1
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Zaker E, Nouri N, Movahedinia M, Dadbinpour A, Vahidi Mehrjardi MY. Type 1 early infantile epileptic encephalopathy: A case report and literature review. Mol Genet Genomic Med 2024; 12:e2412. [PMID: 38400608 PMCID: PMC10891437 DOI: 10.1002/mgg3.2412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Revised: 02/09/2024] [Accepted: 02/13/2024] [Indexed: 02/25/2024] Open
Abstract
BACKGROUND Variants in the Aristaless-related homeobox (ARX) gene lead to a variety of phenotypes, with intellectual disability being a steady feature. Other features can include severe epilepsy, spasticity, movement disorders, hydranencephaly, and ambiguous genitalia in males. X-linked Ohtahara syndrome or Type 1 early infantile epileptic encephalopathy (EIEE1) is a severe early-onset epileptic encephalopathy with arrested psychomotor development caused by hemizygous mutations in the ARX gene, which encodes a transcription factor in fundamental brain developmental processes. METHODS We presented a case report of a 2-year-old boy who exhibited symptoms such as microcephaly, seizures, and severe multifocal epileptic abnormalities, and genetic techniques such as autozygosity mapping, Sanger sequencing, and whole-exome sequencing. RESULTS We confirmed that the patient had the NM_139058.3:c.84C>A; p.(Cys28Ter) mutation in the ARX gene. CONCLUSION The patient with EIEE1 had physical symptoms and hypsarrhythmia on electroencephalogram. Genetic testing identified a causative mutation in the ARX gene, emphasizing the role of genetic testing in EIEE diagnosis.
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Affiliation(s)
- Erfan Zaker
- Department of Medical Genetics, Faculty of MedicineShahid Sadoughi University of Medical SciencesYazdIran
| | - Negar Nouri
- Department of Medical Genetics, Faculty of MedicineShahid Sadoughi University of Medical SciencesYazdIran
| | - Mojtaba Movahedinia
- Department of Children Growth Disorder Research CenterShahid Sadoughi University of Medical SciencesYazdIran
| | - Ali Dadbinpour
- Department of Medical GeneticsSchool of MedicineShahid Sadoughi University of Medical SciencesYazdIran
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2
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Lim Y. Transcription factors in microcephaly. Front Neurosci 2023; 17:1302033. [PMID: 38094004 PMCID: PMC10716367 DOI: 10.3389/fnins.2023.1302033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 11/06/2023] [Indexed: 02/01/2024] Open
Abstract
Higher cognition in humans, compared to other primates, is often attributed to an increased brain size, especially forebrain cortical surface area. Brain size is determined through highly orchestrated developmental processes, including neural stem cell proliferation, differentiation, migration, lamination, arborization, and apoptosis. Disruption in these processes often results in either a small (microcephaly) or large (megalencephaly) brain. One of the key mechanisms controlling these developmental processes is the spatial and temporal transcriptional regulation of critical genes. In humans, microcephaly is defined as a condition with a significantly smaller head circumference compared to the average head size of a given age and sex group. A growing number of genes are identified as associated with microcephaly, and among them are those involved in transcriptional regulation. In this review, a subset of genes encoding transcription factors (e.g., homeobox-, basic helix-loop-helix-, forkhead box-, high mobility group box-, and zinc finger domain-containing transcription factors), whose functions are important for cortical development and implicated in microcephaly, are discussed.
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Affiliation(s)
- Youngshin Lim
- Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, United States
- Department of Biomedical Science Education, Charles R. Drew University of Medicine and Science, Los Angeles, CA, United States
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3
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Brandes N, Goldman G, Wang CH, Ye CJ, Ntranos V. Genome-wide prediction of disease variant effects with a deep protein language model. Nat Genet 2023; 55:1512-1522. [PMID: 37563329 PMCID: PMC10484790 DOI: 10.1038/s41588-023-01465-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 07/05/2023] [Indexed: 08/12/2023]
Abstract
Predicting the effects of coding variants is a major challenge. While recent deep-learning models have improved variant effect prediction accuracy, they cannot analyze all coding variants due to dependency on close homologs or software limitations. Here we developed a workflow using ESM1b, a 650-million-parameter protein language model, to predict all ~450 million possible missense variant effects in the human genome, and made all predictions available on a web portal. ESM1b outperformed existing methods in classifying ~150,000 ClinVar/HGMD missense variants as pathogenic or benign and predicting measurements across 28 deep mutational scan datasets. We further annotated ~2 million variants as damaging only in specific protein isoforms, demonstrating the importance of considering all isoforms when predicting variant effects. Our approach also generalizes to more complex coding variants such as in-frame indels and stop-gains. Together, these results establish protein language models as an effective, accurate and general approach to predicting variant effects.
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Affiliation(s)
- Nadav Brandes
- Division of Rheumatology, Department of Medicine, University of California, San Francisco, San Francisco, CA, USA
| | - Grant Goldman
- Biological and Medical Informatics Graduate Program, University of California, San Francisco, San Francisco, CA, USA
| | - Charlotte H Wang
- Biomedical Sciences Graduate Program, University of California, San Francisco, San Francisco, CA, USA
| | - Chun Jimmie Ye
- Division of Rheumatology, Department of Medicine, University of California, San Francisco, San Francisco, CA, USA.
- Bakar Computational Health Sciences Institute, University of California, San Francisco, San Francisco, CA, USA.
- Parker Institute for Cancer Immunotherapy, University of California, San Francisco, San Francisco, CA, USA.
- Gladstone-UCSF Institute of Genomic Immunology, San Francisco, CA, USA.
- Institute for Human Genetics, University of California, San Francisco, San Francisco, CA, USA.
- Department of Epidemiology & Biostatistics, University of California, San Francisco, San Francisco, CA, USA.
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA, USA.
| | - Vasilis Ntranos
- Bakar Computational Health Sciences Institute, University of California, San Francisco, San Francisco, CA, USA.
- Department of Epidemiology & Biostatistics, University of California, San Francisco, San Francisco, CA, USA.
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA, USA.
- Diabetes Center, University of California, San Francisco, San Francisco, CA, USA.
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4
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Fujimura K, Guise AJ, Nakayama T, Schlaffner CN, Meziani A, Kumar M, Cheng L, Vaughan DJ, Kodani A, Van Haren S, Parker K, Levy O, Durbin AF, Bosch I, Gehrke L, Steen H, Mochida GH, Steen JA. Integrative systems biology characterizes immune-mediated neurodevelopmental changes in murine Zika virus microcephaly. iScience 2023; 26:106909. [PMID: 37332674 PMCID: PMC10275723 DOI: 10.1016/j.isci.2023.106909] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 02/12/2023] [Accepted: 05/12/2023] [Indexed: 06/20/2023] Open
Abstract
Characterizing perturbation of molecular pathways in congenital Zika virus (ZIKV) infection is critical for improved therapeutic approaches. Leveraging integrative systems biology, proteomics, and RNA-seq, we analyzed embryonic brain tissues from an immunocompetent, wild-type congenital ZIKV infection mouse model. ZIKV induced a robust immune response accompanied by the downregulation of critical neurodevelopmental gene programs. We identified a negative correlation between ZIKV polyprotein abundance and host cell cycle-inducing proteins. We further captured the downregulation of genes/proteins, many of which are known to be causative for human microcephaly, including Eomesodermin/T-box Brain Protein 2 (EOMES/TBR2) and Neuronal Differentiation 2 (NEUROD2). Disturbances of distinct molecular pathways in neural progenitors and post-mitotic neurons may contribute to complex brain phenotype of congenital ZIKV infection. Overall, this report on protein- and transcript-level dynamics enhances understanding of the ZIKV immunopathological landscape through characterization of fetal immune response in the developing brain.
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Affiliation(s)
- Kimino Fujimura
- F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA
- Division of Genetics and Genomics and The Manton Center for Orphan Disease, Boston Children’s Hospital, Department of Pediatrics, Harvard Medical School, Boston, MA, USA
- Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan
- Department of Pediatrics, Shin-Yurigaoka General Hospital, Kanagawa, Japan
| | - Amanda J. Guise
- F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Tojo Nakayama
- Division of Genetics and Genomics and The Manton Center for Orphan Disease, Boston Children’s Hospital, Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Christoph N. Schlaffner
- F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Anais Meziani
- F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Mukesh Kumar
- F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Long Cheng
- F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Dylan J. Vaughan
- Division of Genetics and Genomics and The Manton Center for Orphan Disease, Boston Children’s Hospital, Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Andrew Kodani
- Center for Pediatric Neurological Disease Research and Department of Cell and Molecular Biology, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Simon Van Haren
- Precision Vaccines Program, Division of Infectious Diseases, Boston Children’s Hospital, Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | | | - Ofer Levy
- Precision Vaccines Program, Division of Infectious Diseases, Boston Children’s Hospital, Department of Pediatrics, Harvard Medical School, Boston, MA, USA
- Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, MA, USA
| | - Ann F. Durbin
- Department of Microbiology, Harvard Medical School, Boston, MA, USA
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Irene Bosch
- Department of Microbiology, Harvard Medical School, Boston, MA, USA
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Lee Gehrke
- Department of Microbiology, Harvard Medical School, Boston, MA, USA
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Hanno Steen
- Precision Vaccines Program, Division of Infectious Diseases, Boston Children’s Hospital, Department of Pediatrics, Harvard Medical School, Boston, MA, USA
- Department of Pathology, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Ganeshwaran H. Mochida
- Division of Genetics and Genomics and The Manton Center for Orphan Disease, Boston Children’s Hospital, Department of Pediatrics, Harvard Medical School, Boston, MA, USA
- Pediatric Neurology Unit, Department of Neurology, Massachusetts General Hospital, Boston, MA, USA
| | - Judith A. Steen
- F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA
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5
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The genetics of monogenic intestinal epithelial disorders. Hum Genet 2022; 142:613-654. [PMID: 36422736 PMCID: PMC10182130 DOI: 10.1007/s00439-022-02501-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Accepted: 10/23/2022] [Indexed: 11/27/2022]
Abstract
Monogenic intestinal epithelial disorders, also known as congenital diarrheas and enteropathies (CoDEs), are a group of rare diseases that result from mutations in genes that primarily affect intestinal epithelial cell function. Patients with CoDE disorders generally present with infantile-onset diarrhea and poor growth, and often require intensive fluid and nutritional management. CoDE disorders can be classified into several categories that relate to broad areas of epithelial function, structure, and development. The advent of accessible and low-cost genetic sequencing has accelerated discovery in the field with over 45 different genes now associated with CoDE disorders. Despite this increasing knowledge in the causal genetics of disease, the underlying cellular pathophysiology remains incompletely understood for many disorders. Consequently, clinical management options for CoDE disorders are currently limited and there is an urgent need for new and disorder-specific therapies. In this review, we provide a general overview of CoDE disorders, including a historical perspective of the field and relationship to other monogenic disorders of the intestine. We describe the genetics, clinical presentation, and known pathophysiology for specific disorders. Lastly, we describe the major challenges relating to CoDE disorders, briefly outline key areas that need further study, and provide a perspective on the future genetic and therapeutic landscape.
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6
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Showpnil IA, Selich-Anderson J, Taslim C, Boone MA, Crow JC, Theisen ER, Lessnick SL. EWS/FLI mediated reprogramming of 3D chromatin promotes an altered transcriptional state in Ewing sarcoma. Nucleic Acids Res 2022; 50:9814-9837. [PMID: 36124657 PMCID: PMC9508825 DOI: 10.1093/nar/gkac747] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 08/10/2022] [Accepted: 08/23/2022] [Indexed: 12/13/2022] Open
Abstract
Ewing sarcoma is a prototypical fusion transcription factor-associated pediatric cancer that expresses EWS/FLI or a highly related FET/ETS chimera. EWS/FLI dysregulates transcription to induce and maintain sarcomagenesis, but the mechanisms utilized are not fully understood. We therefore sought to define the global effects of EWS/FLI on chromatin conformation and transcription in Ewing sarcoma cells using a well-validated ‘knock-down/rescue’ model of EWS/FLI function in combination with next generation sequencing assays to evaluate how the chromatin landscape changes with loss, and recovery, of EWS/FLI expression. We found that EWS/FLI (and EWS/ERG) genomic localization is largely conserved across multiple patient-derived Ewing sarcoma cell lines. This EWS/FLI binding signature is associated with establishment of topologically-associated domain (TAD) boundaries, compartment activation, enhancer-promoter looping that involve both intra- and inter-TAD interactions, and gene activation. In addition, EWS/FLI co-localizes with the loop-extrusion factor cohesin to promote chromatin loops and TAD boundaries. Importantly, local chromatin features provide the basis for transcriptional heterogeneity in regulation of direct EWS/FLI target genes across different Ewing sarcoma cell lines. These data demonstrate a key role of EWS/FLI in mediating genome-wide changes in chromatin configuration and support the notion that fusion transcription factors serve as master regulators of three-dimensional reprogramming of chromatin.
