1
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Ansari M, Faour KNW, Shimamura A, Grimes G, Kao EM, Denhoff ER, Blatnik A, Ben-Isvy D, Wang L, Helm BM, Firth H, Breman AM, Bijlsma EK, Iwata-Otsubo A, de Ravel TJL, Fusaro V, Fryer A, Nykamp K, Stühn LG, Haack TB, Korenke GC, Constantinou P, Bujakowska KM, Low KJ, Place E, Humberson J, Napier MP, Hoffman J, Juusola J, Deardorff MA, Shao W, Rockowitz S, Krantz I, Kaur M, Raible S, Dortenzio V, Kliesch S, Singer-Berk M, Groopman E, DiTroia S, Ballal S, Srivastava S, Rothfelder K, Biskup S, Rzasa J, Kerkhof J, McConkey H, Sadikovic B, Hilton S, Banka S, Tüttelmann F, Conrad DF, O'Donnell-Luria A, Talkowski ME, FitzPatrick DR, Boone PM. Heterozygous loss-of-function SMC3 variants are associated with variable growth and developmental features. HGG ADVANCES 2024; 5:100273. [PMID: 38297832 PMCID: PMC10876629 DOI: 10.1016/j.xhgg.2024.100273] [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: 11/08/2023] [Revised: 01/23/2024] [Accepted: 01/23/2024] [Indexed: 02/02/2024] Open
Abstract
Heterozygous missense variants and in-frame indels in SMC3 are a cause of Cornelia de Lange syndrome (CdLS), marked by intellectual disability, growth deficiency, and dysmorphism, via an apparent dominant-negative mechanism. However, the spectrum of manifestations associated with SMC3 loss-of-function variants has not been reported, leading to hypotheses of alternative phenotypes or even developmental lethality. We used matchmaking servers, patient registries, and other resources to identify individuals with heterozygous, predicted loss-of-function (pLoF) variants in SMC3, and analyzed population databases to characterize mutational intolerance in this gene. Here, we show that SMC3 behaves as an archetypal haploinsufficient gene: it is highly constrained against pLoF variants, strongly depleted for missense variants, and pLoF variants are associated with a range of developmental phenotypes. Among 14 individuals with SMC3 pLoF variants, phenotypes were variable but coalesced on low growth parameters, developmental delay/intellectual disability, and dysmorphism, reminiscent of atypical CdLS. Comparisons to individuals with SMC3 missense/in-frame indel variants demonstrated an overall milder presentation in pLoF carriers. Furthermore, several individuals harboring pLoF variants in SMC3 were nonpenetrant for growth, developmental, and/or dysmorphic features, and some had alternative symptomatologies with rational biological links to SMC3. Analyses of tumor and model system transcriptomic data and epigenetic data in a subset of cases suggest that SMC3 pLoF variants reduce SMC3 expression but do not strongly support clustering with functional genomic signatures of typical CdLS. Our finding of substantial population-scale LoF intolerance in concert with variable growth and developmental features in subjects with SMC3 pLoF variants expands the scope of cohesinopathies, informs on their allelic architecture, and suggests the existence of additional clearly LoF-constrained genes whose disease links will be confirmed only by multilayered genomic data paired with careful phenotyping.
