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Schmidt J, Dreha-Kulaczewski S, Zafeiriou MP, Schreiber MK, Wilken B, Funke R, Neuhofer CM, Altmüller J, Thiele H, Nürnberg P, Biskup S, Li Y, Zimmermann WH, Kaulfuß S, Yigit G, Wollnik B. Somatic mosaicism in STAG2-associated cohesinopathies: Expansion of the genotypic and phenotypic spectrum. Front Cell Dev Biol 2022; 10:1025332. [PMID: 36467423 PMCID: PMC9710855 DOI: 10.3389/fcell.2022.1025332] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 10/26/2022] [Indexed: 08/25/2024] Open
Abstract
STAG2 is a component of the large, evolutionarily highly conserved cohesin complex, which has been linked to various cellular processes like genome organization, DNA replication, gene expression, heterochromatin formation, sister chromatid cohesion, and DNA repair. A wide spectrum of germline variants in genes encoding subunits or regulators of the cohesin complex have previously been identified to cause distinct but phenotypically overlapping multisystem developmental disorders belonging to the group of cohesinopathies. Pathogenic variants in STAG2 have rarely been implicated in an X-linked cohesinopathy associated with undergrowth, developmental delay, and dysmorphic features. Here, we describe for the first time a mosaic STAG2 variant in an individual with developmental delay, microcephaly, and hemihypotrophy of the right side. We characterized the grade of mosaicism by deep sequencing analysis on DNA extracted from EDTA blood, urine and buccal swabs. Furthermore, we report an additional female with a novel de novo splice variant in STAG2. Interestingly, both individuals show supernumerary nipples, a feature that has not been reported associated to STAG2 before. Remarkably, additional analysis of STAG2 transcripts in both individuals showed only wildtype transcripts, even after blockage of nonsense-mediated decay using puromycin in blood lymphocytes. As the phenotype of STAG2-associated cohesinopathies is dominated by global developmental delay, severe microcephaly, and brain abnormalities, we investigated the expression of STAG2 and other related components of the cohesin complex during Bioengineered Neuronal Organoids (BENOs) generation by RNA sequencing. Interestingly, we observed a prominent expression of STAG2, especially between culture days 0 and 15, indicating an essential function of STAG2 in early brain development. In summary, we expand the genotypic and phenotypic spectrum of STAG2-associated cohesinopathies and show that BENOs represent a promising model to gain further insights into the critical role of STAG2 in the complex process of nervous system development.
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Affiliation(s)
- Julia Schmidt
- Institute of Human Genetics, University Medical Center Göttingen, Göttingen, Germany
| | - Steffi Dreha-Kulaczewski
- Department of Pediatics and Adolescent Medicine, University Medical Center Göttingen, Göttingen, Germany
| | - Maria-Patapia Zafeiriou
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Göttingen, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
- Cluster of Excellence “Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells” (MBExC), University of Göttingen, Göttingen, Germany
| | - Marie-Kristin Schreiber
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Göttingen, Germany
- Cluster of Excellence “Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells” (MBExC), University of Göttingen, Göttingen, Germany
| | - Bernd Wilken
- Department of Pediatric Neurology, Klinikum Kassel, Kassel, Germany
| | - Rudolf Funke
- Department of Pediatric Neurology, Klinikum Kassel, Kassel, Germany
| | - Christiane M Neuhofer
- Institute of Human Genetics, University Medical Center Göttingen, Göttingen, Germany
- Institute of Neurogenomics, Helmholtz Zentrum Munich, Munich, Germany
- Department of Neurology, Friedrich-Baur-Institute, LMU Hospital, Ludwig Maximilians University, Munich, Germany
| | - Janine Altmüller
- Cologne Center for Genomics (CCG), University of Cologne, Faculty of Medicine, University Hospital Cologne, Cologne, Germany
- Berlin Institute of Health at Charité, Core Facility Genomics, Berlin, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Holger Thiele
- Cologne Center for Genomics (CCG), University of Cologne, Faculty of Medicine, University Hospital Cologne, Cologne, Germany