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Affiliation(s)
- Iftekhar A Showpnil
- Center for Childhood Cancer and Blood Diseases, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA.,Molecular, Cellular, and Developmental Biology Graduate Program, The Ohio State University, Columbus, OH 43210, USA
| | - Julia Selich-Anderson
- Center for Childhood Cancer and Blood Diseases, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Cenny Taslim
- Center for Childhood Cancer and Blood Diseases, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Megann A Boone
- Center for Childhood Cancer and Blood Diseases, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA.,Biomedical Sciences Graduate Program, The Ohio State University, Columbus, OH 43210, USA
| | - Jesse C Crow
- Center for Childhood Cancer and Blood Diseases, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Emily R Theisen
- Center for Childhood Cancer and Blood Diseases, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA.,Molecular, Cellular, and Developmental Biology Graduate Program, The Ohio State University, Columbus, OH 43210, USA.,Biomedical Sciences Graduate Program, The Ohio State University, Columbus, OH 43210, USA.,Department of Pediatrics, The Ohio State University, Columbus, OH 43210, USA
| | - Stephen L Lessnick
- Center for Childhood Cancer and Blood Diseases, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA.,Molecular, Cellular, and Developmental Biology Graduate Program, The Ohio State University, Columbus, OH 43210, USA.,Biomedical Sciences Graduate Program, The Ohio State University, Columbus, OH 43210, USA.,Department of Pediatrics, The Ohio State University, Columbus, OH 43210, USA.,Division of Pediatric Heme/Onc/BMT, The Ohio State University College of Medicine, Columbus, OH 43210, USA
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7
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Leung RF, George AM, Roussel EM, Faux MC, Wigle JT, Eisenstat DD. Genetic Regulation of Vertebrate Forebrain Development by Homeobox Genes. Front Neurosci 2022; 16:843794. [PMID: 35546872 PMCID: PMC9081933 DOI: 10.3389/fnins.2022.843794] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 03/14/2022] [Indexed: 01/19/2023] Open
Abstract
Forebrain development in vertebrates is regulated by transcription factors encoded by homeobox, bHLH and forkhead gene families throughout the progressive and overlapping stages of neural induction and patterning, regional specification and generation of neurons and glia from central nervous system (CNS) progenitor cells. Moreover, cell fate decisions, differentiation and migration of these committed CNS progenitors are controlled by the gene regulatory networks that are regulated by various homeodomain-containing transcription factors, including but not limited to those of the Pax (paired), Nkx, Otx (orthodenticle), Gsx/Gsh (genetic screened), and Dlx (distal-less) homeobox gene families. This comprehensive review outlines the integral role of key homeobox transcription factors and their target genes on forebrain development, focused primarily on the telencephalon. Furthermore, links of these transcription factors to human diseases, such as neurodevelopmental disorders and brain tumors are provided.
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Affiliation(s)
- Ryan F. Leung
- Murdoch Children’s Research Institute, The Royal Children’s Hospital Melbourne, Parkville, VIC, Australia
- Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia
| | - Ankita M. George
- Murdoch Children’s Research Institute, The Royal Children’s Hospital Melbourne, Parkville, VIC, Australia
| | - Enola M. Roussel
- Murdoch Children’s Research Institute, The Royal Children’s Hospital Melbourne, Parkville, VIC, Australia
| | - Maree C. Faux
- Murdoch Children’s Research Institute, The Royal Children’s Hospital Melbourne, Parkville, VIC, Australia
- Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia
- Department of Surgery, Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, Australia
| | - Jeffrey T. Wigle
- Department of Biochemistry and Medical Genetics, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB, Canada
| | - David D. Eisenstat
- Murdoch Children’s Research Institute, The Royal Children’s Hospital Melbourne, Parkville, VIC, Australia
- Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia
- Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada
- Department of Pediatrics, University of Alberta, Edmonton, AB, Canada
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8
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Fischer J, Di Donato N. Diagnostic pitfalls in patients with malformations of cortical development. Eur J Paediatr Neurol 2022; 37:123-128. [PMID: 35228169 DOI: 10.1016/j.ejpn.2022.01.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 01/25/2022] [Accepted: 01/26/2022] [Indexed: 11/27/2022]
Abstract
Malformations of cortical development (MCDs) are a major source of morbidity and mortality in the pediatric patient cohort. Correct diagnosis of the cause is essential for symptom management, disease prognosis and family counselling but is frequently hampered due to numerous potential pitfalls in the diagnostic process. This review highlights potential problems that either prevent the establishment of a diagnosis or are the sources of diagnostic errors. The focus is placed on hereditary causes of MCDs and strategies will be proposed to circumvent potential diagnostic pitfalls. Errors may occur during variant detection, filtering, or interpretation in relation to patient's phenotype. Based on detailed clinical assessment suitable targeted and untargeted methods to identify pathogenic variants with context-dependent filtering and evaluation approaches will be discussed.
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Affiliation(s)
- Jan Fischer
- Institute for Clinical Genetics, University Hospital, TU Dresden, Dresden, Germany
| | - Nataliya Di Donato
- Institute for Clinical Genetics, University Hospital, TU Dresden, Dresden, Germany.
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9
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Rodgers J, Calvert S, Shoubridge C, McGaughran J. A novel ARX loss of function variant in female monozygotic twins is associated with chorea. Eur J Med Genet 2021; 64:104315. [PMID: 34419634 DOI: 10.1016/j.ejmg.2021.104315] [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: 11/07/2020] [Revised: 06/29/2021] [Accepted: 08/18/2021] [Indexed: 10/20/2022]
Abstract
Pathogenic variants in ARX lead to a variety of phenotypes with intellectual disability being a uniform feature. Other features can include severe epilepsy, spasticity, movement disorders, agenesis of the corpus callosum, lissencephaly, hydranencephaly and ambiguous genitalia in males. We present the first report of monozygotic female twins with a de novo ARX pathogenic variant (c.1406_1415del; p. Ala469Aspfs*20), predicted to result in a truncated ARX protein missing the important regulatory Aristaless domain. The twins presented with profound developmental delay and seizures, consistent with the known genotype-phenotype correlation. Twin 2's features were significantly more severe. She also developed chorea; the first time this movement disorder has been seen in an ARX variant other than an expansion of the first polyalanine tract. Differential X-chromosome inactivation was the most likely explanation for the differing severities but could not be conclusively proven.
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Affiliation(s)
- Jonathan Rodgers
- Genetic Health Queensland, Royal Brisbane and Women's Hospital, QLD, Australia; School of Medicine, The University of Queensland, Brisbane, QLD, Australia.
| | - Sophie Calvert
- Department of Neurosciences, Queensland Children's Hospital, Brisbane, QLD, Australia; School of Medicine, The University of Queensland, Brisbane, QLD, Australia
| | - Cheryl Shoubridge
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia; Robinson Research Institute, University of Adelaide, Adelaide, South Australia, Australia
| | - Julie McGaughran
- Genetic Health Queensland, Royal Brisbane and Women's Hospital, QLD, Australia; School of Medicine, The University of Queensland, Brisbane, QLD, Australia
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10
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Poeta L, Padula A, Lioi MB, van Bokhoven H, Miano MG. Analysis of a Set of KDM5C Regulatory Genes Mutated in Neurodevelopmental Disorders Identifies Temporal Coexpression Brain Signatures. Genes (Basel) 2021; 12:genes12071088. [PMID: 34356104 PMCID: PMC8305412 DOI: 10.3390/genes12071088] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 07/13/2021] [Accepted: 07/15/2021] [Indexed: 12/22/2022] Open
Abstract
Dysregulation of transcriptional pathways is observed in multiple forms of neurodevelopmental disorders (NDDs), such as intellectual disability (ID), epilepsy and autism spectrum disorder (ASD). We previously demonstrated that the NDD genes encoding lysine-specific demethylase 5C (KDM5C) and its transcriptional regulators Aristaless related-homeobox (ARX), PHD Finger Protein 8 (PHF8) and Zinc Finger Protein 711 (ZNF711) are functionally connected. Here, we show their relation to each other with respect to the expression levels in human and mouse datasets and in vivo mouse analysis indicating that the coexpression of these syntenic X-chromosomal genes is temporally regulated in brain areas and cellular sub-types. In co-immunoprecipitation assays, we found that the homeotic transcription factor ARX interacts with the histone demethylase PHF8, indicating that this transcriptional axis is highly intersected. Furthermore, the functional impact of pathogenic mutations of ARX, KDM5C, PHF8 and ZNF711 was tested in lymphoblastoid cell lines (LCLs) derived from children with varying levels of syndromic ID establishing the direct correlation between defects in the KDM5C-H3K4me3 pathway and ID severity. These findings reveal novel insights into epigenetic processes underpinning NDD pathogenesis and provide new avenues for assessing developmental timing and critical windows for potential treatments.
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Affiliation(s)
- Loredana Poeta
- Institute of Genetics and Biophysics Adriano Buzzati-Traverso, CNR, 80131 Naples, Italy;
- Department of Science, University of Basilicata, 85100 Potenza, Italy;
- Correspondence: (L.P.); (M.G.M.); Tel.: +39-(0)-816132261/445 (M.G.M.)
| | - Agnese Padula
- Institute of Genetics and Biophysics Adriano Buzzati-Traverso, CNR, 80131 Naples, Italy;
| | | | - Hans van Bokhoven
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboudumc, 6525 GA Nijmegen, The Netherlands;
| | - Maria Giuseppina Miano
- Institute of Genetics and Biophysics Adriano Buzzati-Traverso, CNR, 80131 Naples, Italy;
- Correspondence: (L.P.); (M.G.M.); Tel.: +39-(0)-816132261/445 (M.G.M.)
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11
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Scalia B, Venti V, Ciccia LM, Criscione R, Lo Bianco M, Sciuto L, Falsaperla R, Zanghì A, Praticò AD. Aristaless-Related Homeobox (ARX): Epilepsy Phenotypes beyond Lissencephaly and Brain Malformations. JOURNAL OF PEDIATRIC NEUROLOGY 2021. [DOI: 10.1055/s-0041-1727140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
AbstractThe Aristaless-related homeobox (ARX) transcription factor is involved in the development of GABAergic and cholinergic neurons in the forebrain. ARX mutations have been associated with a wide spectrum of neurodevelopmental disorders in humans and are responsible for both malformation (in particular lissencephaly) and nonmalformation complex phenotypes. The epilepsy phenotypes related to ARX mutations are West syndrome and X-linked infantile spasms, X-linked myoclonic epilepsy with spasticity and intellectual development and Ohtahara and early infantile epileptic encephalopathy syndrome, which are related in most of the cases to intellectual disability and are often drug resistant. In this article, we shortly reviewed current knowledge of the function of ARX with a particular attention on its consequences in the development of epilepsy during early childhood.
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Affiliation(s)
- Bruna Scalia
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Valeria Venti
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Lina M. Ciccia
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Roberta Criscione
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Manuela Lo Bianco
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Laura Sciuto
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Raffaele Falsaperla
- Unit of Pediatrics and Pediatric Emergency, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
- Neonatal Intensive Care unit and Neonatology, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
| | - Antonio Zanghì
- Department of Medical and Surgical Sciences and Advanced Technology “G.F. Ingrassia,” University of Catania, Catania, Italy
| | - Andrea D. Praticò
- Unit of Rare Diseases of the Nervous System in Childhood, Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, Catania, Italy
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12
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Benmakhlouf Y, Touraine R, Harzallah I, Zian Z, Ben Makhlouf K, Barakat A, Ghailani Nourouti N, Bennani Mechita M. Screening of the duplication 24 pb of ARX gene in Moroccan patients with X-linked Intellectual Disability. BMC Res Notes 2021; 14:110. [PMID: 33757564 PMCID: PMC7988900 DOI: 10.1186/s13104-021-05526-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 03/13/2021] [Indexed: 11/10/2022] Open
Abstract
OBJECTIVE Intellectual Disability (ID) represents a neuropsychiatric disorder, which its etiopathogenesis remains insufficiently understood. Mutations in the Aristaless Related Homeobox gene (ARX) have been identified to cause syndromic and nonsyndromic (NS-ID). The most recurrent mutation of this gene is a duplication of 24pb, c.428-451dup. Epidemiological and genetic studies about ID in the Moroccan population remain very scarce, and none study is carried out on the ARX gene. This work aimed to study c.428-451dup (24 bp) mutation in the exon 2 of the ARX gene in 118 males' Moroccan patients with milder NS-ID to evaluate if the gene screening is a good tool for identifying NS-ID. RESULTS Our mutational analysis did not show any dup(24pb) in our patients. This is because based on findings from previous studies that found ARX mutations in 70% of families with NS-ID, and in most cases, 1.5-6.1% of individuals with NS-ID have this duplication. Since 1/118 = 0.0084 (0.84%) is not much different from 1.5%, then it is reasonable that this could a sample size artifact. A complete screening of the entire ARX gene, including the five exons, should be fulfilled. Further investigations are required to confirm these results.
