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Akula SK, Quiroz V, D'Gama AM, Chiu MY, Koh HY, Saffari A, Zaman Z, Tam A, Srouji R, Valentine R, Wiltrout K, Pinto A, Harini C, Pearl PL, Poduri A, Ebrahimi‐Fakhari D. The spectrum of movement disorders in young children with ARX-related epilepsy-dyskinesia syndrome. Ann Clin Transl Neurol 2024; 11:1643-1647. [PMID: 38711225 PMCID: PMC11187834 DOI: 10.1002/acn3.52055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 03/06/2024] [Accepted: 03/18/2024] [Indexed: 05/08/2024] Open
Abstract
Children with developmental and epileptic encephalopathies often present with co-occurring dyskinesias. Pathogenic variants in ARX cause a pleomorphic syndrome that includes infantile epilepsy with a variety of movement disorders ranging from focal hand dystonia to generalized dystonia with frequent status dystonicus. In this report, we present three patients with severe movement disorders as part of ARX-associated epilepsy-dyskinesia syndrome, including a patient with a novel pathogenic missense variant (p.R371G). These cases illustrate diagnostic and management challenges of ARX-related disorder and shed light on broader challenges concerning epilepsy-dyskinesia syndromes.
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Affiliation(s)
- Shyam K. Akula
- Movement Disorders Program, Department of Neurology, Boston Children's HospitalHarvard Medical SchoolBostonMassachusettsUSA
- Division of Genetics and Genomics, Boston Children's HospitalHarvard Medical SchoolBostonMassachusetts02115USA
| | - Vicente Quiroz
- Movement Disorders Program, Department of Neurology, Boston Children's HospitalHarvard Medical SchoolBostonMassachusettsUSA
| | - Alissa M. D'Gama
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's HospitalHarvard Medical SchoolBostonMassachusettsUSA
| | - Michelle Y. Chiu
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's HospitalHarvard Medical SchoolBostonMassachusettsUSA
| | - Hyun Yong Koh
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's HospitalHarvard Medical SchoolBostonMassachusettsUSA
| | - Afshin Saffari
- Movement Disorders Program, Department of Neurology, Boston Children's HospitalHarvard Medical SchoolBostonMassachusettsUSA
- Division of Child Neurology and Inherited Metabolic DiseasesHeidelberg University HospitalHeidelbergGermany
| | - Zainab Zaman
- Movement Disorders Program, Department of Neurology, Boston Children's HospitalHarvard Medical SchoolBostonMassachusettsUSA
| | - Amy Tam
- Movement Disorders Program, Department of Neurology, Boston Children's HospitalHarvard Medical SchoolBostonMassachusettsUSA
| | - Rasha Srouji
- Movement Disorders Program, Department of Neurology, Boston Children's HospitalHarvard Medical SchoolBostonMassachusettsUSA
| | - Rozalia Valentine
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's HospitalHarvard Medical SchoolBostonMassachusettsUSA
| | - Kimberly Wiltrout
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's HospitalHarvard Medical SchoolBostonMassachusettsUSA
| | - Anna Pinto
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's HospitalHarvard Medical SchoolBostonMassachusettsUSA
| | - Chellamani Harini
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's HospitalHarvard Medical SchoolBostonMassachusettsUSA
| | - Phillip L. Pearl
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's HospitalHarvard Medical SchoolBostonMassachusettsUSA
| | - Annapurna Poduri
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's HospitalHarvard Medical SchoolBostonMassachusettsUSA
| | - Darius Ebrahimi‐Fakhari
- Movement Disorders Program, Department of Neurology, Boston Children's HospitalHarvard Medical SchoolBostonMassachusettsUSA
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Snyder HE, Jain P, RamachandranNair R, Jones KC, Whitney R. Genetic Advancements in Infantile Epileptic Spasms Syndrome and Opportunities for Precision Medicine. Genes (Basel) 2024; 15:266. [PMID: 38540325 PMCID: PMC10970414 DOI: 10.3390/genes15030266] [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: 01/19/2024] [Revised: 02/13/2024] [Accepted: 02/20/2024] [Indexed: 06/15/2024] Open
Abstract
Infantile epileptic spasms syndrome (IESS) is a devastating developmental epileptic encephalopathy (DEE) consisting of epileptic spasms, as well as one or both of developmental regression or stagnation and hypsarrhythmia on EEG. A myriad of aetiologies are associated with the development of IESS; broadly, 60% of cases are thought to be structural, metabolic or infectious in nature, with the remainder genetic or of unknown cause. Epilepsy genetics is a growing field, and over 28 copy number variants and 70 single gene pathogenic variants related to IESS have been discovered to date. While not exhaustive, some of the most commonly reported genetic aetiologies include trisomy 21 and pathogenic variants in genes such as TSC1, TSC2, CDKL5, ARX, KCNQ2, STXBP1 and SCN2A. Understanding the genetic mechanisms of IESS may provide the opportunity to better discern IESS pathophysiology and improve treatments for this condition. This narrative review presents an overview of our current understanding of IESS genetics, with an emphasis on animal models of IESS pathogenesis, the spectrum of genetic aetiologies of IESS (i.e., chromosomal disorders, single-gene disorders, trinucleotide repeat disorders and mitochondrial disorders), as well as available genetic testing methods and their respective diagnostic yields. Future opportunities as they relate to precision medicine and epilepsy genetics in the treatment of IESS are also explored.
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Affiliation(s)
- Hannah E. Snyder
- Division of Neurology, Department of Paediatrics, McMaster University, Hamilton, ON L8N 3Z5, Canada (R.R.)
| | - Puneet Jain
- Division of Neurology, Department of Paediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON M5G 1E8, Canada
| | - Rajesh RamachandranNair
- Division of Neurology, Department of Paediatrics, McMaster University, Hamilton, ON L8N 3Z5, Canada (R.R.)
| | - Kevin C. Jones
- Division of Neurology, Department of Paediatrics, McMaster University, Hamilton, ON L8N 3Z5, Canada (R.R.)
| | - Robyn Whitney
- Division of Neurology, Department of Paediatrics, McMaster University, Hamilton, ON L8N 3Z5, Canada (R.R.)