| | - Peter Nürnberg
- Cologne Center for Genomics (CCG), University of Cologne, Faculty of Medicine, University Hospital Cologne, Cologne, Germany
| | - Saskia Biskup
- CeGaT GmbH, Center for Genomics and Transcriptomics, Tübingen, Germany
| | - Yun Li
- Institute of Human Genetics, University Medical Center Göttingen, Göttingen, Germany
| | - Wolfram Hubertus Zimmermann
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Göttingen, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
- Cluster of Excellence “Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells” (MBExC), University of Göttingen, Göttingen, Germany
| | - Silke Kaulfuß
- Institute of Human Genetics, University Medical Center Göttingen, Göttingen, Germany
| | - Gökhan Yigit
- Institute of Human Genetics, University Medical Center Göttingen, Göttingen, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
| | - Bernd Wollnik
- Institute of Human Genetics, University Medical Center Göttingen, Göttingen, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
- Cluster of Excellence “Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells” (MBExC), University of Göttingen, Göttingen, Germany
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Gil-Salvador M, Latorre-Pellicer A, Lucia-Campos C, Arnedo M, Darnaude MT, Díaz de Bustamante A, Villares R, Palma Milla C, Puisac B, Musio A, Ramos FJ, Pié J. Case report: A novel case of parental mosaicism in SMC1A gene causes inherited Cornelia de Lange syndrome. Front Genet 2022; 13:993064. [PMID: 36246631 PMCID: PMC9554350 DOI: 10.3389/fgene.2022.993064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 09/05/2022] [Indexed: 11/18/2022] Open
Abstract
Ultimate advances in genetic technologies have permitted the detection of transmitted cases of congenital diseases due to parental gonadosomatic mosaicism. Regarding Cornelia de Lange syndrome (CdLS), up to date, only a few cases are known to follow this inheritance pattern. However, the high prevalence of somatic mosaicism recently reported in this syndrome (∼13%), together with the disparity observed in tissue distribution of the causal variant, suggests that its prevalence in this disorder could be underestimated. Here, we report a new case of parental gonadosomatic mosaicism in SMC1A gene that causes inherited CdLS, in which the mother of the patient carries the causative variant in very low allele frequencies in buccal swab and blood. While the affected child presents with typical CdLS phenotype, his mother does not show any clinical manifestations. As regards SMC1A, the difficulty of clinical identification of carrier females has been already recognized, as well as the gender differences observed in CdLS expressivity when the causal variant is found in this gene. Currently, the use of DNA deep-sequencing techniques is highly recommended when it comes to molecular diagnosis of patients, as well as in co-segregation studies. These enable us to uncover gonadosomatic mosaic events in asymptomatic or oligosymptomatic parents that had been overlooked so far, which might have great implications regarding genetic counseling for recurrence risk.
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Affiliation(s)
- Marta Gil-Salvador
- Unit of Clinical Genetics and Functional Genomics, Department of Pharmacology and Physiology, School of Medicine, CIBERER and IIS-Aragon, University of Zaragoza, Zaragoza, Spain
| | - Ana Latorre-Pellicer
- Unit of Clinical Genetics and Functional Genomics, Department of Pharmacology and Physiology, School of Medicine, CIBERER and IIS-Aragon, University of Zaragoza, Zaragoza, Spain
| | - Cristina Lucia-Campos
- Unit of Clinical Genetics and Functional Genomics, Department of Pharmacology and Physiology, School of Medicine, CIBERER and IIS-Aragon, University of Zaragoza, Zaragoza, Spain
| | - María Arnedo
- Unit of Clinical Genetics and Functional Genomics, Department of Pharmacology and Physiology, School of Medicine, CIBERER and IIS-Aragon, University of Zaragoza, Zaragoza, Spain
| | | | | | - Rebeca Villares
- Neuropediatrics, University Hospital of Móstoles, Madrid, Spain
| | | | - Beatriz Puisac
- Unit of Clinical Genetics and Functional Genomics, Department of Pharmacology and Physiology, School of Medicine, CIBERER and IIS-Aragon, University of Zaragoza, Zaragoza, Spain
| | - Antonio Musio