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Affiliation(s)
- Yousra Benmakhlouf
- Biomedical Genomics and Oncogenetics Research Laboratory, Faculty of Sciences and Techniques of Tangier, University Abdelmalek Essaadi, P.B.:416, Tangier, Morocco.
| | | | - Ines Harzallah
- Molecular Genetics Laboratory, CHU, Saint Etienne, France
| | - Zeineb Zian
- Biomedical Genomics and Oncogenetics Research Laboratory, Faculty of Sciences and Techniques of Tangier, University Abdelmalek Essaadi, P.B.:416, Tangier, Morocco
| | | | - Amina Barakat
- Biomedical Genomics and Oncogenetics Research Laboratory, Faculty of Sciences and Techniques of Tangier, University Abdelmalek Essaadi, P.B.:416, Tangier, Morocco
| | - Naima Ghailani Nourouti
- Biomedical Genomics and Oncogenetics Research Laboratory, Faculty of Sciences and Techniques of Tangier, University Abdelmalek Essaadi, P.B.:416, Tangier, Morocco
| | - Mohcine Bennani Mechita
- Biomedical Genomics and Oncogenetics Research Laboratory, Faculty of Sciences and Techniques of Tangier, University Abdelmalek Essaadi, P.B.:416, Tangier, Morocco
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13
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Mazen I, Mekkawy M, Kamel A, Essawi M, Hassan H, Abdel-Hamid M, Amr K, Soliman H, El-Ruby M, Torky A, El Gammal M, Elaidy A, Bashamboo A, McElreavey K. Advances in genomic diagnosis of a large cohort of Egyptian patients with disorders of sex development. Am J Med Genet A 2021; 185:1666-1677. [PMID: 33742552 DOI: 10.1002/ajmg.a.62129] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Revised: 01/28/2021] [Accepted: 01/30/2021] [Indexed: 12/15/2022]
Abstract
Disorders/differences of sex development (DSD) comprise a group of congenital disorders that affect the genitourinary tract and usually involve the endocrine and reproductive system. The aim of this work was to identify genetic variants responsible for disorders of human urogenital development in a cohort of Egyptian patients. This three-year study included 225 patients with various DSD forms, referred to the genetic DSD and endocrinology clinic, National Research Centre, Egypt. The patients underwent thorough clinical examination, hormonal and imaging studies, detailed cytogenetic and fluorescence in situ hybridization analysis, and molecular sequencing of genes known to commonly cause DSD including AR, SRD5A2, 17BHSD3, NR5A1, SRY, and WT1. Whole exome sequencing (WES) was carried out for 18 selected patients. The study revealed a high rate of sex chromosomal DSD (33%) with a wide array of cytogenetic abnormalities. Sanger sequencing identified pathogenic variants in 33.7% of 46,XY patients, while the detection rate of WES reached 66.7%. Our patients showed a different mutational profile compared with that reported in other populations with a predominance of heritable DSD causes. WES identified rare and novel pathogenic variants in NR5A1, WT1, HHAT, CYP19A1, AMH, AMHR2, and FANCA and in the X-linked genes ARX and KDM6A. In addition, digenic inheritance was observed in two of our patients and was suggested to be a cause of the phenotypic variability observed in DSD.
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Affiliation(s)
- Inas Mazen
- Department of Clinical Genetics, National Research Centre, Cairo, Egypt
| | - Mona Mekkawy
- Department of Human Cytogenetics, National Research Center, Cairo, Egypt
| | - Alaa Kamel
- Department of Human Cytogenetics, National Research Center, Cairo, Egypt
| | - Mona Essawi
- Department of Medical Molecular Genetics, National Research Centre, Cairo, Egypt
| | - Heba Hassan
- Department of Medical Molecular Genetics, National Research Centre, Cairo, Egypt
| | - Mohamed Abdel-Hamid
- Department of Medical Molecular Genetics, National Research Centre, Cairo, Egypt
| | - Khalda Amr
- Department of Medical Molecular Genetics, National Research Centre, Cairo, Egypt
| | - Hala Soliman
- Department of Medical Molecular Genetics, National Research Centre, Cairo, Egypt
| | - Mona El-Ruby
- Department of Clinical Genetics, National Research Centre, Cairo, Egypt
| | - Ahmed Torky
- Department of Clinical Genetics, National Research Centre, Cairo, Egypt
| | - Mona El Gammal
- Department of Clinical Genetics, National Research Centre, Cairo, Egypt
| | - Aya Elaidy
- Department of Clinical Genetics, National Research Centre, Cairo, Egypt
| | - Anu Bashamboo
- Developmental Genetics and Stem Cell Biology, Institut Pasteur, Paris, France
| | - Kenneth McElreavey
- Developmental Genetics and Stem Cell Biology, Institut Pasteur, Paris, France
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14
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Takeshita Y, Ohto T, Enokizono T, Tanaka M, Suzuki H, Fukushima H, Uehara T, Takenouchi T, Kosaki K, Takada H. Novel ARX mutation identified in infantile spasm syndrome patient. Hum Genome Var 2020; 7:9. [PMID: 32257294 PMCID: PMC7109071 DOI: 10.1038/s41439-020-0094-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Revised: 02/25/2020] [Accepted: 02/26/2020] [Indexed: 11/08/2022] Open
Abstract
We report a 7-year-old boy with infantile spasms caused by a novel mutation in the Aristaless-related homeobox (ARX) gene. He showed infantile spasms and hypsarrhythmia on electroencephalogram from early infancy. Brain MRI did not reveal severe malformation of the brain except mild hypoplasia of the corpus callosum. Two-fold adrenocorticotropic hormone (ACTH) therapy failed to control the seizures, and ketogenic diet therapy and multi-antiepileptic drug therapy were required as he showed intractable daily tonic-clonic seizures. Exome sequencing identified a hemizygous mutation in the ARX gene, NG_008281.1(ARX_v001):c.1448 + 1 G > A, chrX: 25025227 C > T (GRCh37). To our knowledge, this mutation has not been reported previously.
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Affiliation(s)
- Yohei Takeshita
- Department of Pediatrics, Ibaraki Seinan Medical Center Hospital, Sakai-machi, Japan
| | - Tatsuyuki Ohto
- Department of Pediatrics, University of Tsukuba Hospital, Tsukuba, Japan
- Department of Child Health, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Takashi Enokizono
- Department of Pediatrics, University of Tsukuba Hospital, Tsukuba, Japan
| | - Mai Tanaka
- Department of Pediatrics, University of Tsukuba Hospital, Tsukuba, Japan
| | - Hisato Suzuki
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Hiroko Fukushima
- Department of Pediatrics, University of Tsukuba Hospital, Tsukuba, Japan
- Department of Child Health, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Tomoko Uehara
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Toshiki Takenouchi
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Kenjiro Kosaki
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Hidetoshi Takada
- Department of Pediatrics, University of Tsukuba Hospital, Tsukuba, Japan
- Department of Child Health, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
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15
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Siehr MS, Massey CA, Noebels JL. Arx expansion mutation perturbs cortical development by augmenting apoptosis without activating innate immunity in a mouse model of X-linked infantile spasms syndrome. Dis Model Mech 2020; 13:dmm042515. [PMID: 32033960 PMCID: PMC7132796 DOI: 10.1242/dmm.042515] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 01/27/2020] [Indexed: 01/12/2023] Open
Abstract
X-linked infantile spasms syndrome (ISSX) is a clinically devastating developmental epileptic encephalopathy with life-long impact. Arx(GCG)10+7 , a mouse model of the most common triplet-repeat expansion mutation of ARX, exhibits neonatal spasms, electrographic phenotypes and abnormal migration of GABAergic interneuron subtypes. Neonatal presymptomatic treatment with 17β-estradiol (E2) in Arx(GCG)10+7 reduces spasms and modifies progression of epilepsy. Cortical pathology during this period, a crucial point for clinical intervention in ISSX, has largely been unexplored, and the pathogenic cellular defects that are targeted by early interventions are unknown. In the first postnatal week, we identified a transient wave of elevated apoptosis in Arx(GCG)10+7 mouse cortex that is non-Arx cell autonomous, since mutant Arx-immunoreactive (Arx+) cells are not preferentially impacted by cell death. NeuN+ (also known as Rbfox3) survival was also not impacted, suggesting a vulnerable subpopulation in the immature Arx(GCG)10+7 cortex. Inflammatory processes during this period might explain this transient elevation in apoptosis; however, transcriptomic and immunohistochemical profiling of several markers of inflammation revealed no innate immune activation in Arx(GCG)10+7 cortex. Neither neonatal E2 hormone therapy, nor ACTH(1-24), the frontline clinical therapy for ISSX, diminished the augmented apoptosis in Arx(GCG)10+7 , but both rescued neocortical Arx+ cell density. Since early E2 treatment effectively prevents seizures in this model, enhanced apoptosis does not solely account for the seizure phenotype, but may contribute to other aberrant brain function in ISSX. However, since both hormone therapies, E2 and ACTH(1-24), elevate the density of cortical Arx+-interneurons, their early therapeutic role in other neurological disorders hallmarked by interneuronopathy should be explored.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Meagan S Siehr
- Developmental Neurogenetics Laboratory, Department of Neurology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
- Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Cory A Massey
- Developmental Neurogenetics Laboratory, Department of Neurology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Jeffrey L Noebels
- Developmental Neurogenetics Laboratory, Department of Neurology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
- Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
- Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
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16
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Frints SGM, Hennig F, Colombo R, Jacquemont S, Terhal P, Zimmerman HH, Hunt D, Mendelsohn BA, Kordaß U, Webster R, Sinnema M, Abdul-Rahman O, Suckow V, Fernández-Jaén A, van Roozendaal K, Stevens SJC, Macville MVE, Al-Nasiry S, van Gassen K, Utzig N, Koudijs SM, McGregor L, Maas SM, Baralle D, Dixit A, Wieacker P, Lee M, Lee AS, Engle EC, Houge G, Gradek GA, Douglas AGL, Longman C, Joss S, Velasco D, Hennekam RC, Hirata H, Kalscheuer VM. Deleterious de novo variants of X-linked ZC4H2 in females cause a variable phenotype with neurogenic arthrogryposis multiplex congenita. Hum Mutat 2019; 40:2270-2285. [PMID: 31206972 DOI: 10.1002/humu.23841] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Revised: 05/30/2019] [Accepted: 06/10/2019] [Indexed: 12/22/2022]
Abstract
Pathogenic variants in the X-linked gene ZC4H2, which encodes a zinc-finger protein, cause an infrequently described syndromic form of arthrogryposis multiplex congenita (AMC) with central and peripheral nervous system involvement. We present genetic and detailed phenotypic information on 23 newly identified families and simplex cases that include 19 affected females from 18 families and 14 affected males from nine families. Of note, the 15 females with deleterious de novo ZC4H2 variants presented with phenotypes ranging from mild to severe, and their clinical features overlapped with those seen in affected males. By contrast, of the nine carrier females with inherited ZC4H2 missense variants that were deleterious in affected male relatives, four were symptomatic. We also compared clinical phenotypes with previously published cases of both sexes and provide an overview on 48 males and 57 females from 42 families. The spectrum of ZC4H2 defects comprises novel and recurrent mostly inherited missense variants in affected males, and de novo splicing, frameshift, nonsense, and partial ZC4H2 deletions in affected females. Pathogenicity of two newly identified missense variants was further supported by studies in zebrafish. We propose ZC4H2 as a good candidate for early genetic testing of males and females with a clinical suspicion of fetal hypo-/akinesia and/or (neurogenic) AMC.
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Affiliation(s)
- Suzanna G M Frints
- Department of Clinical Genetics, Maastricht University Medical Center+, azM, Maastricht, The Netherlands.,Department of Genetics and Cell Biology, Faculty of Health Medicine Life Sciences, Maastricht University Medical Center+, Maastricht University, Maastricht, The Netherlands
| | - Friederike Hennig
- Research Group Development and Disease, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Roberto Colombo
- Catholic University of the Sacred Heart, Rome, Italy.,Center for the Study of Rare Inherited Diseases (CeSMER), Niguarda Ca' Granda Metropolitan Hospital, Milan, Italy
| | | | - Paulien Terhal
- Laboratories, Pharmacy and Biomedical Genetics Division, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Holly H Zimmerman
- Department of Pediatrics, Division of Medical Genetics, University of Mississippi Medical Center, Jackson, Mississippi
| | - David Hunt
- Wessex Clinical Genetics Service, University Hospital Southampton NHS Foundation Trust, Southampton, UK
| | - Bryce A Mendelsohn
- Division of Genetics, Department of Pediatrics, University of California, San Francisco, California
| | - Ulrike Kordaß
- MVZ für Humangenetik und Molekularpathologie GmbH, Greifswald, Germany
| | - Richard Webster
- The Department of Neurology and Neurosurgery, The Children's Hospital at Westmead, Westmead, NSW, Australia
| | - Margje Sinnema
- Department of Clinical Genetics, Maastricht University Medical Center+, azM, Maastricht, The Netherlands.,Department of Genetics and Cell Biology, Faculty of Health Medicine Life Sciences, Maastricht University Medical Center+, Maastricht University, Maastricht, The Netherlands
| | - Omar Abdul-Rahman
- Munroe-Meyer Institute for Genetics & Rehabilitation, University of Nebraska Medical Center, Omaha, Nebraska
| | - Vanessa Suckow
- Research Group Development and Disease, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | | | - Kees van Roozendaal
- Department of Clinical Genetics, Maastricht University Medical Center+, azM, Maastricht, The Netherlands
| | - Servi J C Stevens
- Department of Clinical Genetics, Maastricht University Medical Center+, azM, Maastricht, The Netherlands.,Department of Genetics and Cell Biology, Faculty of Health Medicine Life Sciences, Maastricht University Medical Center+, Maastricht University, Maastricht, The Netherlands
| | - Merryn V E Macville
- Department of Clinical Genetics, Maastricht University Medical Center+, azM, Maastricht, The Netherlands.,Department of Genetics and Cell Biology, Faculty of Health Medicine Life Sciences, Maastricht University Medical Center+, Maastricht University, Maastricht, The Netherlands
| | - Salwan Al-Nasiry
- Department of Obstetrics and Gynecology, Prenatal Diagnostics & Therapy, Maastricht University Medical Center+, Maastricht, The Netherlands
| | - Koen van Gassen
- Laboratories, Pharmacy and Biomedical Genetics Division, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Norbert Utzig
- Klinik für Kinder- und Jugendmedizin, Universitätsmedizin Greifswald, Greifswald, Germany
| | - Suzanne M Koudijs
- Department of Neurology, Maastricht University Medical Center+, Maastricht, The Netherlands
| | - Lesley McGregor
- SA Clinical Genetics Service, Women's and Children's Hospital, North Adelaide, SA, Australia
| | - Saskia M Maas
- Department of Clinical Genetics, Amsterdam UMC, Amsterdam, The Netherlands
| | - Diana Baralle
- Wessex Clinical Genetics Service, University Hospital Southampton NHS Foundation Trust, Southampton, UK.,Faculty of Medicine, University of Southampton, Southampton, UK
| | - Abhijit Dixit
- City Hospital Campus, Nottingham University Hospitals NHS Trust, Nottingham, UK
| | - Peter Wieacker
- Institute of Human Genetics, Westfälische Wilhelms Universität Münster, Münster, Germany
| | - Marcus Lee
- Department of Pediatrics, Division of Pediatric Neurology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Arthur S Lee
- Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts.,Broad Institute of MIT and Harvard, Cambridge, Massachusetts
| | - Elizabeth C Engle
- Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts.,Broad Institute of MIT and Harvard, Cambridge, Massachusetts.,Department of Ophthalmology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts.,Howard Hughes Medical Institute, Chevy Chase, Maryland
| | - Gunnar Houge
- Department of Medical Genetics, Haukeland University Hospital, Bergen, Norway
| | - Gyri A Gradek
- Department of Medical Genetics, Haukeland University Hospital, Bergen, Norway
| | - Andrew G L Douglas
- Wessex Clinical Genetics Service, University Hospital Southampton NHS Foundation Trust, Southampton, UK.,Human Development and Health, Faculty of Medicine, University of Southampton, UK
| | - Cheryl Longman
- West of Scotland Regional Genetic Centre, Queen Elizabeth University Hospital, Glasgow, Scotland, UK
| | - Shelagh Joss
- West of Scotland Regional Genetic Centre, Queen Elizabeth University Hospital, Glasgow, Scotland, UK
| | - Danita Velasco
- Department of Pediatrics, Munroe-Meyer Institute for Genetics & Rehabilitation, University of Nebraska Medical Center, Omaha, Nebraska
| | - Raoul C Hennekam
- Department of Pediatrics, Amsterdam UMC, Amsterdam, The Netherlands
| | - Hiromi Hirata
- Department of Chemistry and Biological Science, College of Science and Engineering, Aoyama Gakuin University, Sagamihara, Japan
| | - Vera M Kalscheuer
- Research Group Development and Disease, Max Planck Institute for Molecular Genetics, Berlin, Germany
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17
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Represa A. Why Malformations of Cortical Development Cause Epilepsy. Front Neurosci 2019; 13:250. [PMID: 30983952 PMCID: PMC6450262 DOI: 10.3389/fnins.2019.00250] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 03/04/2019] [Indexed: 12/13/2022] Open
Abstract
Malformations of cortical development (MCDs), a complex family of rare disorders, result from alterations of one or combined developmental steps, including progenitors proliferation, neuronal migration and differentiation. They are an important cause of childhood epilepsy and frequently associate cognitive deficits and behavioral alterations. Though the physiopathological mechanisms of epilepsy in MCD patients remain poorly elucidated, research during the past decade highlighted the contribution of some factors that will be reviewed in this paper and that include: (i) the genes that caused the malformation, that can be responsible for a significant reduction of inhibitory cells (e.g., ARX gene) or be inducing cell-autonomous epileptogenic changes in affected neurons (e.g., mutations on the mTOR pathway); (ii) the alteration of cortical networks development induced by the malformation that will also involve adjacent or distal cortical areas apparently sane so that the epileptogenic focus might be more extended that the malformation or even localized at distance from it; (iii) the normal developmental processes that would influence and determine the onset of epilepsy in MCD patients, particularly precocious in most of the cases.