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Affiliation(s)
- Morad Ansari
- South East Scotland Genetic Service, Western General Hospital, Edinburgh, UK; MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, UK
| | - Kamli N W Faour
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, USA; Cornelia de Lange Syndrome and Related Disorders Clinic, Boston Children's Hospital, Boston, MA, USA
| | - Akiko Shimamura
- Division of Hematology and Oncology, Boston Children's Hospital, Boston, MA, USA
| | - Graeme Grimes
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, UK
| | - Emeline M Kao
- Institutional Centers for Clinical and Translational Research, Boston Children's Hospital, Boston, MA, USA
| | - Erica R Denhoff
- Institutional Centers for Clinical and Translational Research, Boston Children's Hospital, Boston, MA, USA
| | - Ana Blatnik
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, UK; Department of Clinical Cancer Genetics, Institute of Oncology Ljubljana, Ljubljana, Slovenia
| | - Daniel Ben-Isvy
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA; Medical and Population Genetics, The Broad Institute of MIT and Harvard, Cambridge, MA, USA; Division of Medical Sciences, Harvard Medical School, Boston, MA, USA
| | - Lily Wang
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA; Medical and Population Genetics, The Broad Institute of MIT and Harvard, Cambridge, MA, USA; Division of Medical Sciences, Harvard Medical School, Boston, MA, USA
| | - Benjamin M Helm
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Helen Firth
- Clinical Genetics, Addenbrooke's Hospital, Cambridge University Hospitals, Cambridge, UK
| | - Amy M Breman
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Emilia K Bijlsma
- Department of Clinical Genetics, Leiden University Medical Centre, Leiden, the Netherlands
| | - Aiko Iwata-Otsubo
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Thomy J L de Ravel
- Centre for Human Genetics, UZ Leuven/Leuven University Hospitals, Leuven, Belgium
| | | | - Alan Fryer
- Department of Clinical Genetics, Alder Hey Children's Hospital Liverpool, Liverpool, UK
| | | | - Lara G Stühn
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
| | - Tobias B Haack
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
| | - G Christoph Korenke
- Department of Neuropaediatric and Metabolic Diseases, University Children's Hospital Oldenburg, Oldenburg, Germany
| | - Panayiotis Constantinou
- West of Scotland Centre for Genomic Medicine, Queen Elizabeth University Hospital, Glasgow, UK
| | | | - Karen J Low
- University Hospitals Bristol and Weston NHS Foundation Trust, Bristol, UK; University of Bristol, Bristol, UK
| | - Emily Place
- Massachusetts Eye and Ear Infirmary, Boston, MA, USA
| | | | | | | | | | - Matthew A Deardorff
- Departments of Pathology and Pediatrics, Children's Hospital Los Angeles and University of Southern California, Los Angeles, CA, USA
| | - Wanqing Shao
- Research Computing, Information Technology, Boston Children's Hospital, Boston, MA, USA
| | - Shira Rockowitz
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, USA; Research Computing, Information Technology, Boston Children's Hospital, Boston, MA, USA; The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA, USA
| | - Ian Krantz
- Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Maninder Kaur
- Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Sarah Raible
- Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | | | - Sabine Kliesch
- Department of Clinical and Surgical Andrology, Centre of Reproductive Medicine and Andrology, University Hospital Münster, Münster, Germany
| | - Moriel Singer-Berk
- Medical and Population Genetics, The Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Emily Groopman
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, USA; Medical and Population Genetics, The Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Stephanie DiTroia
- Medical and Population Genetics, The Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Sonia Ballal
- Cornelia de Lange Syndrome and Related Disorders Clinic, Boston Children's Hospital, Boston, MA, USA; Division of Gastroenterology, Boston Children's Hospital, Boston, MA, USA
| | - Siddharth Srivastava
- Cornelia de Lange Syndrome and Related Disorders Clinic, Boston Children's Hospital, Boston, MA, USA; Divison of Neurology, Boston Children's Hospital, Boston, MA, USA
| | | | - Saskia Biskup
- Zentrum für Humangenetik, Tübingen, Germany; Center for Genomics and Transcriptomics (CeGaT), Tübingen, Germany
| | - Jessica Rzasa
- Molecular Diagnostics Program and Verspeeten Clinical Genome Centre, London Health Sciences Centre, London, ON, Canada
| | - Jennifer Kerkhof
- Molecular Diagnostics Program and Verspeeten Clinical Genome Centre, London Health Sciences Centre, London, ON, Canada
| | - Haley McConkey
- Molecular Diagnostics Program and Verspeeten Clinical Genome Centre, London Health Sciences Centre, London, ON, Canada
| | - Bekim Sadikovic
- Molecular Diagnostics Program and Verspeeten Clinical Genome Centre, London Health Sciences Centre, London, ON, Canada
| | - Sarah Hilton
- Manchester Centre for Genomic Medicine, Manchester University NHS Foundation Trust, Health Innovation Manchester, Manchester, UK
| | - Siddharth Banka
- Manchester Centre for Genomic Medicine, Manchester University NHS Foundation Trust, Health Innovation Manchester, Manchester, UK; Division of Evolution, Infection, and Genomics, School of Biological Sciences, Faculty of Biology, Medicine, and Health, University of Manchester, Manchester, UK
| | - Frank Tüttelmann
- Institute of Reproductive Genetics, University of Münster, Münster, Germany
| | - Donald F Conrad
- Division of Genetics, Oregon National Primate Research Center, Oregon Health and Science University, Portland, OR, USA; Center for Embryonic Cell and Gene Therapy, Oregon Health and Science University, Portland, OR, USA
| | - Anne O'Donnell-Luria
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, USA; Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA; Medical and Population Genetics, The Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Michael E Talkowski
- Medical and Population Genetics, The Broad Institute of MIT and Harvard, Cambridge, MA, USA; Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - David R FitzPatrick
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, UK
| | - Philip M Boone
- Cornelia de Lange Syndrome and Related Disorders Clinic, Boston Children's Hospital, Boston, MA, USA; Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, USA; Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA; Medical and Population Genetics, The Broad Institute of MIT and Harvard, Cambridge, MA, USA.
