERM-DGOS CIC1423, Paris, France.,University College London Institute of Ophthalmology, London, United Kingdom
| | - Kit Green-Sanderson
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Yuliya Zubak
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Fayçal Zine-Eddine
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Alexander Pearson
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Anjali Vig
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Chen Yu Tang
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Antonio Mollica
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Jonathan Karas
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Anupreet Tumber
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, Canada
| | - Caberry W Yu
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Gail Billingsley
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Michael D Wilson
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Christina Zeitz
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Elise Héon
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada.,Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, Canada.,Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Canada
| | - Ajoy Vincent
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada.,Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, Canada.,Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Canada
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17
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Sanoguera-Miralles L, Valenzuela-Palomo A, Bueno-Martínez E, Llovet P, Díez-Gómez B, Caloca MJ, Pérez-Segura P, Fraile-Bethencourt E, Colmena M, Carvalho S, Allen J, Easton DF, Devilee P, Vreeswijk MPG, de la Hoya M, Velasco EA. Comprehensive Functional Characterization and Clinical Interpretation of 20 Splice-Site Variants of the RAD51C Gene. Cancers (Basel) 2020; 12:E3771. [PMID: 33333735 PMCID: PMC7765170 DOI: 10.3390/cancers12123771] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 12/08/2020] [Accepted: 12/09/2020] [Indexed: 12/12/2022] Open
Abstract
Hereditary breast and/or ovarian cancer is a highly heterogeneous disease with more than 10 known disease-associated genes. In the framework of the BRIDGES project (Breast Cancer Risk after Diagnostic Gene Sequencing), the RAD51C gene has been sequenced in 60,466 breast cancer patients and 53,461 controls. We aimed at functionally characterizing all the identified genetic variants that are predicted to disrupt the splicing process. Forty RAD51C variants of the intron-exon boundaries were bioinformatically analyzed, 20 of which were selected for splicing functional assays. To test them, a splicing reporter minigene with exons 2 to 8 was designed and constructed. This minigene generated a full-length transcript of the expected size (1062 nucleotides), sequence, and structure (Vector exon V1- RAD51C exons_2-8- Vector exon V2). The 20 candidate variants were genetically engineered into the wild type minigene and functionally assayed in MCF-7 cells. Nineteen variants (95%) impaired splicing, while 18 of them produced severe splicing anomalies. At least 35 transcripts were generated by the mutant minigenes: 16 protein-truncating, 6 in-frame, and 13 minor uncharacterized isoforms. According to ACMG/AMP-based standards, 15 variants could be classified as pathogenic or likely pathogenic variants: c.404G > A, c.405-6T > A, c.571 + 4A > G, c.571 + 5G > A, c.572-1G > T, c.705G > T, c.706-2A > C, c.706-2A > G, c.837 + 2T > C, c.905-3C > G, c.905-2A > C, c.905-2_905-1del, c.965 + 5G > A, c.1026 + 5_1026 + 7del, and c.1026 + 5G > T.
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Affiliation(s)
- Lara Sanoguera-Miralles
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC-UVa), 47003 Valladolid, Spain; (L.S.-M.); (A.V.-P.); (E.B.-M.); (B.D.-G.); (E.F.-B.)
| | - Alberto Valenzuela-Palomo
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC-UVa), 47003 Valladolid, Spain; (L.S.-M.); (A.V.-P.); (E.B.-M.); (B.D.-G.); (E.F.-B.)
| | - Elena Bueno-Martínez
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC-UVa), 47003 Valladolid, Spain; (L.S.-M.); (A.V.-P.); (E.B.-M.); (B.D.-G.); (E.F.-B.)
| | - Patricia Llovet
- Molecular Oncology Laboratory CIBERONC, Hospital Clinico San Carlos, IdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos), 28040 Madrid, Spain; (P.L.); (P.P.-S.); (M.C.)
| | - Beatriz Díez-Gómez
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC-UVa), 47003 Valladolid, Spain; (L.S.-M.); (A.V.-P.); (E.B.-M.); (B.D.-G.); (E.F.-B.)
| | - María José Caloca
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC-UVa), 47003 Valladolid, Spain;
| | - Pedro Pérez-Segura
- Molecular Oncology Laboratory CIBERONC, Hospital Clinico San Carlos, IdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos), 28040 Madrid, Spain; (P.L.); (P.P.-S.); (M.C.)
| | - Eugenia Fraile-Bethencourt
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC-UVa), 47003 Valladolid, Spain; (L.S.-M.); (A.V.-P.); (E.B.-M.); (B.D.-G.); (E.F.-B.)