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Affiliation(s)
- Alfonso Represa
- INSERM, Institut de Neurobiologie de la Méditerranée, Aix-Marseille University, Marseille, France
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18
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Wu Y, Zhang H, Liu X, Shi Z, Li H, Wang Z, Jie X, Huang S, Zhang F, Li J, Zhang K, Gao X. Mutations of ARX and non-syndromic intellectual disability in Chinese population. Genes Genomics 2018; 41:125-131. [PMID: 30255221 DOI: 10.1007/s13258-018-0745-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 09/15/2018] [Indexed: 02/08/2023]
Abstract
Mutations of Aristaless-related homeobox (ARX) gene were looked as the third cause of non-syndromic intellectual disability (NSID), while the boundary between true disease-causing mutations and non-disease-causing variants within this gene remains elusive. To investigate the relationship between ARX mutations and NSID, a panel comprising six reported causal mutations of the ARX was detected in 369 sporadic NSID patients and 550 random participants in Chinese. Two mutations, c.428_451 dup and p.G286S, may be disease-causing mutations for NSID, while p.Q163R and p.P353L showed a great predictive value in female NSID diagnosis with significant associations (X2 = 19.60, p = 9.54e-6 for p.Q163R; X2 = 25.70, p = 4.00e-07 for p.P353L), carriers of these mutations had an increased risk of NSID of more than fourfold. Detection of this panel also predicted significant associations between genetic variants of the ARX gene and NSID (p = 3.73e-4). The present study emphasized the higher genetic burden of the ARX gene on NSID in the Chinese population, molecular analysis of this gene should be considered for patients presenting NSID of unknown etiology.
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Affiliation(s)
- Yufei Wu
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), Institute of Population and Health, Northwest University, Xi'an, 710069, China
| | - Huan Zhang
- The 2nd Affiliated Hospital, Xi'an Jiaotong University, Xi'an, 710004, China
| | - Xiaofen Liu
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), Institute of Population and Health, Northwest University, Xi'an, 710069, China
| | - Zhangyan Shi
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), Institute of Population and Health, Northwest University, Xi'an, 710069, China
| | - Hongling Li
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), Institute of Population and Health, Northwest University, Xi'an, 710069, China
| | - Zhibin Wang
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), Institute of Population and Health, Northwest University, Xi'an, 710069, China
| | - Xiaoyong Jie
- Xi'an Cangning Psychiatric Hospital, Xi'an, 710114, China
| | - Shaoping Huang
- The 2nd Affiliated Hospital, Xi'an Jiaotong University, Xi'an, 710004, China
| | - Fuchang Zhang
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), Institute of Population and Health, Northwest University, Xi'an, 710069, China.,College of Public Management, Institute of Application Psychology, Northwest University, Xi'an, 710127, China
| | - Junlin Li
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), Institute of Population and Health, Northwest University, Xi'an, 710069, China
| | - Kejin Zhang
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), Institute of Population and Health, Northwest University, Xi'an, 710069, China.
| | - Xiaocai Gao
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), Institute of Population and Health, Northwest University, Xi'an, 710069, China. .,College of Public Management, Institute of Application Psychology, Northwest University, Xi'an, 710127, China.
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19
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Basal ganglia involvement in ARX patients: The reason for ARX patients very specific grasping? NEUROIMAGE-CLINICAL 2018; 19:454-465. [PMID: 29984154 PMCID: PMC6029499 DOI: 10.1016/j.nicl.2018.04.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 03/05/2018] [Accepted: 04/01/2018] [Indexed: 01/15/2023]
Abstract
The ARX (Aristaless Related homeoboX) gene was identified in 2002 as responsible for XLAG syndrome, a lissencephaly characterized by an almost complete absence of cortical GABAergic interneurons, and for milder forms of X-linked Intellectual Disability (ID) without apparent brain abnormalities. The most frequent mutation found in the ARX gene, a duplication of 24 base pairs (c.429_452dup24) in exon 2, results in a recognizable syndrome in which patients present ID without primary motor impairment, but with a very specific upper limb distal motor apraxia associated with a pathognomonic hand-grip, described as developmental Limb Kinetic Apraxia (LKA). In this study, we first present ARX expression during human fetal brain development showing that it is strongly expressed in GABAergic neuronal progenitors during the second and third trimester of pregnancy. We show that although ARX expression strongly decreases towards the end of gestation, it is still present after birth in some neurons of the basal ganglia, thalamus and cerebral cortex, suggesting that ARX also plays a role in more mature neuron functioning. Then, using morphometric brain MRI in 13 ARX patients carrying c.429_452dup24 mutation and in 13 sex- and age-matched healthy controls, we show that ARX patients have a significantly decreased volume of several brain structures including the striatum (and more specifically the caudate nucleus), hippocampus and thalamus as well as decreased precentral gyrus cortical thickness. We observe a significant correlation between caudate nucleus volume reduction and motor impairment severity quantified by kinematic parameter of precision grip. As basal ganglia are known to regulate sensorimotor processing and are involved in the control of precision gripping, the combined decrease in cortical thickness of primary motor cortex and basal ganglia volume in ARX dup24 patients is very likely the anatomical substrate of this developmental form of LKA. c.429_452dup24 in ARX is responsible for ID with Limb Kinetic Apraxia. During human brain development, ARX is expressed in GABAergic neuronal progenitors. ARX patients have a significantly decreased caudate nucleus volume by MRI. This caudate nucleus volume reduction is correlated with motor impairment severity. These anatomic findings may explain this developmental form of Limb Kinetic Apraxia.
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Key Words
- ARX
- ARX, Aristaless-Related homeoboX gene (according to the genetic convention, ARX was written in italics when it refers to the gene, in plain-text characters when it refers to the protein, in capital letters when it refers to the human gene, and in lowercase when it refers to the mouse gene)
- CGE, caudal ganglionic eminence
- CP, cortical plate
- DS, down syndrome
- GE, ganglionic eminences
- Human brain development
- ICV, intracranial volume
- ID, Intellectual Disability
- IQ, intelligence quotient
- IZ, intermediate zone
- Intellectual disability
- Kinematic
- LGE, lateral ganglionic eminence
- LKA, Limb Kinetic Apraxia
- Limb Kinetic Apraxia
- MGE, medial ganglionic eminence
- MRI, magnetic resonance imaging
- MZ, marginal zone
- Morphometric MRI
- ROI, region of interest
- SGL, subpial granular layer
- SVZ, subventricular zone
- VZ, ventricular zone
- WG, weeks of gestation
- XLAG, X-linked lissencephaly with abnormal genitalia
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20
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Genetics and mechanisms leading to human cortical malformations. Semin Cell Dev Biol 2018; 76:33-75. [DOI: 10.1016/j.semcdb.2017.09.031] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 09/21/2017] [Accepted: 09/21/2017] [Indexed: 02/06/2023]
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21
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Abstract
Infantile spasms are a devastating epileptic encephalopathy characterized by early life spasms and later seizures. Clinical outcomes of infantile spasms are poor and therapeutic options are limited with significant adverse effects. Therefore, new strategies to treat infantile spasms are of the utmost importance. Animals models of infantile spasms are a critical component of developing new therapies. Here, we review current chronic animal models of infantile spasms and consider future advances that may help improve patient care, as well as our scientific understanding of this debilitating disease.
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Abstract
The tragedy of epilepsy emerges from the combination of its high prevalence, impact upon sufferers and their families, and unpredictability. Childhood epilepsies are frequently severe, presenting in infancy with pharmaco-resistant seizures; are often accompanied by debilitating neuropsychiatric and systemic comorbidities; and carry a grave risk of mortality. Here, we review the most current basic science and translational research findings on several of the most catastrophic forms of pediatric epilepsy. We focus largely on genetic epilepsies and the research that is discovering the mechanisms linking disease genes to epilepsy syndromes. We also describe the strides made toward developing novel pharmacological and interventional treatment strategies to treat these disorders. The research reviewed provides hope for a complete understanding of, and eventual cure for, these childhood epilepsy syndromes.
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Affiliation(s)
- MacKenzie A Howard
- Center for Learning and Memory and Department of Neuroscience, University of Texas at Austin, Texas, 78712;
| | - Scott C Baraban
- Epilepsy Research Laboratory in the Department of Neurological Surgery, Weill Institute for Neurosciences, University of California, San Francisco, California 94143;
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23
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Abstract
X-linked cerebellar ataxias (XLCA) are an expanding group of genetically heterogeneous and clinically variable conditions characterized by cerebellar dysgenesis (hypoplasia, atrophy, or dysplasia) caused by gene mutations or genomic imbalances on the X chromosome. The neurologic features of XLCA include hypotonia, developmental delay, intellectual disability, ataxia, and other cerebellar signs. Normal cognitive development has also been reported. Cerebellar defects may be isolated or associated with other brain malformations or extraneurologic involvement. More than 20 genes on the X chromosome, mainly encoding for proteins involved in brain development and synaptic function that have been constantly or occasionally associated with a pathologic cerebellar phenotype, and several families with X-linked inheritance have been reported. Given the excess of males with ataxia, this group of conditions is probably underestimated and families of patients with neuroradiologic and clinical evidence of a cerebellar disorder should be counseled for high risk of X-linked inheritance.
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Affiliation(s)
- Ginevra Zanni
- Unit of Neuromuscular and Neurodegenerative Disorders, Bambino Gesu' Children's Research Hospital, Rome, Italy.
| | - Enrico Bertini
- Unit of Neuromuscular and Neurodegenerative Disorders, Bambino Gesu' Children's Research Hospital, Rome, Italy
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24
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Duan H, Jiang K, Wei D, Zhang L, Cheng D, Lv M, Xu Y, He A. Identification of epigenetically altered genes and potential gene targets in melanoma using bioinformatic methods. Onco Targets Ther 2017; 11:9-15. [PMID: 29302192 PMCID: PMC5741985 DOI: 10.2147/ott.s146663] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
This study aimed to analyze epigenetically and genetically altered genes in melanoma to get a better understanding of the molecular circuitry of melanoma and identify potential gene targets for the treatment of melanoma. The microarray data of GSE31879, including mRNA expression profiles (seven melanoma and four melanocyte samples) and DNA methylation profiles (seven melanoma and five melanocyte samples), were downloaded from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) and differentially methylated positions (DMPs) were screened using the linear models for microarray data (limma) package in melanoma compared with melanocyte samples. Gene ontology (GO) and pathway enrichment analysis of the DEGs were carried out using the Database for Annotation, Visualization, and Integrated Discovery. Moreover, differentially methylated genes (DMGs) were identified, and a transcriptional regulatory network was constructed using the University of California Santa Cruz genome browser database. A total of 1,215 DEGs (199 upregulated and 1,016 downregulated) and 14,094 DMPs (10,450 upregulated and 3,644 downregulated) were identified in melanoma compared with melanocyte samples. Additionally, the upregulated and downregulated DEGs were significantly associated with different GO terms and pathways, such as pigment cell differentiation, biosynthesis, and metabolism. Furthermore, the transcriptional regulatory network showed that DMGs such as Aristaless-related homeobox (ARX), damage-specific DNA binding protein 2 (DDB2), and myelin basic protein (MBP) had higher node degrees. Our results showed that several methylated genes (ARX, DDB2, and MBP) may be involved in melanoma progression.