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Nieto-Estevez V, Varma P, Mirsadeghi S, Caballero J, Gamero-Alameda S, Hosseini A, Goswami S, Silvosa MJ, Thodeson DM, Lybrand ZR, Giugliano M, Navara C, Hsieh J. Dual effects of ARX poly-alanine mutations in human cortical and interneuron development. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.25.577271. [PMID: 38328230 PMCID: PMC10849640 DOI: 10.1101/2024.01.25.577271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Mutations in ARX , an X-linked gene, are implicated in a wide spectrum of neurological disorders including patients who have intellectual disability and epilepsy. Mouse models have shown that Arx is critical for cortical development and interneuron migration, however they do not recapitulate the full phenotype observed in patients. Moreover, the epilepsy in many patients with poly-alanine tract expansion (PAE) mutations in ARX show pharmacoresistance, emphasizing the need to develop new treatments. Here, we used human neural organoid models to study the consequences of PAE mutations, one of the most prevalent mutations in ARX . We found that PAE mutations result in an early increase in radial glia cells and intermediate progenitor cells, and premature differentiation leading to a loss of cortical neurons at later timepoints. Moreover, ARX expression is upregulated in CO derived from patient at 30 DIV which alters the expression of CDKN1C , SFRP1 , DLK1 and FABP7 , among others. We also found a cell autonomously enhanced interneuron migration, which can be rescued by CXCR4 inhibition. Furthermore, ARX PAE assembloids had hyper-activity and synchrony evident from the early stages. These data provide novel insights to the pathogenesis of these and likely related human neurological disorders and identifies a critical window for therapeutic interventions.
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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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Phenotypes of a female patient with novel de novo frameshift ARX variant identified by whole-exome sequencing: a case report. Ann Med Surg (Lond) 2023; 85:236-241. [PMID: 36845779 PMCID: PMC9949785 DOI: 10.1097/ms9.0000000000000197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 12/24/2022] [Indexed: 02/28/2023] Open
Abstract
Variants in the aristaless-related homeobox (ARX) gene cause a diverse spectrum of phenotypes of neurodevelopmental disorders (NDD) in male patients. This article describes the role of genetic testing using whole-exome sequencing (WES) in detecting a novel de novo frameshift variant in the ARX gene in a female patient with autism, seizure, and global developmental delay. Case presentation A 2-year-old girl with frequent seizures, global developmental delay, and autistic features was referred to our hospital. She was the second child of consanguineous non-affected parents. She had a high forehead, mildly prominent ears, and prominent nasal root. A generalized epileptiform discharge was noted in her electroencephalography. Brain MRI revealed corpus callosum agenesis, cerebral atrophy, and a left parafalcine cyst. The WES result showed a likely pathogenic variant identified as a novel de novo deletion in exon 4 of the ARX gene, which creates a frameshift variant. The patient is on dual therapy of antiepilepsy drugs, physiotherapy, speech therapy, occupational therapy, and oral motor exercises. Clinical discussion Variants in the ARX gene can result in various phenotypes in males transmitted from asymptomatic carrier females. However, several reports showed that the ARX variants might cause phenotypes in females with milder symptoms than affected males. Conclusion We report a novel de novo ARX variant in an affected female with a NDD. Our study confirms that the ARX variant might cause remarkable pleiotropy phenotypes in females. Moreover, WES could help to identify the pathogenic variant in NDD patients with diverse phenotypes.
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6
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Veltra D, Tilemis FN, Marinakis NM, Svingou M, Mitrakos A, Kosma K, Tsoutsou I, Makrythanasis P, Theodorou V, Katsalouli M, Vorgia P, Niotakis G, Vartzelis G, Dinopoulos A, Evangeliou A, Mouskou S, Korona A, Mastroyianni S, Papavasiliou A, Tzetis M, Pons R, Traeger-Synodinos J, Sofocleous C. Combined exome analysis and exome depth assessment achieve a high diagnostic yield in an epilepsy case series, revealing significant genomic heterogeneity and novel mechanisms. Expert Rev Mol Diagn 2023; 23:85-103. [PMID: 36714946 DOI: 10.1080/14737159.2023.2173578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
OBJECTIVES Genetics of epilepsy are highly heterogeneous and complex. Lesions detected involve genes encoding various types of channels, transcription factors, and other proteins implicated in numerous cellular processes, such as synaptogenesis. Consequently, a wide spectrum of clinical presentations and overlapping phenotypes hinders differential diagnosis and highlights the need for molecular investigations toward delineation of underlying mechanisms and final diagnosis. Characterization of defects may also contribute valuable data on genetic landscapes and networks implicated in epileptogenesis. METHODS This study reports on genetic findings from exome sequencing (ES) data of 107 patients with variable types of seizures, with or without additional symptoms, in the context of neurodevelopmental disorders. RESULTS Multidisciplinary evaluation of ES, including ancillary detection of copy number variants (CNVs) with the ExomeDepth tool, supported a definite diagnosis in 59.8% of the patients, reflecting one of the highest diagnostic yields in epilepsy. CONCLUSION Emerging advances of next-generation technologies and 'in silico' analysis tools offer the possibility to simultaneously detect several types of variations. Wide assessment of variable findings, specifically those found to be novel and least expected, reflects the ever-evolving genetic landscape of seizure development, potentially beneficial for increased opportunities for trial recruitment and enrollment, and optimized, even personalized, medical management.