- Institute for Biomedical Technologies (ITB), National Research Council (CNR), Pisa, Italy
| | - Feliciano J. Ramos
- Unit of Clinical Genetics, Service of Paediatrics, Department of Paediatrics, University Hospital “Lozano Blesa”, School of Medicine, CIBERER and IIS-Aragon, University of Zaragoza, Zaragoza, Spain
| | - Juan Pié
- Unit of Clinical Genetics and Functional Genomics, Department of Pharmacology and Physiology, School of Medicine, CIBERER and IIS-Aragon, University of Zaragoza, Zaragoza, Spain
- *Correspondence: Juan Pié,
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Methods to Improve Molecular Diagnosis in Genomic Cold Cases in Pediatric Neurology. Genes (Basel) 2022; 13:genes13020333. [PMID: 35205378 PMCID: PMC8871714 DOI: 10.3390/genes13020333] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 02/06/2022] [Accepted: 02/07/2022] [Indexed: 02/04/2023] Open
Abstract
During the last decade, genetic testing has emerged as an important etiological diagnostic tool for Mendelian diseases, including pediatric neurological conditions. A genetic diagnosis has a considerable impact on disease management and treatment; however, many cases remain undiagnosed after applying standard diagnostic sequencing techniques. This review discusses various methods to improve the molecular diagnostic rates in these genomic cold cases. We discuss extended analysis methods to consider, non-Mendelian inheritance models, mosaicism, dual/multiple diagnoses, periodic re-analysis, artificial intelligence tools, and deep phenotyping, in addition to integrating various omics methods to improve variant prioritization. Last, novel genomic technologies, including long-read sequencing, artificial long-read sequencing, and optical genome mapping are discussed. In conclusion, a more comprehensive molecular analysis and a timely re-analysis of unsolved cases are imperative to improve diagnostic rates. In addition, our current understanding of the human genome is still limited due to restrictions in technologies. Novel technologies are now available that improve upon some of these limitations and can capture all human genomic variation more accurately. Last, we recommend a more routine implementation of high molecular weight DNA extraction methods that is coherent with the ability to use and/or optimally benefit from these novel genomic methods.
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Latorre-Pellicer A, Gil-Salvador M, Parenti I, Lucia-Campos C, Trujillano L, Marcos-Alcalde I, Arnedo M, Ascaso Á, Ayerza-Casas A, Antoñanzas-Pérez R, Gervasini C, Piccione M, Mariani M, Weber A, Kanber D, Kuechler A, Munteanu M, Khuller K, Bueno-Lozano G, Puisac B, Gómez-Puertas P, Selicorni A, Kaiser FJ, Ramos FJ, Pié J. Clinical relevance of postzygotic mosaicism in Cornelia de Lange syndrome and purifying selection of NIPBL variants in blood. Sci Rep 2021; 11:15459. [PMID: 34326454 PMCID: PMC8322329 DOI: 10.1038/s41598-021-94958-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 07/19/2021] [Indexed: 11/09/2022] Open
Abstract
Postzygotic mosaicism (PZM) in NIPBL is a strong source of causality for Cornelia de Lange syndrome (CdLS) that can have major clinical implications. Here, we further delineate the role of somatic mosaicism in CdLS by describing a series of 11 unreported patients with mosaic disease-causing variants in NIPBL and performing a retrospective cohort study from a Spanish CdLS diagnostic center. By reviewing the literature and combining our findings with previously published data, we demonstrate a negative selection against somatic deleterious NIPBL variants in blood. Furthermore, the analysis of all reported cases indicates an unusual high prevalence of mosaicism in CdLS, occurring in 13.1% of patients with a positive molecular diagnosis. It is worth noting that most of the affected individuals with mosaicism have a clinical phenotype at least as severe as those with constitutive pathogenic variants. However, the type of genetic change does not vary between germline and somatic events and, even in the presence of mosaicism, missense substitutions are located preferentially within the HEAT repeat domain of NIPBL. In conclusion, the high prevalence of mosaicism in CdLS as well as the disparity in tissue distribution provide a novel orientation for the clinical management and genetic counselling of families.