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Affiliation(s)
- Honghao Duan
- Department of Hand Surgery, Honghui Hospital, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, People's Republic of China
| | - Ke Jiang
- Department of Hand Surgery, Honghui Hospital, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, People's Republic of China
| | - Dengke Wei
- Department of Hand Surgery, Honghui Hospital, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, People's Republic of China
| | - Lijun Zhang
- Department of Hand Surgery, Honghui Hospital, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, People's Republic of China
| | - Deliang Cheng
- Department of Hand Surgery, Honghui Hospital, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, People's Republic of China
| | - Min Lv
- Department of Hand Surgery, Honghui Hospital, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, People's Republic of China
| | - Yuben Xu
- Department of Hand Surgery, Honghui Hospital, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, People's Republic of China
| | - Aimin He
- Department of Hand Surgery, Honghui Hospital, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, People's Republic of China
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25
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Intrinsic Disorder in Proteins with Pathogenic Repeat Expansions. Molecules 2017; 22:molecules22122027. [PMID: 29186753 PMCID: PMC6149999 DOI: 10.3390/molecules22122027] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 11/18/2017] [Accepted: 11/21/2017] [Indexed: 11/18/2022] Open
Abstract
Intrinsically disordered proteins and proteins with intrinsically disordered regions have been shown to be highly prevalent in disease. Furthermore, disease-causing expansions of the regions containing tandem amino acid repeats often push repetitive proteins towards formation of irreversible aggregates. In fact, in disease-relevant proteins, the increased repeat length often positively correlates with the increased aggregation efficiency and the increased disease severity and penetrance, being negatively correlated with the age of disease onset. The major categories of repeat extensions involved in disease include poly-glutamine and poly-alanine homorepeats, which are often times located in the intrinsically disordered regions, as well as repeats in non-coding regions of genes typically encoding proteins with ordered structures. Repeats in such non-coding regions of genes can be expressed at the mRNA level. Although they can affect the expression levels of encoded proteins, they are not translated as parts of an affected protein and have no effect on its structure. However, in some cases, the repetitive mRNAs can be translated in a non-canonical manner, generating highly repetitive peptides of different length and amino acid composition. The repeat extension-caused aggregation of a repetitive protein may represent a pivotal step for its transformation into a proteotoxic entity that can lead to pathology. The goals of this article are to systematically analyze molecular mechanisms of the proteinopathies caused by the poly-glutamine and poly-alanine homorepeat expansion, as well as by the polypeptides generated as a result of the microsatellite expansions in non-coding gene regions and to examine the related proteins. We also present results of the analysis of the prevalence and functional roles of intrinsic disorder in proteins associated with pathological repeat expansions.
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Jackson MR, Lee K, Mattiske T, Jaehne EJ, Ozturk E, Baune BT, O'Brien TJ, Jones N, Shoubridge C. Extensive phenotyping of two ARX polyalanine expansion mutation mouse models that span clinical spectrum of intellectual disability and epilepsy. Neurobiol Dis 2017; 105:245-256. [DOI: 10.1016/j.nbd.2017.05.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 04/30/2017] [Accepted: 05/29/2017] [Indexed: 11/17/2022] Open
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Kulkarni G, Ranade S. Molecular Analysis of Hotspot Regions ofARXandMECP2Genes in Intellectual Disability and Cornelia De Lange Syndrome. INT J HUM GENET 2017. [DOI: 10.1080/09723757.2017.1351119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Gayatri Kulkarni
- Department of Chemistry, Division of Biochemistry, Savitribai Phule Pune University, Pune 411 007, Maharashtra, India
| | - Suvidya Ranade
- Department of Chemistry, Division of Biochemistry, Savitribai Phule Pune University, Pune 411 007, Maharashtra, India
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Mattiske T, Lee K, Gecz J, Friocourt G, Shoubridge C. Embryonic forebrain transcriptome of mice with polyalanine expansion mutations in the ARX homeobox gene. Hum Mol Genet 2017; 25:5433-5443. [PMID: 27798109 DOI: 10.1093/hmg/ddw360] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 10/18/2016] [Indexed: 11/14/2022] Open
Abstract
The Aristaless-related homeobox (ARX) gene encodes a paired-type homeodomain transcription factor with critical roles in embryonic development. Mutations in ARX give rise to intellectual disability (ID), epilepsy and brain malformation syndromes. To capture the genetics and molecular disruptions that underpin the ARX-associated clinical phenotypes, we undertook a transcriptome wide RNASeq approach to analyse developing (12.5 dpc) telencephalon of mice modelling two recurrent polyalanine expansion mutations with different phenotypic severities in the ARX gene. Here we report 238 genes significantly deregulated (Log2FC > +/-1.1, P-value <0.05) when both mutations are compared to wild-type (WT) animals. When each mutation is considered separately, a greater number of genes were deregulated in the severe PA1 mice (825) than in the PA2 animals (78). Analysing genes deregulated in either or both mutant strains, we identified 12% as implicated in ID, epilepsy and autism (99/858), with ∼5% of them as putative or known direct targets of ARX transcriptional regulation. We propose a core pathway of transcription regulators, including Hdac4, involved in chromatin condensation and transcriptional repression, and one of its targets, the transcription factor Twist1, as potential drivers of the ID and infantile spasms in patients with ARX polyalanine expansion mutations. We predict that the subsequent disturbance to this pathway is a consequence of ARX protein reduction with a broader and more significant level of disruption in the PA1 in comparison to the PA2 mice. Identifying early triggers of ARX-associated phenotypes contributes to our understanding of particular clusters/pathways underpinning comorbid phenotypes that are shared by many neurodevelopmental disorders.
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Affiliation(s)
- Tessa Mattiske
- Department of Paediatrics, Adelaide Medical School.,Robinson Research Institute, University of Adelaide, SA, Australia
| | - Kristie Lee
- Department of Paediatrics, Adelaide Medical School.,Robinson Research Institute, University of Adelaide, SA, Australia
| | - Jozef Gecz
- Department of Paediatrics, Adelaide Medical School.,Robinson Research Institute, University of Adelaide, SA, Australia
| | - Gaelle Friocourt
- Inserm, UMR1078, Brest, France.,Brest University, Faculté de Médecine et des Sciences de la Santé, Sfr ScInBioS, Brest, France
| | - Cheryl Shoubridge
- Department of Paediatrics, Adelaide Medical School.,Robinson Research Institute, University of Adelaide, SA, Australia
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29
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Unexplained Early Infantile Epileptic Encephalopathy in Han Chinese Children: Next-Generation Sequencing and Phenotype Enriching. Sci Rep 2017; 7:46227. [PMID: 28387369 PMCID: PMC5384237 DOI: 10.1038/srep46227] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 03/13/2017] [Indexed: 11/08/2022] Open
Abstract
Early Infantile Epileptic Encephalopathy (EIEE) presents shortly after birth with frequent, severe seizures and progressive disturbance of cerebral function. This study was to investigate a cohort of Chinese children with unexplained EIEE, infants with previous genetic diagnoses, causative brain malformations, or inborn errors of metabolism were excluded. We used targeted next-generation sequencing to identify potential pathogenic variants of 308 genes in 68 Han Chinese patients with unexplained EIEE. A filter process was performed to prioritize rare variants of potential functional significance. In all cases where parental testing was accessible, Sanger sequencing confirmed the variants and determined the parental origin. In 15% of patients (n = 10/68), we identified nine de novo pathogenic variants, and one assumed de novo pathogenic variant in the following genes: CDKL5 (n = 2), STXBP1 (n = 2), SCN1A (n = 3), KCNQ2 (n = 2), SCN8A (n = 1), four of the variants are novel variants. In 4% patients (n = 3/68), we identified three likely pathogenic variants; two assumed de novo and one X-linked in the following genes: SCN1A (n = 2) and ARX (n = 1), two of these variants are novel. Variants were assumed de novo when parental testing was not available. Our findings were first reported in Han Chinese patients with unexplained EIEE, enriching the EIEE mutation spectrum bank.
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30
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Lintas C, Persico AM. Unraveling molecular pathways shared by Kabuki and Kabuki-like syndromes. Clin Genet 2017; 94:283-295. [PMID: 28139835 DOI: 10.1111/cge.12983] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 01/19/2017] [Indexed: 12/12/2022]
Abstract
Kabuki syndrome (KS) is a rare genetic syndrome characterized by a typical facial gestalt, variable degrees of intellectual disability, organ malformations, postnatal growth retardation and skeletal abnormalities. So far, KMT2D or KDM6A mutation has been identified as the main cause of KS, accounting for 56%-75% and 3%-8% of cases, respectively. Patients without mutations in 1 of the 2 causative KS genes are often referred to as affected by Kabuki-like syndrome. Overall, they represent approximately 30% of KS cases, pointing toward substantial genetic heterogeneity for this condition. Here, we review all currently available literature describing KS-like phenotypes (or phenocopies) associated with genetic variants located in loci different from KMT2D and KDM6A . We also report on a new KS phenocopy harboring a 5 Mb de novo deletion in chr10p11.22-11.21. An enrichment analysis aimed at identifying functional Gene Ontology classes shared by the 2 known KS causative genes and by new candidate genes currently associated with KS-like phenotypes primarily converges upon abnormal chromatin remodeling and transcriptional dysregulation as pivotal to the pathophysiology of KS phenotypic hallmarks. The identification of mutations in genes belonging to the same functional pathways of KMT2D and KDM6A can help design molecular screenings targeted to KS-like phenotypes.
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Affiliation(s)
- C Lintas
- Unit of Child and Adolescent NeuroPsychiatry, University Campus Bio-Medico, Rome, Italy.,Laboratory of Molecular Psychiatry and Neurogenetics, Department of Medicine, University Campus Bio-Medico, Rome, Italy
| | - A M Persico
- Unit of Child and Adolescent NeuroPsychiatry, "G. Martino" University Hospital, University of Messina, Messina, Italy.,Mafalda Luce Center for Pervasive Developmental Disorders, Milan, Italy
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31
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Bloomquist RF, Fowler TE, Sylvester JB, Miro RJ, Streelman JT. A compendium of developmental gene expression in Lake Malawi cichlid fishes. BMC DEVELOPMENTAL BIOLOGY 2017; 17:3. [PMID: 28158974 PMCID: PMC5291978 DOI: 10.1186/s12861-017-0146-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 01/26/2017] [Indexed: 12/24/2022]
Abstract
BACKGROUND Lake Malawi cichlids represent one of a growing number of vertebrate models used to uncover the genetic and developmental basis of trait diversity. Rapid evolutionary radiation has resulted in species that share similar genomes but differ markedly in phenotypes including brains and behavior, nuptial coloration and the craniofacial skeleton. Research has begun to identify the genes, as well as the molecular and developmental pathways that underlie trait divergence. RESULTS We assemble a compendium of gene expression for Lake Malawi cichlids, across pharyngula (the phylotypic stage) and larval stages of development, encompassing hundreds of gene transcripts. We chart patterns of expression in Bone morphogenetic protein (BMP), Fibroblast growth factor (FGF), Hedgehog (Hh), Notch and Wingless (Wnt) signaling pathways, as well as genes involved in neurogenesis, calcium and endocrine signaling, stem cell biology, and numerous homeobox (Hox) factors-in three planes using whole-mount in situ hybridization. Because of low sequence divergence across the Malawi cichlid assemblage, the probes we employ are broadly applicable in hundreds of species. We tabulate gene expression across general tissue domains, and highlight examples of unexpected expression patterns. CONCLUSIONS On the heels of recently published genomes, this compendium of developmental gene expression in Lake Malawi cichlids provides a valuable resource for those interested in the relationship between evolution and development.
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Affiliation(s)
- R F Bloomquist
- Georgia Institute of Technology, School of Biological Sciences and Institute for Bioengineering and Bioscience, Atlanta, GA, USA.,Medical College of Georgia, School of Dentistry, Augusta, GA, USA
| | - T E Fowler
- Georgia Institute of Technology, School of Biological Sciences and Institute for Bioengineering and Bioscience, Atlanta, GA, USA
| | - J B Sylvester
- Georgia Institute of Technology, School of Biological Sciences and Institute for Bioengineering and Bioscience, Atlanta, GA, USA
| | - R J Miro
- Georgia Institute of Technology, School of Biological Sciences and Institute for Bioengineering and Bioscience, Atlanta, GA, USA
| | - J T Streelman
- Georgia Institute of Technology, School of Biological Sciences and Institute for Bioengineering and Bioscience, Atlanta, GA, USA.