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2
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Gibellato E, Cianci P, Mariani M, Parma B, Huisman S, Śmigiel R, Bisgaard AM, Massa V, Gervasini C, Moretti A, Cattoni A, Biondi A, Selicorni A. SMC1A epilepsy syndrome: clinical data from a large international cohort. Am J Med Genet A 2024:e63577. [PMID: 38421079 DOI: 10.1002/ajmg.a.63577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Revised: 01/24/2024] [Accepted: 02/08/2024] [Indexed: 03/02/2024]
Abstract
SMC1A epilepsy syndrome or developmental and epileptic encephalopathy-85 with or without midline brain defects (DEE85, OMIM #301044) is an X-linked neurologic disorder associated with mutations of the SMC1A gene, which is also responsible for about 5% of patients affected by Cornelia de Lange syndrome spectrum (CdLS). Only described in female patients, SMC1A epilepsy syndrome is characterized by the onset of severe refractory epileptic seizures in the first year of life, global developmental delay, a variable degree of intellectual disability, and dysmorphic facial features not typical of CdLS. This was a descriptive observational study for the largest international cohort with this specific disorder. The main goal of this study was to improve the knowledge of the natural history of this phenotype with particular attention to the psychomotor development and the epilepsy data. The analyzed cohort shows normal prenatal growth with the subsequent development of postnatal microcephaly. The incidence of neonatal problems (seizures and respiratory compromise) is considerable (51.4%). There is a significant prevalence of central nervous system (20%) and cardiovascular malformations (20%). Motor skills are generally delayed. The presence of drug-resistant epilepsy is confirmed; the therapeutic role of a ketogenic diet is still uncertain. The significant regression of previously acquired skills following the onset of seizures has been observed. Facial dysmorphisms are variable and no patient shows a classic CdLS phenotype. To sum up, SMC1A variants caused drug-resistant epilepsy in these patients, more than two-thirds of whom were shown to progress to developmental and epileptic encephalopathy. The SMC1A gene variants are all different from each other (apart from a couple of monozygotic twins), demonstrating the absence of a mutational hotspot in the SMC1A gene. Owing to the absence of phenotypic specificity, whole-exome sequencing is currently the diagnostic gold standard.