- Knight Cancer Research Building, 2720 S Moody Ave, Portland, OR 97201, USA
| | - Marta Colmena
- Molecular Oncology Laboratory CIBERONC, Hospital Clinico San Carlos, IdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos), 28040 Madrid, Spain; (P.L.); (P.P.-S.); (M.C.)
| | - Sara Carvalho
- Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary Care, University of Cambridge, Cambridge CB1 8RN, UK; (S.C.); (J.A.); (D.F.E.)
| | - Jamie Allen
- Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary Care, University of Cambridge, Cambridge CB1 8RN, UK; (S.C.); (J.A.); (D.F.E.)
| | - Douglas F. Easton
- Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary Care, University of Cambridge, Cambridge CB1 8RN, UK; (S.C.); (J.A.); (D.F.E.)
| | - Peter Devilee
- Leiden University Medical Center, Department of Human Genetics, 2300RC Leiden, The Netherlands; (P.D.); (M.P.G.V.)
| | - Maaike P. G. Vreeswijk
- Leiden University Medical Center, Department of Human Genetics, 2300RC Leiden, The Netherlands; (P.D.); (M.P.G.V.)
| | - Miguel de la Hoya
- Molecular Oncology Laboratory CIBERONC, Hospital Clinico San Carlos, IdISSC (Instituto de Investigación Sanitaria del Hospital Clínico San Carlos), 28040 Madrid, Spain; (P.L.); (P.P.-S.); (M.C.)
| | - Eladio A. Velasco
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC-UVa), 47003 Valladolid, Spain; (L.S.-M.); (A.V.-P.); (E.B.-M.); (B.D.-G.); (E.F.-B.)
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18
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Canson D, Glubb D, Spurdle AB. Variant effect on splicing regulatory elements, branchpoint usage, and pseudoexonization: Strategies to enhance bioinformatic prediction using hereditary cancer genes as exemplars. Hum Mutat 2020; 41:1705-1721. [PMID: 32623769 DOI: 10.1002/humu.24074] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Revised: 06/26/2020] [Accepted: 07/02/2020] [Indexed: 12/15/2022]
Abstract
It is possible to estimate the prior probability of pathogenicity for germline disease gene variants based on bioinformatic prediction of variant effect/s. However, routinely used approaches have likely led to the underestimation and underreporting of variants located outside donor and acceptor splice site motifs that affect messenger RNA (mRNA) processing. This review presents information about hereditary cancer gene germline variants, outside native splice sites, with experimentally validated splicing effects. We list 95 exonic variants that impact splicing regulatory elements (SREs) in BRCA1, BRCA2, MLH1, MSH2, MSH6, and PMS2. We utilized a pre-existing large-scale BRCA1 functional data set to map functional SREs, and assess the relative performance of different tools to predict effects of 283 variants on such elements. We also describe rare examples of intronic variants that impact branchpoint (BP) sites and create pseudoexons. We discuss the challenges in predicting variant effect on BP site usage and pseudoexonization, and suggest strategies to improve the bioinformatic prioritization of such variants for experimental validation. Importantly, our review and analysis highlights the value of considering impact of variants outside donor and acceptor motifs on mRNA splicing and disease causation.
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Affiliation(s)
- Daffodil Canson
- Genetics and Computational Biology Department, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
- Faculty of Medicine, The University of Queensland, Brisbane, Queensland, Australia
| | - Dylan Glubb
- Genetics and Computational Biology Department, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - Amanda B Spurdle
- Genetics and Computational Biology Department, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
- Faculty of Medicine, The University of Queensland, Brisbane, Queensland, Australia
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19
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Gailite L, Valenzuela-Palomo A, Sanoguera-Miralles L, Rots D, Kreile M, Velasco EA. UGT1A1 Variants c.864+5G>T and c.996+2_996+5del of a Crigler-Najjar Patient Induce Aberrant Splicing in Minigene Assays. Front Genet 2020; 11:169. [PMID: 32211025 PMCID: PMC7067894 DOI: 10.3389/fgene.2020.00169] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 02/12/2020] [Indexed: 11/13/2022] Open
Abstract
A large fraction of DNA variants impairs pre-mRNA splicing in human hereditary disorders. Crigler-Najjar syndrome (CNS) is characterized by a severe unconjugated hyperbilirubinemia caused by variants in the UGT1A1 gene. We previously reported one CNS-type II patient with two splice-site variants in trans (c.864+5G>T and c.996+2_996+5del). According to MaxEntScan, both disrupt their corresponding donor sites (c.864+5G>T: 6.99 → 2.28; c.996+2_996+5del: 5.96 → -11.02), so they were selected for subsequent functional tests. Given the unavailability of patient RNA, we constructed an UGT1A1 splicing-reporter minigene with exons 1-4 to characterize the underlying splicing anomaly. The variant c.996+2_996+5del generated two aberrant transcripts, Δ(E2) (exon 2 skipping/64%) and ▼(E2q135) (intron retention of 135-nt/36%), which lead to the loss of 18 conserved amino-acids and the gain of 45 new ones of a critical functional domain, respectively. The c.864+5G>T variant mainly produced the aberrant transcript Δ(E1q141) (141-nt deletion/70.4%) and the full-length isoform (29.6%). Δ(E1q141) would provoke the loss of 47 amino-acids of the N-terminal domain that encodes for substrate specificity. Thus, the three anomalous transcripts are likely to inactivate UGT1A1. Moreover, this patient is also homozygous for the promoter variant A(TA)7TAA that decreases UGT1A1 expression by 70%, so the full-length transcript produced by c.864+5G>T would be even more reduced (<9%), thus supporting the diagnosis of CNS-type II. Therefore, minigenes represent valuable tools for the functional and clinical classifications of genetic variants.