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32
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Lee J. Malformations of cortical development: genetic mechanisms and diagnostic approach. KOREAN JOURNAL OF PEDIATRICS 2017; 60:1-9. [PMID: 28203254 PMCID: PMC5309318 DOI: 10.3345/kjp.2017.60.1.1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 11/20/2015] [Accepted: 12/16/2015] [Indexed: 01/09/2023]
Abstract
Malformations of cortical development are rare congenital anomalies of the cerebral cortex, wherein patients present with intractable epilepsy and various degrees of developmental delay. Cases show a spectrum of anomalous cortical formations with diverse anatomic and morphological abnormalities, a variety of genetic causes, and different clinical presentations. Brain magnetic resonance imaging has been of great help in determining the exact morphologies of cortical malformations. The hypothetical mechanisms of malformation include interruptions during the formation of cerebral cortex in the form of viral infection, genetic causes, and vascular events. Recent remarkable developments in genetic analysis methods have improved our understanding of these pathological mechanisms. The present review will discuss normal cortical development, the current proposed malformation classifications, and the diagnostic approach for malformations of cortical development.
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Affiliation(s)
- Jeehun Lee
- Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
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33
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Chao HT, Davids M, Burke E, Pappas JG, Rosenfeld JA, McCarty AJ, Davis T, Wolfe L, Toro C, Tifft C, Xia F, Stong N, Johnson TK, Warr CG, Yamamoto S, Adams DR, Markello TC, Gahl WA, Bellen HJ, Wangler MF, Malicdan MCV, Adams DR, Adams CJ, Alejandro ME, Allard P, Ashley EA, Bacino CA, Balasubramanyam A, Barseghyan H, Beggs AH, Bellen HJ, Bernstein JA, Bick DP, Birch CL, Boone BE, Briere LC, Brown DM, Brush M, Burrage LC, Chao KR, Clark GD, Cogan JD, Cooper CM, Craigen WJ, Davids M, Dayal JG, Dell'Angelica EC, Dhar SU, Dipple KM, Donnell-Fink LA, Dorrani N, Dorset DC, Draper DD, Dries AM, Eckstein DJ, Emrick LT, Eng CM, Esteves C, Estwick T, Fisher PG, Frisby TS, Frost K, Gahl WA, Gartner V, Godfrey RA, Goheen M, Golas GA, Goldstein DB, Gordon M“GG, Gould SE, Gourdine JPF, Graham BH, Groden CA, Gropman AL, Hackbarth ME, Haendel M, Hamid R, Hanchard NA, Handley LH, Hardee I, Herzog MR, Holm IA, Howerton EM, Jacob HJ, Jain M, Jiang YH, Johnston JM, Jones AL, Koehler AE, Koeller DM, Kohane IS, Kohler JN, Krasnewich DM, Krieg EL, Krier JB, Kyle JE, Lalani SR, Latham L, Latour YL, Lau CC, Lazar J, Lee BH, Lee H, Lee PR, Levy SE, Levy DJ, Lewis RA, Liebendorder AP, Lincoln SA, Loomis CR, Loscalzo J, Maas RL, Macnamara EF, MacRae CA, Maduro VV, Malicdan MCV, Mamounas LA, Manolio TA, Markello TC, Mashid AS, Mazur P, McCarty AJ, McConkie-Rosell A, McCray AT, Metz TO, Might M, Moretti PM, Mulvihill JJ, Murphy JL, Muzny DM, Nehrebecky ME, Nelson SF, Newberry JS, Newman JH, Nicholas SK, Novacic D, Orange JS, Pallais JC, Palmer CG, Papp JC, Pena LD, Phillips JA, Posey JE, Postlethwait JH, Potocki L, Pusey BN, Ramoni RB, Rodan LH, Sadozai S, Schaffer KE, Schoch K, Schroeder MC, Scott DA, Sharma P, Shashi V, Silverman EK, Sinsheimer JS, Soldatos AG, Spillmann RC, Splinter K, Stoler JM, Stong N, Strong KA, Sullivan JA, Sweetser DA, Thomas SP, Tift CJ, Tolman NJ, Toro C, Tran AA, Valivullah ZM, Vilain E, Waggott DM, Wahl CE, Walley NM, Walsh CA, Wangler MF, Warburton M, Ward PA, Waters KM, Webb-Robertson BJM, Weech AA, Westerfield M, Wheeler MT, Wise AL, Worthe LA, Worthey EA, Yamamoto S, Yang Y, Yu G, Zornio PA. A Syndromic Neurodevelopmental Disorder Caused by De Novo Variants in EBF3. Am J Hum Genet 2017; 100:128-137. [PMID: 28017372 PMCID: PMC5223093 DOI: 10.1016/j.ajhg.2016.11.018] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 11/21/2016] [Indexed: 02/06/2023] Open
Abstract
Early B cell factor 3 (EBF3) is a member of the highly evolutionarily conserved Collier/Olf/EBF (COE) family of transcription factors. Prior studies on invertebrate and vertebrate animals have shown that EBF3 homologs are essential for survival and that loss-of-function mutations are associated with a range of nervous system developmental defects, including perturbation of neuronal development and migration. Interestingly, aristaless-related homeobox (ARX), a homeobox-containing transcription factor critical for the regulation of nervous system development, transcriptionally represses EBF3 expression. However, human neurodevelopmental disorders related to EBF3 have not been reported. Here, we describe three individuals who are affected by global developmental delay, intellectual disability, and expressive speech disorder and carry de novo variants in EBF3. Associated features seen in these individuals include congenital hypotonia, structural CNS malformations, ataxia, and genitourinary abnormalities. The de novo variants affect a single conserved residue in a zinc finger motif crucial for DNA binding and are deleterious in a fly model. Our findings indicate that mutations in EBF3 cause a genetic neurodevelopmental syndrome and suggest that loss of EBF3 function might mediate a subset of neurologic phenotypes shared by ARX-related disorders, including intellectual disability, abnormal genitalia, and structural CNS malformations.
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Paděrová J, Holubová A, Simandlová M, Puchmajerová A, Vlčková M, Malíková M, Pourová R, Vejvalková S, Havlovicová M, Šenkeříková M, Ptáková N, Drábová J, Geryk J, Maver A, Křepelová A, Macek M. Molecular genetic analysis in 14 Czech Kabuki syndrome patients is confirming the utility of phenotypic scoring. Clin Genet 2016; 90:230-7. [DOI: 10.1111/cge.12754] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Revised: 01/30/2016] [Accepted: 02/01/2016] [Indexed: 01/17/2023]
Affiliation(s)
- J. Paděrová
- Department of Biology and Medical Genetics; Charles University Prague-2 Faculty of Medicine and University Hospital Motol; Prague Czech Republic
| | - A. Holubová
- Department of Biology and Medical Genetics; Charles University Prague-2 Faculty of Medicine and University Hospital Motol; Prague Czech Republic
| | - M. Simandlová
- Department of Biology and Medical Genetics; Charles University Prague-2 Faculty of Medicine and University Hospital Motol; Prague Czech Republic
| | - A. Puchmajerová
- Department of Biology and Medical Genetics; Charles University Prague-2 Faculty of Medicine and University Hospital Motol; Prague Czech Republic
| | - M. Vlčková
- Department of Biology and Medical Genetics; Charles University Prague-2 Faculty of Medicine and University Hospital Motol; Prague Czech Republic
| | - M. Malíková
- Department of Biology and Medical Genetics; Charles University Prague-2 Faculty of Medicine and University Hospital Motol; Prague Czech Republic
| | - R. Pourová
- Department of Biology and Medical Genetics; Charles University Prague-2 Faculty of Medicine and University Hospital Motol; Prague Czech Republic
| | - S. Vejvalková
- Department of Biology and Medical Genetics; Charles University Prague-2 Faculty of Medicine and University Hospital Motol; Prague Czech Republic
| | - M. Havlovicová
- Department of Biology and Medical Genetics; Charles University Prague-2 Faculty of Medicine and University Hospital Motol; Prague Czech Republic
| | - M. Šenkeříková
- Department of Medical Genetics; Charles University Prague-Faculty of Medicine and University Hospital Hradec Králové; Hradec Králové Czech Republic
| | - N. Ptáková
- Department of Biology and Medical Genetics; Charles University Prague-2 Faculty of Medicine and University Hospital Motol; Prague Czech Republic
| | - J. Drábová
- Department of Biology and Medical Genetics; Charles University Prague-2 Faculty of Medicine and University Hospital Motol; Prague Czech Republic
| | - J. Geryk
- Department of Biology and Medical Genetics; Charles University Prague-2 Faculty of Medicine and University Hospital Motol; Prague Czech Republic
| | - A. Maver
- Department of Obstetrics & Gynecology, Centre for Mendelian Genomics, Clinical Institute of Medical Genetics; University Medical Centre Ljubljana; Ljubljana Slovenia
| | - A. Křepelová
- Department of Biology and Medical Genetics; Charles University Prague-2 Faculty of Medicine and University Hospital Motol; Prague Czech Republic
| | - M. Macek
- Department of Biology and Medical Genetics; Charles University Prague-2 Faculty of Medicine and University Hospital Motol; Prague Czech Republic
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A Novel Analog Reasoning Paradigm: New Insights in Intellectually Disabled Patients. PLoS One 2016; 11:e0149717. [PMID: 26918704 PMCID: PMC4771701 DOI: 10.1371/journal.pone.0149717] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 02/04/2016] [Indexed: 12/05/2022] Open
Abstract
Background Intellectual Disability (ID) is characterized by deficits in intellectual functions such as reasoning, problem-solving, planning, abstract thinking, judgment, and learning. As new avenues are emerging for treatment of genetically determined ID (such as Down’s syndrome or Fragile X syndrome), it is necessary to identify objective reliable and sensitive outcome measures for use in clinical trials. Objective We developed a novel visual analogical reasoning paradigm, inspired by the Progressive Raven’s Matrices, but appropriate for Intellectually Disabled patients. This new paradigm assesses reasoning and inhibition abilities in ID patients. Methods We performed behavioural analyses for this task (with a reaction time and error rate analysis, Study 1) in 96 healthy controls (adults and typically developed children older than 4) and 41 genetically determined ID patients (Fragile X syndrome, Down syndrome and ARX mutated patients). In order to establish and quantify the cognitive strategies used to solve the task, we also performed an eye-tracking analysis (Study 2). Results Down syndrome, ARX and Fragile X patients were significantly slower and made significantly more errors than chronological age-matched healthy controls. The effect of inhibition on error rate was greater than the matrix complexity effect in ID patients, opposite to findings in adult healthy controls. Interestingly, ID patients were more impaired by inhibition than mental age-matched healthy controls, but not by the matrix complexity. Eye-tracking analysis made it possible to identify the strategy used by the participants to solve the task. Adult healthy controls used a matrix-based strategy, whereas ID patients used a response-based strategy. Furthermore, etiologic-specific reasoning differences were evidenced between ID patients groups. Conclusion We suggest that this paradigm, appropriate for ID patients and developmental populations as well as adult healthy controls, provides an objective and quantitative assessment of visual analogical reasoning and cognitive inhibition, enabling testing for the effect of pharmacological or behavioural intervention in these specific populations.
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Copy number variants in patients with intellectual disability affect the regulation of ARX transcription factor gene. Hum Genet 2015; 134:1163-82. [PMID: 26337422 DOI: 10.1007/s00439-015-1594-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 08/16/2015] [Indexed: 10/23/2022]
Abstract
Protein-coding mutations in the transcription factor-encoding gene ARX cause various forms of intellectual disability (ID) and epilepsy. In contrast, variations in surrounding non-coding sequences are correlated with milder forms of non-syndromic ID and autism and had suggested the importance of ARX gene regulation in the etiology of these disorders. We compile data on several novel and some already identified patients with or without ID that carry duplications of ARX genomic region and consider likely genetic mechanisms underlying the neurodevelopmental defects. We establish the long-range regulatory domain of ARX and identify its brain region-specific autoregulation. We conclude that neurodevelopmental disturbances in the patients may not simply arise from increased dosage due to ARX duplication. This is further exemplified by a small duplication involving a non-functional ARX copy, but with duplicated enhancers. ARX enhancers are located within a 504-kb region and regulate expression specifically in the forebrain in developing and adult zebrafish. Transgenic enhancer-reporter lines were used as in vivo tools to delineate a brain region-specific negative and positive autoregulation of ARX. We find autorepression of ARX in the telencephalon and autoactivation in the ventral thalamus. Fluorescently labeled brain regions in the transgenic lines facilitated the identification of neuronal outgrowth and pathfinding disturbances in the ventral thalamus and telencephalon that occur when arxa dosage is diminished. In summary, we have established a model for how breakpoints in long-range gene regulation alter the expression levels of a target gene brain region-specifically, and how this can cause subtle neuronal phenotypes relating to the etiology of associated neuropsychiatric disease.