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Affiliation(s)
- Ana Latorre-Pellicer
- Unit of Clinical Genetics and Functional Genomics, Department of Pharmacology-Physiology, School of Medicine, Universidad de Zaragoza, CIBERER-GCV02 and IIS-Aragon, 50009, Zaragoza, Spain
| | - Marta Gil-Salvador
- Unit of Clinical Genetics and Functional Genomics, Department of Pharmacology-Physiology, School of Medicine, Universidad de Zaragoza, CIBERER-GCV02 and IIS-Aragon, 50009, Zaragoza, Spain
| | - Ilaria Parenti
- Institut für Humangenetik, Universitätsklinikum Essen, Universität Duisburg-Essen, Essen, Germany
| | - Cristina Lucia-Campos
- Unit of Clinical Genetics and Functional Genomics, Department of Pharmacology-Physiology, School of Medicine, Universidad de Zaragoza, CIBERER-GCV02 and IIS-Aragon, 50009, Zaragoza, Spain
| | - Laura Trujillano
- Unit of Clinical Genetics, Service of Paediatrics, Hospital Clínico Universitario Lozano Blesa, Department of Paediatrics, School of Medicine, Universidad de Zaragoza, CIBERER-GCV02 and IIS-Aragon, 50009, Zaragoza, Spain
| | - Iñigo Marcos-Alcalde
- Molecular Modelling Group, Centro de Biología Molecular Severo Ochoa, CBMSO (CSIC-UAM), 28049, Madrid, Spain
- Biosciences Research Institute, School of Experimental Sciences, Universidad Francisco de Vitoria, 28223, Pozuelo de Alarcón, Madrid, Spain
| | - María Arnedo
- Unit of Clinical Genetics and Functional Genomics, Department of Pharmacology-Physiology, School of Medicine, Universidad de Zaragoza, CIBERER-GCV02 and IIS-Aragon, 50009, Zaragoza, Spain
| | - Ángela Ascaso
- Unit of Clinical Genetics, Service of Paediatrics, Hospital Clínico Universitario Lozano Blesa, Department of Paediatrics, School of Medicine, Universidad de Zaragoza, CIBERER-GCV02 and IIS-Aragon, 50009, Zaragoza, Spain
| | - Ariadna Ayerza-Casas
- Unit of Paediatric Cardiology, Service of Paediatrics, Hospital Universitario Miguel Servet, 50009, Zaragoza, Spain
| | - Rebeca Antoñanzas-Pérez
- Unit of Clinical Genetics and Functional Genomics, Department of Pharmacology-Physiology, School of Medicine, Universidad de Zaragoza, CIBERER-GCV02 and IIS-Aragon, 50009, Zaragoza, Spain
| | - Cristina Gervasini
- Genetica Medica, Dipartimento di Scienze della Salute, Università degli Studi di Milano, Milano, Italy
| | - Maria Piccione
- Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties, University of Palermo, Palermo, Italy
| | - Milena Mariani
- Centro Fondazione Mariani per il Bambino Fragile, Department of Pediatrics, ASST-Lariana Sant'Anna Hospital, San Fermo della Battaglia (Como), Italy
| | - Axel Weber
- Institute of Human Genetics, Justus-Liebig-University, Giessen, Germany
| | - Deniz Kanber
- Institut für Humangenetik, Universitätsklinikum Essen, Universität Duisburg-Essen, Essen, Germany
| | - Alma Kuechler
- Institut für Humangenetik, Universitätsklinikum Essen, Universität Duisburg-Essen, Essen, Germany
| | - Martin Munteanu
- Institut für Humangenetik, Universitätsklinikum Essen, Universität Duisburg-Essen, Essen, Germany
| | - Katharina Khuller
- Institut für Humangenetik, Universitätsklinikum Essen, Universität Duisburg-Essen, Essen, Germany
| | - Gloria Bueno-Lozano
- Unit of Clinical Genetics, Service of Paediatrics, Hospital Clínico Universitario Lozano Blesa, Department of Paediatrics, School of Medicine, Universidad de Zaragoza, CIBERER-GCV02 and IIS-Aragon, 50009, Zaragoza, Spain
| | - Beatriz Puisac
- Unit of Clinical Genetics and Functional Genomics, Department of Pharmacology-Physiology, School of Medicine, Universidad de Zaragoza, CIBERER-GCV02 and IIS-Aragon, 50009, Zaragoza, Spain
| | - Paulino Gómez-Puertas
- Molecular Modelling Group, Centro de Biología Molecular Severo Ochoa, CBMSO (CSIC-UAM), 28049, Madrid, Spain
| | - Angelo Selicorni
- Centro Fondazione Mariani per il Bambino Fragile, Department of Pediatrics, ASST-Lariana Sant'Anna Hospital, San Fermo della Battaglia (Como), Italy
| | - Frank J Kaiser
- Institut für Humangenetik, Universitätsklinikum Essen, Universität Duisburg-Essen, Essen, Germany
- Essener Zentrum für Seltene Erkrankungen (EZSE), Universitätsmedizin Essen, Universitätsklinikum Essen, Essen, Germany
| | - Feliciano J Ramos
- Unit of Clinical Genetics, Service of Paediatrics, Hospital Clínico Universitario Lozano Blesa, Department of Paediatrics, School of Medicine, Universidad de Zaragoza, CIBERER-GCV02 and IIS-Aragon, 50009, Zaragoza, Spain.