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Affiliation(s)
- Danai Veltra
- Laboratory of Medical Genetics, Medical School, National and Kapodistrian University of Athens, St. Sophia's Children's Hospital, Athens, Greece
| | - Faidon-Nikolaos Tilemis
- Laboratory of Medical Genetics, Medical School, National and Kapodistrian University of Athens, St. Sophia's Children's Hospital, Athens, Greece.,Research University Institute for the Study and Prevention of Genetic and Malignant Disease of Childhood, National and Kapodistrian University of Athens, St. Sophia's Children's Hospital, Athens, Greece
| | - Nikolaos M Marinakis
- Laboratory of Medical Genetics, Medical School, National and Kapodistrian University of Athens, St. Sophia's Children's Hospital, Athens, Greece.,Research University Institute for the Study and Prevention of Genetic and Malignant Disease of Childhood, National and Kapodistrian University of Athens, St. Sophia's Children's Hospital, Athens, Greece
| | - Maria Svingou
- Laboratory of Medical Genetics, Medical School, National and Kapodistrian University of Athens, St. Sophia's Children's Hospital, Athens, Greece
| | - Anastasios Mitrakos
- Laboratory of Medical Genetics, Medical School, National and Kapodistrian University of Athens, St. Sophia's Children's Hospital, Athens, Greece
| | - Konstantina Kosma
- Laboratory of Medical Genetics, Medical School, National and Kapodistrian University of Athens, St. Sophia's Children's Hospital, Athens, Greece
| | - Irene Tsoutsou
- Laboratory of Medical Genetics, Medical School, National and Kapodistrian University of Athens, St. Sophia's Children's Hospital, Athens, Greece
| | - Periklis Makrythanasis
- Laboratory of Medical Genetics, Medical School, National and Kapodistrian University of Athens, St. Sophia's Children's Hospital, Athens, Greece.,Department of Genetic Medicine and Development, Medical School, University of Geneva, Geneva, Switzerland.,Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Virginia Theodorou
- Pediatric Neurology Department, St. Sophia's Children's Hospital, Athens, Greece
| | - Marina Katsalouli
- Pediatric Neurology Department, St. Sophia's Children's Hospital, Athens, Greece
| | - Pelagia Vorgia
- Agrifood and Life Sciences Institute, Hellenic Mediterranean University, Heraklion, Crete, Greece
| | - Georgios Niotakis
- Pediatric Neurology Department, Venizelion Hospital, Heraklion, Greece
| | - Georgios Vartzelis
- Second Department of Pediatrics, Medical School, National and Kapodistrian University of Athens, P. & A. Kyriakou Children's Hospital, Athens, Greece
| | - Argirios Dinopoulos
- Forth Department of Pediatrics, Medical School, National and Kapodistrian University of Athens, General Hospital of Athens Attikon, Athens, Greece
| | - Athanasios Evangeliou
- Aristotle University of Thessaloniki, Papageorgiou General Hospital, Thessaloniki, Greece
| | - Stella Mouskou
- Pediatric Neurology Department, P. & A. Kyriakou Children's Hospital, Athens, Greece
| | - Anastasia Korona
- Pediatric Neurology Department, P. & A. Kyriakou Children's Hospital, Athens, Greece
| | - Sotiria Mastroyianni
- Pediatric Neurology Department, P. & A. Kyriakou Children's Hospital, Athens, Greece
| | | | - Maria Tzetis
- Laboratory of Medical Genetics, Medical School, National and Kapodistrian University of Athens, St. Sophia's Children's Hospital, Athens, Greece
| | - Roser Pons
- First Department of Pediatrics, Medical School, National and Kapodistrian University of Athens, St. Sophia's Children's Hospital, Athens, Greece
| | - Joanne Traeger-Synodinos
- Laboratory of Medical Genetics, Medical School, National and Kapodistrian University of Athens, St. Sophia's Children's Hospital, Athens, Greece
| | - Christalena Sofocleous
- Laboratory of Medical Genetics, Medical School, National and Kapodistrian University of Athens, St. Sophia's Children's Hospital, Athens, Greece
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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: 12] [Impact Index Per Article: 6.0] [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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Inherited Developmental and Epileptic Encephalopathies. Neurol Int 2021; 13:555-568. [PMID: 34842787 PMCID: PMC8628919 DOI: 10.3390/neurolint13040055] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 10/29/2021] [Accepted: 11/02/2021] [Indexed: 01/13/2023] Open
Abstract
Epileptic encephalopathies often have a genetic etiology. The epileptic activity itself exerts a direct detrimental effect on neurodevelopment, which may add to the cognitive impairment induced by the underlying mutation (“developmental and epileptic encephalopathy”). The focus of this review is on inherited syndromes. The phenotypes of genetic disorders affecting ion channels, metabolic signalling, membrane trafficking and exocytosis, cell adhesion, cell growth and proliferation are discussed. Red flags suggesting family of genes or even specific genes are highlighted. The knowledge of the phenotypical spectrum can indeed prompt the clinician to suspect specific etiologies, expediting the diagnosis.
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Malik I, Kelley CP, Wang ET, Todd PK. Molecular mechanisms underlying nucleotide repeat expansion disorders. Nat Rev Mol Cell Biol 2021; 22:589-607. [PMID: 34140671 PMCID: PMC9612635 DOI: 10.1038/s41580-021-00382-6] [Citation(s) in RCA: 141] [Impact Index Per Article: 47.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/30/2021] [Indexed: 02/05/2023]
Abstract
The human genome contains over one million short tandem repeats. Expansion of a subset of these repeat tracts underlies over fifty human disorders, including common genetic causes of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (C9orf72), polyglutamine-associated ataxias and Huntington disease, myotonic dystrophy, and intellectual disability disorders such as Fragile X syndrome. In this Review, we discuss the four major mechanisms by which expansion of short tandem repeats causes disease: loss of function through transcription repression, RNA-mediated gain of function through gelation and sequestration of RNA-binding proteins, gain of function of canonically translated repeat-harbouring proteins, and repeat-associated non-AUG translation of toxic repeat peptides. Somatic repeat instability amplifies these mechanisms and influences both disease age of onset and tissue specificity of pathogenic features. We focus on the crosstalk between these disease mechanisms, and argue that they often synergize to drive pathogenesis. We also discuss the emerging native functions of repeat elements and how their dynamics might contribute to disease at a larger scale than currently appreciated. Lastly, we propose that lynchpins tying these disease mechanisms and native functions together offer promising therapeutic targets with potential shared applications across this class of human disorders.
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Affiliation(s)
- Indranil Malik
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Chase P Kelley
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics, Genetics Institute, University of Florida, Gainesville, FL, USA
- Genetics and Genomics Graduate Program, University of Florida, Gainesville, FL, USA
| | - Eric T Wang
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics, Genetics Institute, University of Florida, Gainesville, FL, USA.
| | - Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA.
- VA Ann Arbor Healthcare System, Ann Arbor, MI, USA.