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Moey C, Topper S, Karn M, Johnson AK, Das S, Vidaurre J, Shoubridge C. Reinitiation of mRNA translation in a patient with X-linked infantile spasms with a protein-truncating variant in ARX. Eur J Hum Genet 2015; 24:681-9. [PMID: 26306640 DOI: 10.1038/ejhg.2015.176] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 06/30/2015] [Accepted: 07/03/2015] [Indexed: 12/30/2022] Open
Abstract
Mutations in the Aristaless-related homeobox gene (ARX) lead to a range of X-linked intellectual disability phenotypes, with truncating variants generally resulting in severe X-linked lissencephaly with ambiguous genitalia (XLAG), and polyalanine expansions and missense variants resulting in infantile spasms. We report two male patients with early-onset infantile spasms in whom a novel c.34G>T (p.(E12*)) variant was identified in the ARX gene. A similar variant c.81C>G (p.(Y27*)), has previously been described in two affected cousins with early-onset infantile spasms, leading to reinitiation of ARX mRNA translation resulting in an N-terminal truncated protein. We show that the novel c.34G>T (p.(E12*)) variant also reinitiated mRNA translation at the next AUG codon (c.121-123 (p.M41)), producing the same N-terminally truncated protein. The production of both of these truncated proteins was demonstrated to be at markedly reduced levels using in vitro cell assays. Using luciferase reporter assays, we demonstrate that transcriptional repression capacity of ARX was diminished by both the loss of the N-terminal corepressor octapeptide domain, as a consequence of truncation, and the marked reduction in mutant protein expression. Our study indicates that premature termination mutations very early in ARX lead to reinitiation of translation to produce N-terminally truncated protein at markedly reduced levels of expression. We conclude that even low levels of N-terminally truncated ARX is sufficient to improve the patient's phenotype compared with the severe phenotype of XLAG that includes malformations of the brain and genitalia normally seen in complete loss-of-function mutations in ARX.
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Affiliation(s)
- Ching Moey
- Department of Paediatrics, School of Peadiatrics and Reproductive Health, University of Adelaide, Adelaide, SA, Australia.,Robinson Research Institute, Faculty of Health Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Scott Topper
- Department of Human Genetics, University of Chicago, Chicago, IL, USA
| | - Mary Karn
- Nationwide Children's Hospital, Columbus, OH, USA
| | | | - Soma Das
- Department of Human Genetics, University of Chicago, Chicago, IL, USA
| | - Jorge Vidaurre
- Nationwide Children's Hospital, The Ohio State University, Columbus, OH, USA
| | - Cheryl Shoubridge
- Department of Paediatrics, School of Peadiatrics and Reproductive Health, University of Adelaide, Adelaide, SA, Australia.,Robinson Research Institute, Faculty of Health Sciences, University of Adelaide, Adelaide, SA, Australia
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Kato M. Genotype-phenotype correlation in neuronal migration disorders and cortical dysplasias. Front Neurosci 2015; 9:181. [PMID: 26052266 PMCID: PMC4439546 DOI: 10.3389/fnins.2015.00181] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 05/06/2015] [Indexed: 11/29/2022] Open
Abstract
Neuronal migration disorders are human (or animal) diseases that result from a disruption in the normal movement of neurons from their original birth site to their final destination during early development. As a consequence, the neurons remain somewhere along their migratory route, their location depending on the pathological mechanism and its severity. The neurons form characteristic abnormalities, which are morphologically classified into several types, such as lissencephaly, heterotopia, and cobblestone dysplasia. Polymicrogyria is classified as a group of malformations that appear secondary to post-migration development; however, recent findings of the underlying molecular mechanisms reveal overlapping processes in the neuronal migration and post-migration development stages. Mutations of many genes are involved in neuronal migration disorders, such as LIS1 and DCX in classical lissencephaly spectrum, TUBA1A in microlissencephaly with agenesis of the corpus callosum, and RELN and VLDLR in lissencephaly with cerebellar hypoplasia. ARX is of particular interest from basic and clinical perspectives because it is critically involved in tangential migration of GABAergic interneurons in the forebrain and its mutations cause a variety of phenotypes ranging from hydranencephaly or lissencephaly to early-onset epileptic encephalopathies, including Ohtahara syndrome and infantile spasms or intellectual disability with no brain malformations. The recent advances in gene and genome analysis technologies will enable the genetic basis of neuronal migration disorders to be unraveled, which, in turn, will facilitate genotype-phenotype correlations to be determined.
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Affiliation(s)
- Mitsuhiro Kato
- Department of Pediatrics, Yamagata University Faculty of Medicine Yamagata, Japan
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Shen E, Shulha H, Weng Z, Akbarian S. Regulation of histone H3K4 methylation in brain development and disease. Philos Trans R Soc Lond B Biol Sci 2015; 369:rstb.2013.0514. [PMID: 25135975 DOI: 10.1098/rstb.2013.0514] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The growing list of mutations implicated in monogenic disorders of the developing brain includes at least seven genes (ARX, CUL4B, KDM5A, KDM5C, KMT2A, KMT2C, KMT2D) with loss-of-function mutations affecting proper regulation of histone H3 lysine 4 methylation, a chromatin mark which on a genome-wide scale is broadly associated with active gene expression, with its mono-, di- and trimethylated forms differentially enriched at promoter and enhancer and other regulatory sequences. In addition to these rare genetic syndromes, dysregulated H3K4 methylation could also play a role in the pathophysiology of some cases diagnosed with autism or schizophrenia, two conditions which on a genome-wide scale are associated with H3K4 methylation changes at hundreds of loci in a subject-specific manner. Importantly, the reported alterations for some of the diseased brain specimens included a widespread broadening of H3K4 methylation profiles at gene promoters, a process that could be regulated by the UpSET(KMT2E/MLL5)-histone deacetylase complex. Furthermore, preclinical studies identified maternal immune activation, parental care and monoaminergic drugs as environmental determinants for brain-specific H3K4 methylation. These novel insights into the epigenetic risk architectures of neurodevelopmental disease will be highly relevant for efforts aimed at improved prevention and treatment of autism and psychosis spectrum disorders.
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Affiliation(s)
- Erica Shen
- Department of Psychiatry, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Hennady Shulha
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA 01604, USA
| | - Zhiping Weng
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA 01604, USA
| | - Schahram Akbarian
- Department of Psychiatry, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
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Hunter JM, Kiefer J, Balak CD, Jooma S, Ahearn ME, Hall JG, Baumbach-Reardon L. Review of X-linked syndromes with arthrogryposis or early contractures-aid to diagnosis and pathway identification. Am J Med Genet A 2015; 167A:931-73. [DOI: 10.1002/ajmg.a.36934] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 12/05/2014] [Indexed: 02/03/2023]
Affiliation(s)
- Jesse M. Hunter
- Integrated Functional Cancer Genomics; Translational Genomics Research Institute; Phoenix Arizona
| | - Jeff Kiefer
- Knowledge Mining; Translational Genomics Research Institute; Phoenix Arizona
| | - Christopher D. Balak
- Integrated Functional Cancer Genomics; Translational Genomics Research Institute; Phoenix Arizona
| | - Sonya Jooma
- Integrated Functional Cancer Genomics; Translational Genomics Research Institute; Phoenix Arizona
| | - Mary Ellen Ahearn
- Integrated Functional Cancer Genomics; Translational Genomics Research Institute; Phoenix Arizona
| | - Judith G. Hall
- Departments of Medical Genetics and Pediatrics; University of British Columbia and BC Children's Hospital Vancouver; British Columbia Canada
| | - Lisa Baumbach-Reardon
- Integrated Functional Cancer Genomics; Translational Genomics Research Institute; Phoenix Arizona
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Marques I, Sá MJ, Soares G, Mota MDC, Pinheiro C, Aguiar L, Amado M, Soares C, Calado A, Dias P, Sousa AB, Fortuna AM, Santos R, Howell KB, Ryan MM, Leventer RJ, Sachdev R, Catford R, Friend K, Mattiske TR, Shoubridge C, Jorge P. Unraveling the pathogenesis of ARX polyalanine tract variants using a clinical and molecular interfacing approach. Mol Genet Genomic Med 2015; 3:203-14. [PMID: 26029707 PMCID: PMC4444162 DOI: 10.1002/mgg3.133] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Revised: 01/13/2015] [Accepted: 01/15/2015] [Indexed: 12/22/2022] Open
Abstract
The Aristaless-related homeobox (ARX) gene is implicated in intellectual disability with the most frequent pathogenic mutations leading to expansions of the first two polyalanine tracts. Here, we describe analysis of the ARX gene outlining the approaches in the Australian and Portuguese setting, using an integrated clinical and molecular strategy. We report variants in the ARX gene detected in 19 patients belonging to 17 families. Seven pathogenic variants, being expansion mutations in both polyalanine tract 1 and tract 2, were identifyed, including a novel mutation in polyalanine tract 1 that expands the first tract to 20 alanines. This precise number of alanines is sufficient to cause pathogenicity when expanded in polyalanine tract 2. Five cases presented a probably non-pathogenic variant, including the novel HGVS: c.441_455del, classified as unlikely disease causing, consistent with reports that suggest that in frame deletions in polyalanine stretches of ARX rarely cause intellectual disability. In addition, we identified five cases with a variant of unclear pathogenic significance. Owing to the inconsistent ARX variants description, publications were reviewed and ARX variant classifications were standardized and detailed unambiguously according to recommendations of the Human Genome Variation Society. In the absence of a pathognomonic clinical feature, we propose that molecular analysis of the ARX gene should be included in routine diagnostic practice in individuals with either nonsyndromic or syndromic intellectual disability. A definitive diagnosis of ARX-related disorders is crucial for an adequate clinical follow-up and accurate genetic counseling of at-risk family members.
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Affiliation(s)
- Isabel Marques
- Unidade de Genética Molecular, Centro de Genética Médica Doutor Jacinto Magalhães, Centro Hospitalar do Porto, EPE Porto, Portugal ; Unit for Multidisciplinary Research in Biomedicine, UMIB, ICBAS-UP Porto, Portugal
| | - Maria João Sá
- Unidade de Genética Médica, Centro de Genética Médica Doutor Jacinto Magalhães, Centro Hospitalar do Porto, EPE Porto, Portugal ; Unit for Multidisciplinary Research in Biomedicine, UMIB, ICBAS-UP Porto, Portugal
| | - Gabriela Soares
- Unidade de Genética Médica, Centro de Genética Médica Doutor Jacinto Magalhães, Centro Hospitalar do Porto, EPE Porto, Portugal
| | - Maria do Céu Mota
- Department of Pediatrics, Centro Hospitalar do Porto, EPE Porto, Portugal
| | - Carla Pinheiro
- Department of Pediatrics, Hospital Santa Maria Maior, EPE Barcelos, Portugal
| | - Lisa Aguiar
- Department of Pediatrics, Hospital Distrital de Santarém, EPE Santarém, Portugal
| | - Marta Amado
- Department of Pediatrics, Unidade Hospitalar de Portimão, Centro Hospitalar do Algarve Portimão, Portugal
| | - Christina Soares
- Department of Pediatrics, Unidade Hospitalar de Portimão, Centro Hospitalar do Algarve Portimão, Portugal
| | - Angelina Calado
- Department of Pediatrics, Unidade Hospitalar de Portimão, Centro Hospitalar do Algarve Portimão, Portugal
| | - Patrícia Dias
- Department of Genetics, Hospital de Santa Maria Lisboa, Portugal
| | - Ana Berta Sousa
- Department of Genetics, Hospital de Santa Maria Lisboa, Portugal
| | - Ana Maria Fortuna
- Unidade de Genética Médica, Centro de Genética Médica Doutor Jacinto Magalhães, Centro Hospitalar do Porto, EPE Porto, Portugal ; Unit for Multidisciplinary Research in Biomedicine, UMIB, ICBAS-UP Porto, Portugal
| | - Rosário Santos
- Unidade de Genética Molecular, Centro de Genética Médica Doutor Jacinto Magalhães, Centro Hospitalar do Porto, EPE Porto, Portugal ; Unit for Multidisciplinary Research in Biomedicine, UMIB, ICBAS-UP Porto, Portugal
| | - Katherine B Howell
- Department of Neurology, Royal Children's Hospital Melbourne, Victoria, Australia ; Murdoch Childrens Research Institute Melbourne, Victoria, Australia, 3052 ; University of Melbourne Department of Paediatrics Melbourne, Victoria, Australia, 3052
| | - Monique M Ryan
- Department of Neurology, Royal Children's Hospital Melbourne, Victoria, Australia ; Murdoch Childrens Research Institute Melbourne, Victoria, Australia, 3052 ; University of Melbourne Department of Paediatrics Melbourne, Victoria, Australia, 3052
| | - Richard J Leventer
- Department of Neurology, Royal Children's Hospital Melbourne, Victoria, Australia ; Murdoch Childrens Research Institute Melbourne, Victoria, Australia, 3052 ; University of Melbourne Department of Paediatrics Melbourne, Victoria, Australia, 3052
| | - Rani Sachdev
- Department of Medical Genetics, Sydney Children's Hospital High St., Randwick, New South Wales, 2031, Australia
| | - Rachael Catford
- SA Pathology at the Women's and Children's Hospital North Adelaide, South Australia, Australia
| | - Kathryn Friend
- SA Pathology at the Women's and Children's Hospital North Adelaide, South Australia, Australia
| | - Tessa R Mattiske
- Department of Paediatrics, University of Adelaide Adelaide, South Australia, 5006, Australia ; Robinson Research Institute, University of Adelaide Adelaide, South Australia, 5006, Australia
| | - Cheryl Shoubridge
- Department of Paediatrics, University of Adelaide Adelaide, South Australia, 5006, Australia ; Robinson Research Institute, University of Adelaide Adelaide, South Australia, 5006, Australia
| | - Paula Jorge
- Unidade de Genética Molecular, Centro de Genética Médica Doutor Jacinto Magalhães, Centro Hospitalar do Porto, EPE Porto, Portugal ; Unit for Multidisciplinary Research in Biomedicine, UMIB, ICBAS-UP Porto, Portugal
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Abstract
OBJECTIVES Severe congenital diarrhea occurs in approximately half of patients with Aristaless-Related Homeobox (ARX) null mutations. The cause of this diarrhea is unknown. In a mouse model of intestinal Arx deficiency, the prevalence of a subset of enteroendocrine cells is altered, leading to diarrhea. Because polyalanine expansions within the ARX protein are the most common mutations found in ARX-related disorders, we sought to characterize the enteroendocrine population in human tissue of an ARX mutation and in a mouse model of the corresponding polyalanine expansion (Arx). METHODS Immunohistochemistry and quantitative real-time polymerase chain reaction were the primary modalities used to characterize the enteroendocrine populations. Daily weights were determined for the growth curves, and Oil-Red-O staining on stool and tissue identified neutral fats. RESULTS An expansion of 7 alanines in the first polyalanine tract of both human ARX and mouse Arx altered enteroendocrine differentiation. In human tissue, cholecystokinin, glucagon-like peptide 1, and somatostatin populations were reduced, whereas the chromogranin A population was unchanged. In the mouse model, cholecystokinin and glucagon-like peptide 1 populations were also lost, although the somatostatin-expressing population was increased. The ARX protein was present in human tissue, whereas the Arx protein was degraded in the mouse intestine. CONCLUSIONS ARX/Arx is required for the specification of a subset of enteroendocrine cells in both humans and mice. Owing to protein degradation, the Arx mouse recapitulates findings of the intestinal Arx null model, but is not able to further the study of the differential effects of the ARX protein on its transcriptional targets in the intestine.