| | - Juan Pié
- Unit of Clinical Genetics and Functional Genomics, Department of Pharmacology-Physiology, School of Medicine, Universidad de Zaragoza, CIBERER-GCV02 and IIS-Aragon, 50009, Zaragoza, Spain.
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Gu W, Wang L, Gu R, Ouyang H, Bao B, Zheng L, Xu B. Defects of cohesin loader lead to bone dysplasia associated with transcriptional disturbance. J Cell Physiol 2021; 236:8208-8225. [PMID: 34170011 DOI: 10.1002/jcp.30491] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 06/03/2021] [Accepted: 06/09/2021] [Indexed: 02/05/2023]
Abstract
Cohesin loader nipped-B-like protein (Nipbl) is increasingly recognized for its important role in development and cancer. Cornelia de Lange Syndrome (CdLS), mostly caused by heterozygous mutations of Nipbl, is an autosomal dominant disease characterized by multiorgan malformations. However, the regulatory role and underlying mechanism of Nipbl in skeletal development remain largely elusive. In this study, we constructed a Nipbl-a Cas9-knockout (KO) zebrafish, which displayed severe retardation of global growth and skeletal development. Deficiency of Nipbl remarkably compromised cell growth and survival, and osteogenic differentiation of mammalian osteoblast precursors. Furthermore, Nipbl depletion impaired the cell cycle process, and caused DNA damage accumulation and cellular senescence. In addition, nucleolar fibrillarin expression, global rRNA biogenesis, and protein translation were defective in the Nipbl-depleted osteoblast precursors. Interestingly, an integrated stress response inhibitor (ISRIB), partially rescued Nipbl depletion-induced cellular defects in proliferation and apoptosis, osteogenesis, and nucleolar function. Simultaneously, we performed transcriptome analysis of Nipbl deficiency on human neural crest cells and mouse embryonic fibroblasts in combination with Nipbl ChIP-Seq. We found that Nipbl deficiency caused thousands of differentially expressed genes including some important genes in bone and cartilage development. In conclusion, Nipbl deficiency compromised skeleton development through impairing osteoblast precursor cell proliferation and survival, and osteogenic differentiation, and also disturbing the expression of some osteogenesis-regulatory genes. Our study elucidated that Nipbl played a pivotal role in skeleton development, and supported the fact that treatment of ISRIB may provide an early intervention strategy to alleviate the bone dysplasia of CdLS.
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Affiliation(s)
- Weihuai Gu
- Hospital of Stomatology, Guanghua School of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Institute of Stomatological Research, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Lihong Wang
- Hospital of Stomatology, Guanghua School of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Institute of Stomatological Research, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Renjie Gu
- Hospital of Stomatology, Guanghua School of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Institute of Stomatological Research, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Huiya Ouyang
- Hospital of Stomatology, Guanghua School of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Institute of Stomatological Research, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Baicheng Bao
- Hospital of Stomatology, Orthodontic Department, Guanghua School of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Liwei Zheng
- State Key Laboratory of Oral Diseases, Department of Pediatric Dentistry, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Baoshan Xu
- Hospital of Stomatology, Guanghua School of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Institute of Stomatological Research, Sun Yat-sen University, Guangzhou, Guangdong, China
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Krawczynska N, Wierzba J, Wasag B. Genetic Mosaicism in a Group of Patients With Cornelia de Lange Syndrome. Front Pediatr 2019; 7:203. [PMID: 31157197 PMCID: PMC6530423 DOI: 10.3389/fped.2019.00203] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 05/01/2019] [Indexed: 12/22/2022] Open
Abstract
Background: Cornelia de Lange Syndrome (CdLS) is a heterogeneous disorder. Diverse expression of clinical symptoms can be caused by a variety of pathogenic variants located within the sequence of different genes correlated with the cohesin complex. Methods: Sixty-nine patients with confirmed clinical diagnosis of CdLS were enrolled in the study. Blood and buccal swab samples were collected for molecular studies. Mutational analysis was performed using the Next Generation (deep) Sequencing (NGS) covering 24 genes. In addition, the MLPA technique was applied to detect large rearrangements of NIPBL. Results: MLPA and NGS analysis were performed in 66 (95,7%) and 67 (97,1%) patients, respectively. Large rearrangements of NIPBL were not identified in the studied group. Germline pathogenic variants were detected in 18 (26,1%) patients. Fourteen variants (20,3%) were identified in NIPBL, two (2,9%) in SMC1A, and two (2,9%) in HDAC8. In total, 13 (18,8%) buccal swabs were suitable for deep sequencing. Mosaic variants were found in four (30,8%; 4/13) patients negative for germline alterations. Three mosaic substitutions were detected in NIPBL while one in KMT2A gene. Conclusions: Comprehensive and sensitive molecular techniques allow detecting novel pathogenic variants responsible for the molecular basis of CdLS. In addition, molecular testing of different tissues should be applied since such an approach allows detect mosaic variants specific for a subgroup of CdLS patients. Finally, to test possible pathogenicity of intronic variants, RNA analysis should be conducted.