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Basa M, Vukovic R, Sarajlija A, Milenkovic T, Djordjevic M, Vucetic B, Martic J. Ambiguous Genitalia and Lissencephaly in A 46,XY Neonate with a Novel Variant of Aristaless Gene. ACTA ENDOCRINOLOGICA (BUCHAREST, ROMANIA : 2005) 2021; 17:402-405. [PMID: 35342471 PMCID: PMC8919491 DOI: 10.4183/aeb.2021.402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
INTRODUCTION Disorders of sexual development can present isolated or as a part of complex genetic syndromes. CASE PRESENTATION A newborn with ambiguous genitalia and prenatally diagnosed brain malformations was referred to our hospital. Prenatal ultrasound examination and MRI showed lissencephaly and absence of the corpus callosum. At admission, physical examination revealed microphallus, hypospadia and complete fusion of labioscrotal folds with nonpalpable gonads, normal blood pressure and serum biochemistry. Cortisol level was normal (201 nmol/L), testosterone elevated (14.4 nmol/L), FSH 0.1 IU/L, LH 0.7 IU/L, estradiol 241 pmol/L. Seizures were noted on the 2nd day and the child was started on anticonvulsives. When 17-OHP level results came back elevated (200 nmol/L), ACTH test was performed and the child was started on hydrocortisone and fludrocortisone treatment. Congenital adrenal hyperplasia became unlikely when karyotype result showed normal male karyotype (46, XY, SRY+) with no Mullerian structures seen on ultrasonographic exam. As association of ambiguous genitalia and lissencephaly strongly suggested a mutual genetic background, diagnosis of X-linked lissencephaly with ambiguous genitalia (X-LAG) became apparent. CONCLUSIONS The presented case highlights the importance of looking at the whole clinical picture instead of separate isolated findings with emphasis on patient-centered approach guided by clinical findings and patient history.
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Affiliation(s)
- M. Basa
- “Dr. Vukan Cupic” Institute for Health Protection of Mother and Child of Serbia, Department of Endocrinology, Serbia
- Correspondence to: Mihail Basa MD, “Dr Vukan Cupic” Institute for Health Protection of Mother and Child of Serbia, Radoja Dakica street 6-8, Beograd, 11070, Serbia, E-mail:
| | - R. Vukovic
- “Dr. Vukan Cupic” Institute for Health Protection of Mother and Child of Serbia, Department of Endocrinology, Serbia
- “Dr. Vukan Cupic” Institute for Health Protection of Mother and Child of Serbia, University of Belgrade, School of Medicine Beograd, Serbia
| | - A. Sarajlija
- “Dr. Vukan Cupic” Institute for Health Protection of Mother and Child of Serbia, Department of Clinical Genetics and Inherited Metabolic Diseases, Serbia
- “Dr. Vukan Cupic” Institute for Health Protection of Mother and Child of Serbia, University of Belgrade, School of Medicine Beograd, Serbia
| | - T. Milenkovic
- “Dr. Vukan Cupic” Institute for Health Protection of Mother and Child of Serbia, Department of Endocrinology, Serbia
| | - M. Djordjevic
- “Dr. Vukan Cupic” Institute for Health Protection of Mother and Child of Serbia, Department of Endocrinology, Serbia
- “Dr. Vukan Cupic” Institute for Health Protection of Mother and Child of Serbia, University of Belgrade, School of Medicine Beograd, Serbia
| | - B. Vucetic
- “Dr. Vukan Cupic” Institute for Health Protection of Mother and Child of Serbia, Department of Neurology, Serbia
| | - J. Martic
- “Dr. Vukan Cupic” Institute for Health Protection of Mother and Child of Serbia, Department of Neonatology, Serbia
- “Dr. Vukan Cupic” Institute for Health Protection of Mother and Child of Serbia, University of Belgrade, School of Medicine Beograd, Serbia
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11
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Phenotypic analysis of catastrophic childhood epilepsy genes. Commun Biol 2021; 4:680. [PMID: 34083748 PMCID: PMC8175701 DOI: 10.1038/s42003-021-02221-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 05/17/2021] [Indexed: 01/06/2023] Open
Abstract
Genetic engineering techniques have contributed to the now widespread use of zebrafish to investigate gene function, but zebrafish-based human disease studies, and particularly for neurological disorders, are limited. Here we used CRISPR-Cas9 to generate 40 single-gene mutant zebrafish lines representing catastrophic childhood epilepsies. We evaluated larval phenotypes using electrophysiological, behavioral, neuro-anatomical, survival and pharmacological assays. Local field potential recordings (LFP) were used to screen ∼3300 larvae. Phenotypes with unprovoked electrographic seizure activity (i.e., epilepsy) were identified in zebrafish lines for 8 genes; ARX, EEF1A, GABRB3, GRIN1, PNPO, SCN1A, STRADA and STXBP1. We also created an open-source database containing sequencing information, survival curves, behavioral profiles and representative electrophysiology data. We offer all zebrafish lines as a resource to the neuroscience community and envision them as a starting point for further functional analysis and/or identification of new therapies. Griffin et al used CRISPR-Cas9 to generate 40 single-gene mutant zebrafish lines representing childhood epilepsies for which they evaluated larval phenotypes using electrophysiological, behavioral, neuro-anatomical, survival and pharmacological assays. Their study provides a useful resource for the future functional analysis and/or identification of potential anti-epileptic therapies.
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12
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Identification and validation of the phosphorylation sites on Aristaless-related homeobox protein. Biosci Rep 2021; 40:225651. [PMID: 32608477 PMCID: PMC7364481 DOI: 10.1042/bsr20194513] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 06/21/2020] [Accepted: 06/29/2020] [Indexed: 11/17/2022] Open
Abstract
The Aristaless-related homeobox protein (ARX) is a transcription factor expressed in the developing forebrain, skeletal muscle, pancreas, testis, and a variety of other tissues. It is known to have context-dependent transcriptional activator and repressor activity, although how it can achieve these opposing functions remains poorly understood. We hypothesized phosphorylation status might play a role in pivoting ARX between functioning as an activator or repressor. To gain further mechanistic insight as to how ARX functions, we identified multiple phosphorylation sites on ARX. We further established PKA as the kinase that phosphorylates ARX at least at Ser266 in mice. Two other kinases, CK2α and CDK4/cyclin D1, were also identified as kinases that phosphorylate ARX in vitro. Unexpectedly, phosphorylation status did not change either the nuclear localization or transcriptional function of ARX.