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Affiliation(s)
- Elisabetta Gibellato
- Pediatric Department, "Mariani" Center for Fragile Child, ASST Lariana, Sant'Anna Hospital, Como, Italy
- Department of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Paola Cianci
- Pediatric Department, "Mariani" Center for Fragile Child, ASST Lariana, Sant'Anna Hospital, Como, Italy
| | - Milena Mariani
- Pediatric Department, "Mariani" Center for Fragile Child, ASST Lariana, Sant'Anna Hospital, Como, Italy
| | - Barbara Parma
- Pediatric Department, "Mariani" Center for Fragile Child, ASST Lariana, Sant'Anna Hospital, Como, Italy
| | - Sylvia Huisman
- Pediatric Department, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Robert Śmigiel
- Pediatric Department, Endocrinology, Diabetology and Metabolic Diseases, Wroclaw Medical University, Wroclaw, Poland
| | - Anne-Marie Bisgaard
- Pediatric Department and Adolescent Medicine, Rigshospitalet, Copenhagen, Denmark
| | - Valentina Massa
- Department of Health Sciences, University of Milan, Milan, Italy
| | | | - Alex Moretti
- Department of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
- Pediatrics, Fondazione IRCCS San Gerardo dei Tintori, Monza, Italy
| | - Alessandro Cattoni
- Department of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
- Pediatrics, Fondazione IRCCS San Gerardo dei Tintori, Monza, Italy
| | - Andrea Biondi
- Department of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
- Pediatrics, Fondazione IRCCS San Gerardo dei Tintori, Monza, Italy
| | - Angelo Selicorni
- Pediatric Department, "Mariani" Center for Fragile Child, ASST Lariana, Sant'Anna Hospital, Como, Italy
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3
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Ansari M, Faour KNW, Shimamura A, Grimes G, Kao EM, Denhoff ER, Blatnik A, Ben-Isvy D, Wang L, Helm BM, Firth H, Breman AM, Bijlsma EK, Iwata-Otsubo A, de Ravel TJL, Fusaro V, Fryer A, Nykamp K, Stühn LG, Haack TB, Korenke GC, Constantinou P, Bujakowska KM, Low KJ, Place E, Humberson J, Napier MP, Hoffman J, Juusola J, Deardorff MA, Shao W, Rockowitz S, Krantz I, Kaur M, Raible S, Kliesch S, Singer-Berk M, Groopman E, DiTroia S, Ballal S, Srivastava S, Rothfelder K, Biskup S, Rzasa J, Kerkhof J, McConkey H, O'Donnell-Luria A, Sadikovic B, Hilton S, Banka S, Tüttelmann F, Conrad D, Talkowski ME, FitzPatrick DR, Boone PM. Heterozygous loss-of-function SMC3 variants are associated with variable and incompletely penetrant growth and developmental features. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.09.27.23294269. [PMID: 37808847 PMCID: PMC10557843 DOI: 10.1101/2023.09.27.23294269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Heterozygous missense variants and in-frame indels in SMC3 are a cause of Cornelia de Lange syndrome (CdLS), marked by intellectual disability, growth deficiency, and dysmorphism, via an apparent dominant-negative mechanism. However, the spectrum of manifestations associated with SMC3 loss-of-function variants has not been reported, leading to hypotheses of alternative phenotypes or even developmental lethality. We used matchmaking servers, patient registries, and other resources to identify individuals with heterozygous, predicted loss-of-function (pLoF) variants in SMC3, and analyzed population databases to characterize mutational intolerance in this gene. Here, we show that SMC3 behaves as an archetypal haploinsufficient gene: it is highly constrained against pLoF variants, strongly depleted for missense variants, and pLoF variants are associated with a range of developmental phenotypes. Among 13 individuals with SMC3 pLoF variants, phenotypes were variable but coalesced on low growth parameters, developmental delay/intellectual disability, and dysmorphism reminiscent of atypical CdLS. Comparisons to individuals with SMC3 missense/in-frame indel variants demonstrated a milder presentation in pLoF carriers. Furthermore, several individuals harboring pLoF variants in SMC3 were nonpenetrant for growth, developmental, and/or dysmorphic features, some instead having intriguing symptomatologies with rational biological links to SMC3 including bone marrow failure, acute myeloid leukemia, and Coats retinal vasculopathy. Analyses of transcriptomic and epigenetic data suggest that SMC3 pLoF variants reduce SMC3 expression but do not result in a blood DNA methylation signature clustering with that of CdLS, and that the global transcriptional signature of SMC3 loss is model-dependent. Our finding of substantial population-scale LoF intolerance in concert with variable penetrance in subjects with SMC3 pLoF variants expands the scope of cohesinopathies, informs on their allelic architecture, and suggests the existence of additional clearly LoF-constrained genes whose disease links will be confirmed only by multi-layered genomic data paired with careful phenotyping.