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Olivetti PR, Maheshwari A, Noebels JL. Neonatal estradiol stimulation prevents epilepsy in Arx model of X-linked infantile spasms syndrome. Sci Transl Med 2014; 6:220ra12. [PMID: 24452264 DOI: 10.1126/scitranslmed.3007231] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Infantile spasms are a catastrophic form of pediatric epilepsy with inadequate treatment. In patients, mutation of ARX, a transcription factor selectively expressed in neuronal precursors and adult inhibitory interneurons, impairs cell migration and causes a major inherited subtype of the disease X-linked infantile spasms syndrome. Using an animal model, the Arx((GCG)10+7) mouse, we determined that brief estradiol (E2) administration during early postnatal development prevented spasms in infancy and seizures in adult mutants. E2 was ineffective when delivered after puberty or 30 days after birth. Early E2 treatment altered mRNA levels of three downstream targets of Arx (Shox2, Ebf3, and Lgi1) and restored depleted interneuron populations without increasing GABAergic synaptic density. Postnatal E2 treatment may induce lasting transcriptional changes that lead to enduring disease modification and could potentially serve as a therapy for inherited interneuronopathies.
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Affiliation(s)
- Pedro R Olivetti
- Blue Bird Circle Developmental Neurogenetics Laboratory, Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA
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Functionally significant, rare transcription factor variants in tetralogy of Fallot. PLoS One 2014; 9:e95453. [PMID: 25093829 PMCID: PMC4122343 DOI: 10.1371/journal.pone.0095453] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 03/27/2014] [Indexed: 01/06/2023] Open
Abstract
Objective Rare variants in certain transcription factors involved in cardiac development cause Mendelian forms of congenital heart disease. The purpose of this study was to systematically assess the frequency of rare transcription factor variants in sporadic patients with the cardiac outflow tract malformation tetralogy of Fallot (TOF). Methods and Results We sequenced the coding, 5′UTR, and 3′UTR regions of twelve transcription factor genes implicated in cardiac outflow tract development (NKX2.5, GATA4, ISL1, TBX20, MEF2C, BOP/SMYD1, HAND2, FOXC1, FOXC2, FOXH, FOXA2 and TBX1) in 93 non-syndromic, non-Mendelian TOF cases. We also analysed Illumina Human 660W-Quad SNP Array data for copy number variants in these genes; none were detected. Four of the rare variants detected have previously been shown to affect transactivation in in vitro reporter assays: FOXC1 p.P297S, FOXC2 p.Q444R, FOXH1 p.S113T and TBX1 p.P43_G61del PPPPRYDPCAAAAPGAPGP. Two further rare variants, HAND2 p.A25_A26insAA and FOXC1 p.G378_G380delGGG, A488_491delAAAA, affected transactivation in in vitro reporter assays. Each of these six functionally significant variants was present in a single patient in the heterozygous state; each of the four for which parental samples were available were maternally inherited. Thus in the 93 TOF cases we identified six functionally significant mutations in the secondary heart field transcriptional network. Significance This study indicates that rare genetic variants in the secondary heart field transcriptional network with functional effects on protein function occur in 3–13% of patients with TOF. This is the first report of a functionally significant HAND2 mutation in a patient with congenital heart disease.
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Fry AE, Cushion TD, Pilz DT. The genetics of lissencephaly. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2014; 166C:198-210. [DOI: 10.1002/ajmg.c.31402] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Michaud JL, Lachance M, Hamdan FF, Carmant L, Lortie A, Diadori P, Major P, Meijer IA, Lemyre E, Cossette P, Mefford HC, Rouleau GA, Rossignol E. The genetic landscape of infantile spasms. Hum Mol Genet 2014; 23:4846-58. [PMID: 24781210 DOI: 10.1093/hmg/ddu199] [Citation(s) in RCA: 136] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Infantile spasms (IS) is an early-onset epileptic encephalopathy of unknown etiology in ∼40% of patients. We hypothesized that unexplained IS cases represent a large collection of rare single-gene disorders. We investigated 44 children with unexplained IS using comparative genomic hybridisation arrays (aCGH) (n = 44) followed by targeted sequencing of 35 known epilepsy genes (n = 8) or whole-exome sequencing (WES) of familial trios (n = 18) to search for rare inherited or de novo mutations. aCGH analysis revealed de novo variants in 7% of patients (n = 3/44), including a distal 16p11.2 duplication, a 15q11.1q13.1 tetrasomy and a 2q21.3-q22.2 deletion. Furthermore, it identified a pathogenic maternally inherited Xp11.2 duplication. Targeted sequencing was informative for ARX (n = 1/14) and STXBP1 (n = 1/8). In contrast, sequencing of a panel of 35 known epileptic encephalopathy genes (n = 8) did not identify further mutations. Finally, WES (n = 18) was very informative, with an excess of de novo mutations identified in genes predicted to be involved in neurodevelopmental processes and/or known to be intolerant to functional variations. Several pathogenic mutations were identified, including de novo mutations in STXBP1, CASK and ALG13, as well as recessive mutations in PNPO and ADSL, together explaining 28% of cases (5/18). In addition, WES identified 1-3 de novo variants in 64% of remaining probands, pointing to several interesting candidate genes. Our results indicate that IS are genetically heterogeneous with a major contribution of de novo mutations and that WES is significantly superior to targeted re-sequencing in identifying detrimental genetic variants involved in IS.
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Affiliation(s)
- Jacques L Michaud
- Department of Pediatrics and Department of Neurosciences, Université de Montréal, Montréal, QC, Canada, CHU Ste-Justine Research Center, Montréal, QC, Canada
| | | | - Fadi F Hamdan
- CHU Ste-Justine Research Center, Montréal, QC, Canada
| | - Lionel Carmant
- Department of Pediatrics and Department of Neurosciences, Université de Montréal, Montréal, QC, Canada, CHU Ste-Justine Research Center, Montréal, QC, Canada
| | - Anne Lortie
- Department of Pediatrics and Department of Neurosciences, Université de Montréal, Montréal, QC, Canada, CHU Ste-Justine Research Center, Montréal, QC, Canada
| | - Paola Diadori
- Department of Pediatrics and Department of Neurosciences, Université de Montréal, Montréal, QC, Canada, CHU Ste-Justine Research Center, Montréal, QC, Canada
| | - Philippe Major
- Department of Pediatrics and Department of Neurosciences, Université de Montréal, Montréal, QC, Canada, CHU Ste-Justine Research Center, Montréal, QC, Canada
| | - Inge A Meijer
- CHU Ste-Justine Research Center, Montréal, QC, Canada
| | - Emmanuelle Lemyre
- Department of Pediatrics and CHU Ste-Justine Research Center, Montréal, QC, Canada
| | - Patrick Cossette
- Department of Neurosciences, Université de Montréal, Montréal, QC, Canada, CHUM, Montréal, QC, Canada
| | - Heather C Mefford
- Department of Pediatrics, University of Washington, Seattle, WA, USA and
| | - Guy A Rouleau
- Department of Neurosciences, Montreal Neurological Institute, McGill University, Montréal, QC, Canada
| | - Elsa Rossignol
- Department of Pediatrics and Department of Neurosciences, Université de Montréal, Montréal, QC, Canada, CHU Ste-Justine Research Center, Montréal, QC, Canada,
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Curie A, Nazir T, Brun A, Paulignan Y, Reboul A, Delange K, Cheylus A, Bertrand S, Rochefort F, Bussy G, Marignier S, Lacombe D, Chiron C, Cossée M, Leheup B, Philippe C, Laugel V, De Saint Martin A, Sacco S, Poirier K, Bienvenu T, Souville I, Gilbert-Dussardier B, Bieth E, Kauffmann D, Briot P, de Fréminville B, Prieur F, Till M, Rooryck-Thambo C, Mortemousque I, Bobillier-Chaumont I, Toutain A, Touraine R, Sanlaville D, Chelly J, Freeman S, Kong J, Hadjikhani N, Gollub RL, Roy A, des Portes V. The c.429_452 duplication of the ARX gene: a unique developmental-model of limb kinetic apraxia. Orphanet J Rare Dis 2014; 9:25. [PMID: 24528893 PMCID: PMC4016261 DOI: 10.1186/1750-1172-9-25] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Accepted: 01/22/2014] [Indexed: 12/16/2022] Open
Abstract
Background The c.429_452dup24 of the ARX gene is a rare genetic anomaly, leading to X-Linked Intellectual Disability without brain malformation. While in certain cases c.429_452dup24 has been associated with specific clinical patterns such as Partington syndrome, the consequence of this mutation has been also often classified as “non-specific Intellectual Disability”. The present work aims at a more precise description of the clinical features linked to the c.429_452dup24 mutation. Methods We clinically reviewed all affected patients identified in France over a five-year period, i.e. 27 patients from 12 different families. Detailed cognitive, behavioural, and motor evaluation, as well as standardized videotaped assessments of oro-lingual and gestural praxis, were performed. In a sub-group of 13 ARX patients, kinematic and MRI studies were further accomplished to better characterize the motor impairment prevalent in the ARX patients group. To ensure that data were specific to the ARX gene mutation and did not result from low-cognitive functioning per se, a group of 27 age- and IQ-matched Down syndrome patients served as control. Results Neuropsychological and motor assessment indicated that the c.429_452dup24 mutation constitutes a recognizable clinical syndrome: ARX patients exhibiting Intellectual Disability, without primary motor impairment, but with a very specific upper limb distal motor apraxia associated with a pathognomonic hand-grip. Patients affected with the so-called Partington syndrome, which involves major hand dystonia and orolingual apraxia, exhibit the most severe symptoms of the disorder. The particular “reach and grip” impairment which was observed in all ARX patients, but not in Down syndrome patients, was further characterized by the kinematic data: (i) loss of preference for the index finger when gripping an object, (ii) major impairment of fourth finger deftness, and (iii) a lack of pronation movements. This lack of distal movement coordination exhibited by ARX patients is associated with the loss of independent digital dexterity and is similar to the distortion of individual finger movements and posture observed in Limb Kinetic Apraxia. Conclusion These findings suggest that the ARX c.429_452dup24 mutation may be a developmental model for Limb Kinetic Apraxia.
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Affiliation(s)
- Aurore Curie
- Centre de Référence « Déficiences Intellectuelles de Causes Rares », Hôpital Femme Mère Enfant, Hospices Civils de Lyon, F-69677 Bron, France.
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Abstract
In humans, genomic DNA is organized in 23 chromosome pairs coding for roughly 25,000 genes. Not all of them are active at all times. During development, a broad range of different cell types needs to be generated in a highly ordered and reproducible manner, requiring selective gene expression programs. Epigenetics can be regarded as the information management system that is able to index or bookmark distinct regions in our genome to regulate the readout of DNA. It further comprises the molecular memory of any given cell, allowing it to store information of previously experienced external (e.g., environmental) or internal (e.g., developmental) stimuli, to learn from this experience and to respond. The underlying epigenetic mechanisms can be synergistic, antagonistic, or mutually exclusive and their large variety combined with the variability and interdependence is thought to provide the molecular basis for any phenotypic variation in physiological and pathological conditions. Thus, widespread reconfiguration of the epigenome is not only a key feature of neurodevelopment, brain maturation, and adult brain function but also disease.
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Affiliation(s)
- Katja Kobow
- Department of Neuropathology, University Hospital Erlangen, Schwabachanlage, Erlangen, Germany
| | - Ingmar Blümcke
- Department of Neuropathology, University Hospital Erlangen, Schwabachanlage, Erlangen, Germany.
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49
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Abstract
Advances in genetic tools and sequencing technology in the past few years have vastly expanded our understanding of the genetics of neurodevelopmental disorders. Recent high-throughput sequencing analyses of structural brain malformations, cognitive and neuropsychiatric disorders, and localized cortical dysplasias have uncovered a diverse genetic landscape beyond classic Mendelian patterns of inheritance. The underlying genetic causes of neurodevelopmental disorders implicate numerous cell biological pathways critical for normal brain development.
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Affiliation(s)
- Wen F Hu
- Division of Genetics and Genomics, Department of Medicine; Manton Center for Orphan Disease Research; and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, Massachusetts 02115; , ,
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50
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Deng H, Zheng W, Song Z. Genetics, Molecular Biology, and Phenotypes of X-Linked Epilepsy. Mol Neurobiol 2013; 49:1166-80. [DOI: 10.1007/s12035-013-8589-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2013] [Accepted: 11/05/2013] [Indexed: 11/25/2022]
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