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13
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Lefebvre M, Bruel AL, Tisserant E, Bourgon N, Duffourd Y, Collardeau-Frachon S, Attie-Bitach T, Kuentz P, Assoum M, Schaefer E, El Chehadeh S, Antal MC, Kremer V, Girard-Lemaitre F, Mandel JL, Lehalle D, Nambot S, Jean-Marçais N, Houcinat N, Moutton S, Marle N, Lambert L, Jonveaux P, Foliguet B, Mazutti JP, Gaillard D, Alanio E, Poirisier C, Lebre AS, Aubert-Lenoir M, Arbez-Gindre F, Odent S, Quélin C, Loget P, Fradin M, Willems M, Bigi N, Perez MJ, Blesson S, Francannet C, Beaufrere AM, Patrier-Sallebert S, Guerrot AM, Goldenberg A, Brehin AC, Lespinasse J, Touraine R, Capri Y, Saint-Frison MH, Laurent N, Philippe C, Tran Mau-Them F, Thevenon J, Faivre L, Thauvin-Robinet C, Vitobello A. Genotype-first in a cohort of 95 fetuses with multiple congenital abnormalities: when exome sequencing reveals unexpected fetal phenotype-genotype correlations. J Med Genet 2020; 58:400-413. [PMID: 32732226 DOI: 10.1136/jmedgenet-2020-106867] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 05/04/2020] [Accepted: 05/21/2020] [Indexed: 11/03/2022]
Abstract
PURPOSE Molecular diagnosis based on singleton exome sequencing (sES) is particularly challenging in fetuses with multiple congenital abnormalities (MCA). Indeed, some studies reveal a diagnostic yield of about 20%, far lower than in live birth individuals showing developmental abnormalities (30%), suggesting that standard analyses, based on the correlation between clinical hallmarks described in postnatal syndromic presentations and genotype, may underestimate the impact of the genetic variants identified in fetal analyses. METHODS We performed sES in 95 fetuses with MCA. Blind to phenotype, we applied a genotype-first approach consisting of combined analyses based on variants annotation and bioinformatics predictions followed by reverse phenotyping. Initially applied to OMIM-morbid genes, analyses were then extended to all genes. We complemented our approach by using reverse phenotyping, variant segregation analysis, bibliographic search and data sharing in order to establish the clinical significance of the prioritised variants. RESULTS sES rapidly identified causal variant in 24/95 fetuses (25%), variants of unknown significance in OMIM genes in 8/95 fetuses (8%) and six novel candidate genes in 6/95 fetuses (6%). CONCLUSIONS This method, based on a genotype-first approach followed by reverse phenotyping, shed light on unexpected fetal phenotype-genotype correlations, emphasising the relevance of prenatal studies to reveal extreme clinical presentations associated with well-known Mendelian disorders.
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Affiliation(s)
- Mathilde Lefebvre
- UFR Des Sciences de Santé, INSERM-Université de Bourgogne UMR1231 GAD « Génétique des Anomalies du Développement », FHU-TRANSLAD, Dijon, France.,Laboratoire d'Anatomo-Pathologie, Plateforme de Biologie Hospitalo-Universitaire, CHU de Dijon Bourgogne, Dijon, France
| | - Ange-Line Bruel
- UFR Des Sciences de Santé, INSERM-Université de Bourgogne UMR1231 GAD « Génétique des Anomalies du Développement », FHU-TRANSLAD, Dijon, France.,Unité Fonctionnelle d'Innovation diagnostique des maladies rares, FHU-TRANSLAD, CHU Dijon Bourgogne, Dijon, France
| | - Emilie Tisserant
- UFR Des Sciences de Santé, INSERM-Université de Bourgogne UMR1231 GAD « Génétique des Anomalies du Développement », FHU-TRANSLAD, Dijon, France
| | - Nicolas Bourgon
- UFR Des Sciences de Santé, INSERM-Université de Bourgogne UMR1231 GAD « Génétique des Anomalies du Développement », FHU-TRANSLAD, Dijon, France
| | - Yannis Duffourd
- UFR Des Sciences de Santé, INSERM-Université de Bourgogne UMR1231 GAD « Génétique des Anomalies du Développement », FHU-TRANSLAD, Dijon, France
| | | | - Tania Attie-Bitach
- Laboratoire d'Embryologie et de Génétique des Malformations Congénitales, Hopital Necker, APHP, Paris Cedex 15, France
| | - Paul Kuentz
- UFR Des Sciences de Santé, INSERM-Université de Bourgogne UMR1231 GAD « Génétique des Anomalies du Développement », FHU-TRANSLAD, Dijon, France
| | - Mirna Assoum
- UFR Des Sciences de Santé, INSERM-Université de Bourgogne UMR1231 GAD « Génétique des Anomalies du Développement », FHU-TRANSLAD, Dijon, France
| | - Elise Schaefer
- Service de Génétique Médicale, CHU de Strasbourg, Hôpital de Hautepierre, Strasbourg, France
| | - Salima El Chehadeh
- Service de Génétique Médicale, CHU de Strasbourg, Hôpital de Hautepierre, Strasbourg, France
| | - Maria Cristina Antal
- Service de Fœtopathologie, CHU de Strasbourg, Hôpital de Hautepierre, Strasbourg, France
| | - Valérie Kremer
- Laboratoire de Cytogénétique constitutionnelle et prénatale, CHU de Strasbourg, Strasbourg, France
| | - Françoise Girard-Lemaitre
- Département Médecine translationnelle et neurogénétique, Institut de génétique et de biologie moléculaire et cellulaire, Strasbourg, France
| | - Jean-Louis Mandel
- Département Médecine translationnelle et neurogénétique, Institut de génétique et de biologie moléculaire et cellulaire, Strasbourg, France
| | - Daphne Lehalle
- Centre de Référence Maladies Rares « Anomalies du Développement et Syndrome Malformatifs » de L'Est, Hôpital D'Enfants, FHU-TRANSLAD, CHU Dijon Bourgogne, Dijon, France
| | - Sophie Nambot
- Centre de Référence Maladies Rares « Anomalies du Développement et Syndrome Malformatifs » de L'Est, Hôpital D'Enfants, FHU-TRANSLAD, CHU Dijon Bourgogne, Dijon, France
| | - Nolwenn Jean-Marçais
- Centre de Référence Maladies Rares « Anomalies du Développement et Syndrome Malformatifs » de L'Est, Hôpital D'Enfants, FHU-TRANSLAD, CHU Dijon Bourgogne, Dijon, France
| | - Nada Houcinat
- Centre de Référence Maladies Rares « Anomalies du Développement et Syndrome Malformatifs » de L'Est, Hôpital D'Enfants, FHU-TRANSLAD, CHU Dijon Bourgogne, Dijon, France
| | - Sébastien Moutton