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Affiliation(s)
- Morad Ansari
- South East Scotland Genetic Service, Western General Hospital, Edinburgh, UK
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, UK
- These authors contributed equally
| | - Kamli N W Faour
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, US
- Cornelia de Lange Syndrome and Related Disorders Clinic, Boston Children's Hospital, Boston, MA, US
- These authors contributed equally
| | - Akiko Shimamura
- Division of Hematology and Oncology, Boston Children's Hospital, Boston, MA, US
| | - Graeme Grimes
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, UK
| | - Emeline M Kao
- Institutional Centers for Clinical and Translational Research, Boston Children's Hospital, Boston, MA, US
| | - Erica R Denhoff
- Institutional Centers for Clinical and Translational Research, Boston Children's Hospital, Boston, MA, US
| | - Ana Blatnik
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, UK
- Department of Clinical Cancer Genetics, Institute of Oncology Ljubljana, Ljubljana, SI
| | - Daniel Ben-Isvy
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, US
- Medical and Population Genetics, The Broad Institute of MIT and Harvard, Cambridge, MA, US
- Division of Medical Sciences, Harvard Medical School, Boston, MA, US
| | - Lily Wang
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, US
- Medical and Population Genetics, The Broad Institute of MIT and Harvard, Cambridge, MA, US
- Division of Medical Sciences, Harvard Medical School, Boston, MA, US
| | - Benjamin M Helm
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, US
| | - Helen Firth
- Clinical Genetics, Addenbrooke's Hospital, Cambridge University Hospitals, Cambridge, UK
| | - Amy M Breman
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, US
| | - Emilia K Bijlsma
- Department of Clinical Genetics, Leiden University Medical Centre, Leiden, NL
| | - Aiko Iwata-Otsubo
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, US
| | - Thomy J L de Ravel
- Centre for Human Genetics, UZ Leuven/ Leuven University Hospitals, Leuven, BE
| | | | - Alan Fryer
- Department of Clinical Genetics, Alder Hey Children's Hospital Liverpool, Liverpool, UK
| | | | - Lara G Stühn
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Tuebingen, DE
| | - Tobias B Haack
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Tuebingen, DE
| | - G Christoph Korenke
- University Children's Hospital Oldenburg, Department of Neuropaediatric and Metabolic Diseases, University Children's Hospital Oldenburg, Oldenburg, DE
| | - Panayiotis Constantinou
- West of Scotland Centre for Genomic Medicine, Queen Elizabeth University Hospital, Glasgow, UK
| | | | - Karen J Low
- University Hospitals Bristol and Weston NHS Foundation Trust, Bristol, UK
- University of Bristol, Bristol, UK
| | - Emily Place
- Massachusetts Eye and Ear Infirmary, Boston, MA, US
| | | | | | | | | | - Matthew A Deardorff
- Departments of Pathology and Pediatrics, Children's Hospital Los Angeles and University of Southern California, Los Angeles, CA, US
| | - Wanqing Shao
- Research Computing, Information Technology, Boston Children's Hospital, Boston, MA, US
| | - Shira Rockowitz
- Research Computing, Information Technology, Boston Children's Hospital, Boston, MA, US
- The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA, US
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, US
| | - Ian Krantz
- Children's Hospital of Philadelphia, Philadelphia, PA, US
| | - Maninder Kaur
- Children's Hospital of Philadelphia, Philadelphia, PA, US
| | - Sarah Raible
- Children's Hospital of Philadelphia, Philadelphia, PA, US
| | - Sabine Kliesch
- Department of Clinical and Surgical Andrology, Centre of Reproductive Medicine and Andrology, University Hospital Münster, Münster, DE
| | - Moriel Singer-Berk
- Medical and Population Genetics, The Broad Institute of MIT and Harvard, Cambridge, MA, US
| | - Emily Groopman
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, US
- Medical and Population Genetics, The Broad Institute of MIT and Harvard, Cambridge, MA, US
| | - Stephanie DiTroia