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Affiliation(s)
- Linda Gailite
- Scientific Laboratory of Molecular Genetics, Riga Stradins University, Riga, Latvia
| | - Alberto Valenzuela-Palomo
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular (CSIC-UVa), Valladolid, Spain
| | - Lara Sanoguera-Miralles
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular (CSIC-UVa), Valladolid, Spain
| | - Dmitrijs Rots
- Scientific Laboratory of Molecular Genetics, Riga Stradins University, Riga, Latvia
| | - Madara Kreile
- Scientific Laboratory of Molecular Genetics, Riga Stradins University, Riga, Latvia
| | - Eladio A Velasco
- Splicing and Genetic Susceptibility to Cancer, Instituto de Biología y Genética Molecular (CSIC-UVa), Valladolid, Spain
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Li L, Cao Y, Zhao F, Mao B, Ren X, Wang Y, Guan Y, You Y, Li S, Yang T, Zhao X. Validation and Classification of Atypical Splicing Variants Associated With Osteogenesis Imperfecta. Front Genet 2019; 10:979. [PMID: 31737030 PMCID: PMC6832110 DOI: 10.3389/fgene.2019.00979] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 09/13/2019] [Indexed: 01/17/2023] Open
Abstract
Osteogenesis Imperfecta (OI) is a rare inherited bone dysplasia, which is mainly caused by mutations in genes encoding type I collagen including COL1A1 and COL1A2. It has been well established to identify the classical variants as well as consensus splicing-site-variants in these genes in our previous studies. However, how atypical variants affect splicing in OI patients remains unclear. From a cohort of 867 OI patients, we collected blood samples from 34 probands which contain 29 variants that are located close to splice donor/acceptor sites in either COL1A1 or COL1A2. By conducting minigene assay and sequencing analysis, we found that 17 out of 29 variants led to aberrant splicing effects, while no remarkable aberrant splicing effect was observed in the remaining 12 variants. Among the 17 variants that affect splicing, 14 variants led to single splicing influence: 9 led to exon skipping, 2 resulted in truncated exon, and 3 caused intron retention. There were three complicated cases showing more than one mutant transcript caused by recognition of several different splice sites. This functional study expands our knowledge of atypical splicing variants, and emphasizes the importance of clarifying the splicing effect for variants near exon/intron boundaries in OI.
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Affiliation(s)
- Lulu Li
- Department of Medical Genetics, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & School of Basic Medicine, Peking Union Medical College, Beijing, China
| | - Yixuan Cao
- Department of Medical Genetics, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & School of Basic Medicine, Peking Union Medical College, Beijing, China
| | - Feiyue Zhao
- Department of Medical Genetics, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & School of Basic Medicine, Peking Union Medical College, Beijing, China
| | - Bin Mao
- Department of Medical Genetics, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & School of Basic Medicine, Peking Union Medical College, Beijing, China
| | - Xiuzhi Ren
- Department of Orthopaedics, The People's Hospital of Wuqing District, Tianjin, China
| | - Yanzhou Wang
- Department of Pediatric Orthopaedics, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China
| | - Yun Guan
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD, United States
| | - Yi You
- Department of Medical Genetics, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & School of Basic Medicine, Peking Union Medical College, Beijing, China
| | - Shan Li
- Department of Medical Genetics, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & School of Basic Medicine, Peking Union Medical College, Beijing, China
| | - Tao Yang
- Department of Medical Genetics, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & School of Basic Medicine, Peking Union Medical College, Beijing, China
| | - Xiuli Zhao
- Department of Medical Genetics, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & School of Basic Medicine, Peking Union Medical College, Beijing, China
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