- UFR Des Sciences de Santé, INSERM-Université de Bourgogne UMR1231 GAD « Génétique des Anomalies du Développement », FHU-TRANSLAD, Dijon, France.,Centre de Référence Maladies Rares « Anomalies du Développement et Syndrome Malformatifs » de L'Est, Hôpital D'Enfants, FHU-TRANSLAD, CHU Dijon Bourgogne, Dijon, France
| | - Nathalie Marle
- Laboratoire de Génétique chromosomique et moléculaire, CHU de Dijon Bourgogne, Dijon, France
| | - Laetita Lambert
- UF de Génétique médicale, Maternité régionale, CHU de Nancy, Nancy, France
| | | | - Bernard Foliguet
- Laboratoire de Biologie de la Reproduction et du Développement Maternité de Nancy, CHU de Nancy, Nancy, France
| | - Jean-Pierre Mazutti
- Laboratoire de Biologie de la Reproduction et du Développement Maternité de Nancy, CHU de Nancy, Nancy, France
| | | | | | | | - Anne-Sophie Lebre
- Service de Génétique et Biologie de la Reproduction, CHU de Reims, Reims, France
| | | | | | - Sylvie Odent
- Service de Génétique Clinique, Hôpital Sud, CLAD Ouest, CNRS UMR6290 Génétique et Pathologies du Développement, Université de Rennes, Rennes, France
| | - Chloé Quélin
- Service de Génétique Clinique, Hôpital Sud, CLAD Ouest, CNRS UMR6290 Génétique et Pathologies du Développement, Université de Rennes, Rennes, France.,Service de Fœtopathologie, CHU de Rennes, Rennes, France
| | - Philippe Loget
- Service de Fœtopathologie, CHU de Rennes, Rennes, France
| | - Melanie Fradin
- Service de Génétique Clinique, Hôpital Sud, CLAD Ouest, CNRS UMR6290 Génétique et Pathologies du Développement, Université de Rennes, Rennes, France
| | - Marjolaine Willems
- Equipe Maladies Génétiques de l'Enfant et de l'Adulte, CHU de Montpellier, Montpellier, France
| | - Nicole Bigi
- Service de Fœtopathologie, CHU de Montpellier, Montpellier, France
| | - Marie-José Perez
- Service de Fœtopathologie, CHU de Montpellier, Montpellier, France
| | | | - Christine Francannet
- Service de Génétique médicale, CHU de Clermont-Ferrand, Clermont-Ferrand, France
| | | | | | | | | | | | | | - Renaud Touraine
- Service de Genetique Clinique, C.H.U. De Saint Etienne-Hopital Nord, Saint Etienne Cedex 2, France
| | - Yline Capri
- Service de génétique clinique, Hôpital Robert Debré - APHP, Paris, France
| | | | - Nicole Laurent
- Laboratoire d'Anatomo-Pathologie, Plateforme de Biologie Hospitalo-Universitaire, CHU de Dijon Bourgogne, Dijon, France
| | - Christophe Philippe
- UFR Des Sciences de Santé, INSERM-Université de Bourgogne UMR1231 GAD « Génétique des Anomalies du Développement », FHU-TRANSLAD, Dijon, France.,Unité Fonctionnelle d'Innovation diagnostique des maladies rares, FHU-TRANSLAD, CHU Dijon Bourgogne, Dijon, France
| | - Frederic Tran Mau-Them
- UFR Des Sciences de Santé, INSERM-Université de Bourgogne UMR1231 GAD « Génétique des Anomalies du Développement », FHU-TRANSLAD, Dijon, France.,Unité Fonctionnelle d'Innovation diagnostique des maladies rares, FHU-TRANSLAD, CHU Dijon Bourgogne, Dijon, France
| | - Julien Thevenon
- UFR Des Sciences de Santé, INSERM-Université de Bourgogne UMR1231 GAD « Génétique des Anomalies du Développement », FHU-TRANSLAD, Dijon, France.,Département de Génétique et Procréation, CHU Grenoble Alpes, Université Grenoble Alpes, Grenoble, France
| | - Laurence Faivre
- UFR Des Sciences de Santé, INSERM-Université de Bourgogne UMR1231 GAD « Génétique des Anomalies du Développement », FHU-TRANSLAD, Dijon, France.,Centre de Référence Maladies Rares « Anomalies du Développement et Syndrome Malformatifs » de L'Est, Hôpital D'Enfants, FHU-TRANSLAD, CHU Dijon Bourgogne, Dijon, France
| | - Christel Thauvin-Robinet
- UFR Des Sciences de Santé, INSERM-Université de Bourgogne UMR1231 GAD « Génétique des Anomalies du Développement », FHU-TRANSLAD, Dijon, France .,Unité Fonctionnelle d'Innovation diagnostique des maladies rares, FHU-TRANSLAD, CHU Dijon Bourgogne, Dijon, France.,Centre de Référence Déficiences Intellectuelles de Causes Rares, Hôpital D'Enfants, CHU Dijon Bourgogne, Dijon, France
| | - Antonio Vitobello
- UFR Des Sciences de Santé, INSERM-Université de Bourgogne UMR1231 GAD « Génétique des Anomalies du Développement », FHU-TRANSLAD, Dijon, France .,Unité Fonctionnelle d'Innovation diagnostique des maladies rares, FHU-TRANSLAD, CHU Dijon Bourgogne, Dijon, 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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Aspromonte MC, Bellini M, Gasparini A, Carraro M, Bettella E, Polli R, Cesca F, Bigoni S, Boni S, Carlet O, Negrin S, Mammi I, Milani D, Peron A, Sartori S, Toldo I, Soli F, Turolla L, Stanzial F, Benedicenti F, Marino-Buslje C, Tosatto SCE, Murgia A, Leonardi E. Characterization of intellectual disability and autism comorbidity through gene panel sequencing. Hum Mutat 2019; 40:1346-1363. [PMID: 31209962 DOI: 10.1002/humu.23822] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 05/18/2019] [Accepted: 05/27/2019] [Indexed: 12/22/2022]
Abstract
Intellectual disability (ID) and autism spectrum disorder (ASD) are clinically and genetically heterogeneous diseases. Recent whole exome sequencing studies indicated that genes associated with different neurological diseases are shared across disorders and converge on common functional pathways. Using the Ion Torrent platform, we developed a low-cost next-generation sequencing gene panel that has been transferred into clinical practice, replacing single disease-gene analyses for the early diagnosis of individuals with ID/ASD. The gene panel was designed using an innovative in silico approach based on disease networks and mining data from public resources to score disease-gene associations. We analyzed 150 unrelated individuals with ID and/or ASD and a confident diagnosis has been reached in 26 cases (17%). Likely pathogenic mutations have been identified in another 15 patients, reaching a total diagnostic yield of 27%. Our data also support the pathogenic role of genes recently proposed to be involved in ASD. Although many of the identified variants need further investigation to be considered disease-causing, our results indicate the efficiency of the targeted gene panel on the identification of novel and rare variants in patients with ID and ASD.