- Medical and Population Genetics, The Broad Institute of MIT and Harvard, Cambridge, MA, US
| | - Sonia Ballal
- Cornelia de Lange Syndrome and Related Disorders Clinic, Boston Children's Hospital, Boston, MA, US
- Division of Gastroenterology, Boston Children's Hospital, Boston, MA, US
| | - Siddharth Srivastava
- Cornelia de Lange Syndrome and Related Disorders Clinic, Boston Children's Hospital, Boston, MA, US
- Divison of Neurology, Boston Children's Hospital, Boston, MA, US
| | | | - Saskia Biskup
- Zentrum für Humangenetik, Tübingen, DE
- Center for Genomics and Transcriptomics (CeGaT), Tübingen, DE
| | - Jessica Rzasa
- Molecular Diagnostics Program and Verspeeten Clinical Genome Centre, LHSC, London, CA
| | - Jennifer Kerkhof
- Molecular Diagnostics Program and Verspeeten Clinical Genome Centre, LHSC, London, CA
| | - Haley McConkey
- Molecular Diagnostics Program and Verspeeten Clinical Genome Centre, LHSC, London, CA
| | - Anne O'Donnell-Luria
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, US
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, US
- Medical and Population Genetics, The Broad Institute of MIT and Harvard, Cambridge, MA, US
| | - Bekim Sadikovic
- Molecular Diagnostics Program and Verspeeten Clinical Genome Centre, LHSC, London, CA
| | | | | | - Frank Tüttelmann
- Institute of Reproductive Genetics, University of Münster, Münster, DE
| | - Donald Conrad
- Division of Genetics, Oregon National Primate Research Center, Oregon Health and Science University, Portland, OR, US
- Center for Embryonic Cell and Gene Therapy, Oregon Health and Science University, Portland, OR, US
| | - Michael E Talkowski
- Medical and Population Genetics, The Broad Institute of MIT and Harvard, Cambridge, MA, US
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, US
| | - David R FitzPatrick
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, UK
- These authors contributed equally
| | - Philip M Boone
- Cornelia de Lange Syndrome and Related Disorders Clinic, Boston Children's Hospital, Boston, MA, US
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, US
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, US
- Medical and Population Genetics, The Broad Institute of MIT and Harvard, Cambridge, MA, US
- These authors contributed equally
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4
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Bozarth XL, Lopez J, Fang H, Lee-Eng J, Duan Z, Deng X. Phenotypes and Genotypes in Patients with SMC1A-Related Developmental and Epileptic Encephalopathy. Genes (Basel) 2023; 14:852. [PMID: 37107610 PMCID: PMC10138066 DOI: 10.3390/genes14040852] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 03/27/2023] [Accepted: 03/29/2023] [Indexed: 04/05/2023] Open
Abstract
The X-linked SMC1A gene encodes a core subunit of the cohesin complex that plays a pivotal role in genome organization and gene regulation. Pathogenic variants in SMC1A are often dominant-negative and cause Cornelia de Lange syndrome (CdLS) with growth retardation and typical facial features; however, rare SMC1A variants cause a developmental and epileptic encephalopathy (DEE) with intractable early-onset epilepsy that is absent in CdLS. Unlike the male-to-female ratio of 1:2 in those with CdLS associated with dominant-negative SMC1A variants, SMC1A-DEE loss-of-function (LOF) variants are found exclusively in females due to presumed lethality in males. It is unclear how different SMC1A variants cause CdLS or DEE. Here, we report on phenotypes and genotypes of three females with DEE and de novo SMC1A variants, including a novel splice-site variant. We also summarize 41 known SMC1A-DEE variants to characterize common and patient-specific features. Interestingly, compared to 33 LOFs detected throughout the gene, 7/8 non-LOFs are specifically located in the N/C-terminal ATPase head or the central hinge domain, both of which are predicted to affect cohesin assembly, thus mimicking LOFs. Along with the characterization of X-chromosome inactivation (XCI) and SMC1A transcription, these variants strongly suggest that a differential SMC1A dosage effect of SMC1A-DEE variants is closely associated with the manifestation of DEE phenotypes.