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Affiliation(s)
- Natalia Krawczynska
- Department of Biology and Medical Genetics, Medical University of Gdańsk, Gdańsk, Poland.,Laboratory of Clinical Genetics, University Clinical Centre, Gdańsk, Poland
| | - Jolanta Wierzba
- Department of General Nursery, Medical University of Gdańsk, Gdańsk, Poland
| | - Bartosz Wasag
- Department of Biology and Medical Genetics, Medical University of Gdańsk, Gdańsk, Poland.,Laboratory of Clinical Genetics, University Clinical Centre, Gdańsk, Poland
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Masciadri M, Ficcadenti A, Milani D, Cogliati F, Divizia MT, Larizza L, Russo S. Recurrence and Familial Inheritance of Intronic NIPBL Pathogenic Variant Associated With Mild CdLS. Front Neurol 2018; 9:967. [PMID: 30538663 PMCID: PMC6277459 DOI: 10.3389/fneur.2018.00967] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 10/29/2018] [Indexed: 11/13/2022] Open
Abstract
Splicing pathogenic variants account for a notable fraction of NIPBL alterations underlying Cornelia de Lange syndrome but are likely underrepresented, due to overlooking of non-canonical intronic variants by traditional and contemporary sequencing methods. We describe five subjects, belonging to three families, displaying a mild Cornelia de Lange syndrome phenotype who carry the NIPBL pathogenic variant c.5329–15A>G, affecting the IVS27 branch site, yet reported in a single case. By RNA analysis we evidenced two alternative transcripts: the exon 28 in frame skipped transcript, described in the published case and an out-of-frame transcript retaining 14 nucleotides of IVS27 3′end. Even if both aberrant transcripts are at negligible levels, their presence justifies the CdLS phenotype shared by our patients consisting of borderline-mild cognitive impairment and slight but typical facial dysmorphisms. Transmission of the pathogenic variant from pauci-symptomatic mother to her siblings emphasizes the need of molecular diagnosis extended to deep intronic regions in patients with subtle but recognizable CdLS phenotype.
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Affiliation(s)
- Maura Masciadri
- Laboratorio di Ricerche di Citogenetica Medica e Genetica Molecolare, Istituto Auxologico Italiano (IRCCS) Milan, Italy
| | - Anna Ficcadenti
- Centro Regionale Malattie Rare, Azienda Ospedaliero Universitaria Ospedali Riuniti Ancona, Italy
| | - Donatella Milani
- Pediatric Highly Intensive Care Unit, Department of Pathophysiology and Transplantation, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico (IRCCS) Milan, Italy
| | - Francesca Cogliati
- Laboratorio di Ricerche di Citogenetica Medica e Genetica Molecolare, Istituto Auxologico Italiano (IRCCS) Milan, Italy
| | | | - Lidia Larizza
- Laboratorio di Ricerche di Citogenetica Medica e Genetica Molecolare, Istituto Auxologico Italiano (IRCCS) Milan, Italy
| | - Silvia Russo
- Laboratorio di Ricerche di Citogenetica Medica e Genetica Molecolare, Istituto Auxologico Italiano (IRCCS) Milan, Italy
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