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Affiliation(s)
- Maria C Aspromonte
- Molecular Genetics of Neurodevelopment, Department of Woman and Child Health, University of Padova, C.so Stati Uniti, 4, Padova, Italy.,Fondazione Istituto di Ricerca Pediatrica, Città della Speranza, Padova, Italy
| | - Mariagrazia Bellini
- Molecular Genetics of Neurodevelopment, Department of Woman and Child Health, University of Padova, C.so Stati Uniti, 4, Padova, Italy.,Fondazione Istituto di Ricerca Pediatrica, Città della Speranza, Padova, Italy
| | | | - Marco Carraro
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Elisa Bettella
- Molecular Genetics of Neurodevelopment, Department of Woman and Child Health, University of Padova, C.so Stati Uniti, 4, Padova, Italy.,Fondazione Istituto di Ricerca Pediatrica, Città della Speranza, Padova, Italy
| | - Roberta Polli
- Molecular Genetics of Neurodevelopment, Department of Woman and Child Health, University of Padova, C.so Stati Uniti, 4, Padova, Italy.,Fondazione Istituto di Ricerca Pediatrica, Città della Speranza, Padova, Italy
| | - Federica Cesca
- Molecular Genetics of Neurodevelopment, Department of Woman and Child Health, University of Padova, C.so Stati Uniti, 4, Padova, Italy.,Fondazione Istituto di Ricerca Pediatrica, Città della Speranza, Padova, Italy
| | - Stefania Bigoni
- Medical Genetics Unit, Ospedale Universitario S. Anna, Ferrara, Italy
| | - Stefania Boni
- Medical Genetics Unit, San Martino Hospital, Belluno, Italy
| | - Ombretta Carlet
- Epilepsy and Child Neurophysiology Unit, Scientific Institute IRCCS E. Medea, Treviso, Italy
| | - Susanna Negrin
- Epilepsy and Child Neurophysiology Unit, Scientific Institute IRCCS E. Medea, Treviso, Italy
| | - Isabella Mammi
- Medical Genetics Unit, Dolo General Hospital, Venezia, Italy
| | - Donatella Milani
- Pediatric Highly Intensive Care Unit, Department of Pathophysiology and Transplantation, University of Milano, Milan, Italy
| | - Angela Peron
- Child Neuropsychiatry Unit, Epilepsy Center, Department of Health Sciences, Santi Paolo-Carlo Hospital, University of Milano, Milano, Italy.,Division of Medical Genetics, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, Utah
| | - Stefano Sartori
- Paediatric Neurology Unit, Department of Woman and Child Health, University Hospital of Padova, Padova, Italy
| | - Irene Toldo
- Paediatric Neurology Unit, Department of Woman and Child Health, University Hospital of Padova, Padova, Italy
| | - Fiorenza Soli
- Medical Genetics Department, APSS Trento, Trento, Italy
| | - Licia Turolla
- Medical Genetics Unit, Local Health Authority, Treviso, Italy
| | - Franco Stanzial
- Genetic Counseling Service, Department of Pediatrics, Regional Hospital of Bolzano, Bolzano, Italy
| | - Francesco Benedicenti
- Genetic Counseling Service, Department of Pediatrics, Regional Hospital of Bolzano, Bolzano, Italy
| | | | - Silvio C E Tosatto
- Department of Biomedical Sciences, University of Padova, Padova, Italy.,Institute of Neuroscience, National Research Council, Padova, Italy
| | - Alessandra Murgia
- Molecular Genetics of Neurodevelopment, Department of Woman and Child Health, University of Padova, C.so Stati Uniti, 4, Padova, Italy.,Fondazione Istituto di Ricerca Pediatrica, Città della Speranza, Padova, Italy
| | - Emanuela Leonardi
- Molecular Genetics of Neurodevelopment, Department of Woman and Child Health, University of Padova, C.so Stati Uniti, 4, Padova, Italy.,Fondazione Istituto di Ricerca Pediatrica, Città della Speranza, Padova, Italy
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16
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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: 30] [Impact Index Per Article: 6.0] [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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17
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Dubos A, Meziane H, Iacono G, Curie A, Riet F, Martin C, Loaëc N, Birling MC, Selloum M, Normand E, Pavlovic G, Sorg T, Stunnenberg HG, Chelly J, Humeau Y, Friocourt G, Hérault Y. A new mouse model of ARX dup24 recapitulates the patients' behavioral and fine motor alterations. Hum Mol Genet 2019; 27:2138-2153. [PMID: 29659809 PMCID: PMC5985730 DOI: 10.1093/hmg/ddy122] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2017] [Accepted: 03/26/2018] [Indexed: 01/27/2023] Open
Abstract
The 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, among which the most frequent, a 24 bp duplication in the polyalanine tract 2 (c.428_451dup24), gives rise to intellectual disability, fine motor defects with or without epilepsy. To understand the functional consequences of this mutation, we generated a partially humanized mouse model carrying the c.428_451dup24 duplication (Arxdup24/0) that we characterized at the behavior, neurological and molecular level. Arxdup24/0 males presented with hyperactivity, enhanced stereotypies and altered contextual fear memory. In addition, Arxdup24/0 males had fine motor defects with alteration of reaching and grasping abilities. Transcriptome analysis of Arxdup24/0 forebrains at E15.5 showed a down-regulation of genes specific to interneurons and an up-regulation of genes normally not expressed in this cell type, suggesting abnormal interneuron development. Accordingly, interneuron migration was altered in the cortex and striatum between E15.5 and P0 with consequences in adults, illustrated by the defect in the inhibitory/excitatory balance in Arxdup24/0 basolateral amygdala. Altogether, we showed that the c.428_451dup24 mutation disrupts Arx function with a direct consequence on interneuron development, leading to hyperactivity and defects in precise motor movement control and associative memory. Interestingly, we highlighted striking similarities between the mouse phenotype and a cohort of 33 male patients with ARX c.428_451dup24, suggesting that this new mutant mouse line is a good model for understanding the pathophysiology and evaluation of treatment.