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Affiliation(s)
- Xiuhua L. Bozarth
- Division of Neurology, Seattle Children’s Hospital, University of Washington, Seattle, WA 98105, USA
| | - Jonathan Lopez
- Division of Neurology, Seattle Children’s Hospital, University of Washington, Seattle, WA 98105, USA
| | - He Fang
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA 98195, USA
| | - Jacqueline Lee-Eng
- Division of Neurology, Seattle Children’s Hospital, University of Washington, Seattle, WA 98105, USA
| | - Zhijun Duan
- Division of Hematology, University of Washington, Seattle, WA 98195, USA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98195, USA
| | - Xinxian Deng
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA 98195, USA
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5
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Hieu NLT, Thu NTM, Ngan LTA, Van LTK, Huy DP, Linh PTT, Mai NTQ, Hien HTD, Hang DTT. Genetic analysis using targeted exome sequencing of 53 Vietnamese children with developmental and epileptic encephalopathies. Am J Med Genet A 2022; 188:2048-2060. [PMID: 35365919 DOI: 10.1002/ajmg.a.62741] [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: 08/15/2021] [Revised: 01/14/2022] [Accepted: 03/13/2022] [Indexed: 11/07/2022]
Abstract
Developmental and epileptic encephalopathies (DEE) refers to a group of rare and severe neurodevelopmental disorders where genetic etiologies can play a major role. This study aimed to elucidate the genetic etiologies of a cohort of 53 Vietnamese patients with DEE. All patients were classified into known electroclinical syndromes where possible. Exome sequencing (ES) followed by a targeted analysis on 294 DEE-related genes was then performed. Patients with identified causative variants were followed for 6 months to determine the impact of genetic testing on their treatment. The diagnostic yield was 38.0% (20/53), which was significantly higher in the earlier onset group (<12 months) than in the later onset group (≥12 months). The 19 identified variants belonged to 11 genes with various cellular functions. Genes encoding ion channels especially sodium voltage-gated channel were the most frequently involved. Most variants were missense variants and located in key protein functional domains. Four variants were novel and four had been reported previously but in different phenotypes. Within 6 months of further follow-up, treatment changes were applied for six patients based on the identified disease-causing variants, with five patients showing a positive impact. This is the first study in Vietnam to analyze the genetics of DEE. This study confirms the strong involvement of genetic etiologies in DEE, especially early onset DEE. The study also contributes to clarify the genotype-phenotype correlations of DEE and highlights the efficacy of targeted ES in the diagnosis and treatment of DEE.
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Affiliation(s)
- Nguyen Le Trung Hieu
- Neurology Department, Children Hospital 2, Ho Chi Minh City, Vietnam.,University of Medicine and Pharmacy, Ho Chi Minh City, Vietnam
| | | | - Le Tran Anh Ngan
- Neurology Department, Children Hospital 2, Ho Chi Minh City, Vietnam
| | - Le Thi Khanh Van
- Neurology Department, Children Hospital 2, Ho Chi Minh City, Vietnam
| | - Do Phuoc Huy
- Medical Genetics Institute, Ho Chi Minh City, Vietnam
| | - Pham Thi Truc Linh
- Functional Genomic Unit, DNA Medical Technology Company, Ho Chi Minh City, Vietnam
| | - Nguyen Thi Quynh Mai
- Research Center for Genetics and Reproductive Health, School of Medicine, Vietnam National University, Ho Chi Minh City, Vietnam
| | - Huynh Thi Dieu Hien
- Research Center for Genetics and Reproductive Health, School of Medicine, Vietnam National University, Ho Chi Minh City, Vietnam
| | - Do Thi Thu Hang
- Research Center for Genetics and Reproductive Health, School of Medicine, Vietnam National University, Ho Chi Minh City, Vietnam
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Elwan M, Fowkes R, Lewis-Smith D, Winder A, Baker MR, Thomas RH. Late-onset cluster seizures and intellectual disability associated with a novel truncation variant in SMC1A. Epilepsy Behav Rep 2022; 19:100556. [PMID: 35712061 PMCID: PMC9194849 DOI: 10.1016/j.ebr.2022.100556] [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: 10/17/2021] [Revised: 05/08/2022] [Accepted: 05/31/2022] [Indexed: 11/25/2022] Open
Abstract
Epilepsy due to truncating SMC1A variants can present with onset in later childhood. People with to truncating SMC1A variants can have normal development prior to presentation. Seizures occur periodically in clusters and are poorly responsive to antiseizure medications.
SMC1A variants are known to cause Cornelia de Lange Syndrome (CdLS) which encompasses a clinical spectrum of intellectual disability, dysmorphic features (long or thick eyebrows, a hypomorphic philtrum and small nose) and, in some cases, epilepsy. More recently, SMC1A truncating variants have been described as the cause of a neurodevelopmental disorder with early-childhood onset drug-resistant epilepsy with seizures that occur in clusters, similar to that seen in PCDH19-related epilepsy, but without the classical features of CdLS. Here, we report the case of a 28-year-old woman with a de novo heterozygous truncating variant in SMC1A who unusually presented with seizures at the late age of 12 years and had normal development into adulthood.
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Affiliation(s)
- Menatalla Elwan
- Department of Neurology, Royal Victoria Infirmary, Newcastle upon Tyne NE1 4LP, United Kingdom
| | - Ross Fowkes
- Department of Neurology, Royal Victoria Infirmary, Newcastle upon Tyne NE1 4LP, United Kingdom
| | - David Lewis-Smith
- Department of Neurology, Royal Victoria Infirmary, Newcastle upon Tyne NE1 4LP, United Kingdom
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Amy Winder
- Department of Clinical Neurophysiology, Royal Victoria Infirmary, Newcastle upon Tyne NE1 4LP, United Kingdom
| | - Mark R. Baker
- Department of Neurology, Royal Victoria Infirmary, Newcastle upon Tyne NE1 4LP, United Kingdom
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
- Department of Clinical Neurophysiology, Royal Victoria Infirmary, Newcastle upon Tyne NE1 4LP, United Kingdom
| | - Rhys H. Thomas
- Department of Neurology, Royal Victoria Infirmary, Newcastle upon Tyne NE1 4LP, United Kingdom
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
- Wellcome Centre for Mitochondrial Research, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
- Corresponding author at: Intermediate Clinical Lecturer and Honorary Consultant in Epilepsy, Translational and Clinical Research Institute, Newcastle University, Henry Wellcome Building, Framlington Place, Newcastle upon Tyne NE2 4HH.
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Hirose S, Tanaka Y, Shibata M, Kimura Y, Ishikawa M, Higurashi N, Yamamoto T, Ichise E, Chiyonobu T, Ishii A. Application of induced pluripotent stem cells in epilepsy. Mol Cell Neurosci 2020; 108:103535. [DOI: 10.1016/j.mcn.2020.103535] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 07/10/2020] [Accepted: 07/31/2020] [Indexed: 02/06/2023] Open
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Abstract
Structural Maintenance of Chromosomes (SMCs) are part of a large family of ring complexes that participates in a number of DNA transactions. Among SMCs, SMC1A gene is unique. It encodes a subunit of the cohesin-core complex that tethers sister chromatids together to ensure correct chromosome segregation in both mitosis and meiosis. As a member of the cohesin ring, SMC1A takes part in gene transcription regulation and genome organization; and it participates in the DNA Damage Repair (DDR) pathway, being phosphorylated by Ataxia Telangiectasia Mutated (ATM) and Ataxia Telangiectasia and Rad3 Related (ATR) threonine/serine kinases. It is also a component of the Recombination protein complex (RC-1) involved in DNA repair by recombination. SMC1A pathogenic variants have been described in Cornelia de Lange syndrome (CdLS), a human rare disease, and recently SMC1A variants have been associated with epilepsy or resembling Rett syndrome phenotype. Finally, SMC1A variants have been identified in several human cancers. In this review, our current knowledge of the SMC1A gene has been summarized.
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Affiliation(s)
- Antonio Musio
- Institute for Genetic and Biomedical Research (IRGB), National Research Council (CNR), Pisa, Italy.
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