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Affiliation(s)
- Aline Dubos
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Université de Strasbourg, 67404 Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U1258, 67404 Illkirch, France.,CELPHEDIA, PHENOMIN, Institut Clinique de la Souris, 67404 Illkirch, France
| | - Hamid Meziane
- CELPHEDIA, PHENOMIN, Institut Clinique de la Souris, 67404 Illkirch, France
| | - Giovanni Iacono
- Department of Molecular Biology, Radboud Institute for Molecular Life Sciences, Radboud University, 6500 HB Nijmegen, The Netherlands
| | - Aurore Curie
- Centre de Référence Déficiences Intellectuelles de Causes Rares, Hôpital Femmes Mères Enfants, Hospices Civils de Lyon, Institut des Sciences Cognitives, CNRS UMR5304, Université Claude Bernard Lyon1, 69675 Bron, France
| | - Fabrice Riet
- CELPHEDIA, PHENOMIN, Institut Clinique de la Souris, 67404 Illkirch, France
| | - Christelle Martin
- Team Synapse in Cognition, Institut Interdisciplinaire de NeuroScience, Centre National de la Recherche Scientifique CNRS UMR5297, Université de Bordeaux, 33077 Bordeaux, France
| | - Nadège Loaëc
- Inserm UMR 1078, Université de Bretagne Occidentale, Faculté de Médecine et des Sciences de la Santé, Etablissement Français du Sang (EFS) Bretagne, CHRU Brest, Hôpital Morvan, Laboratoire de Génétique Moléculaire, 29200 Brest, France
| | | | - Mohammed Selloum
- CELPHEDIA, PHENOMIN, Institut Clinique de la Souris, 67404 Illkirch, France
| | - Elisabeth Normand
- Team Synapse in Cognition, Institut Interdisciplinaire de NeuroScience, Centre National de la Recherche Scientifique CNRS UMR5297, Université de Bordeaux, 33077 Bordeaux, France.,Pole In Vivo, Institut Interdisciplinaire de NeuroScience, Centre National de la Recherche Scientifique CNRS UMR5297, Université de Bordeaux, 33077 Bordeaux, France
| | - Guillaume Pavlovic
- CELPHEDIA, PHENOMIN, Institut Clinique de la Souris, 67404 Illkirch, France
| | - Tania Sorg
- CELPHEDIA, PHENOMIN, Institut Clinique de la Souris, 67404 Illkirch, France
| | - Henk G Stunnenberg
- Department of Molecular Biology, Radboud Institute for Molecular Life Sciences, Radboud University, 6500 HB Nijmegen, The Netherlands
| | - Jamel Chelly
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Université de Strasbourg, 67404 Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U1258, 67404 Illkirch, France.,Service de Diagnostic Génétique, Hôpital Civil de Strasbourg, Hôpitaux Universitaires de Strasbourg, 67091 Strasbourg, France
| | - Yann Humeau
- Team Synapse in Cognition, Institut Interdisciplinaire de NeuroScience, Centre National de la Recherche Scientifique CNRS UMR5297, Université de Bordeaux, 33077 Bordeaux, France
| | - Gaëlle Friocourt
- Inserm UMR 1078, Université de Bretagne Occidentale, Faculté de Médecine et des Sciences de la Santé, Etablissement Français du Sang (EFS) Bretagne, CHRU Brest, Hôpital Morvan, Laboratoire de Génétique Moléculaire, 29200 Brest, France
| | - Yann Hérault
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Université de Strasbourg, 67404 Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U1258, 67404 Illkirch, France.,CELPHEDIA, PHENOMIN, Institut Clinique de la Souris, 67404 Illkirch, 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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Novel de novo variant in EBF3 is likely to impact DNA binding in a patient with a neurodevelopmental disorder and expanded phenotypes: patient report, in silico functional assessment, and review of published cases. Cold Spring Harb Mol Case Stud 2017; 3:a001743. [PMID: 28487885 PMCID: PMC5411688 DOI: 10.1101/mcs.a001743] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Pathogenic variants in EBF3 were recently described in three back-to-back publications in association with a novel neurodevelopmental disorder characterized by intellectual disability, speech delay, ataxia, and facial dysmorphisms. In this report, we describe an additional patient carrying a de novo missense variant in EBF3 (c.487C>T, p.(Arg163Trp)) that falls within a conserved residue in the zinc knuckle motif of the DNA binding domain. Without a solved structure of the DNA binding domain, we generated a homology-based atomic model and performed molecular dynamics simulations for EBF3, which predicted decreased DNA affinity for p.(Arg163Trp) compared with wild-type protein and control variants. These data are in agreement with previous experimental studies of EBF1 showing the paralogous residue is essential for DNA binding. The conservation and experimental evidence existing for EBF1 and in silico modeling and dynamics simulations to validate comparable behavior of multiple variants in EBF3 demonstrates strong support for the pathogenicity of p.(Arg163Trp). We show that our patient presents with phenotypes consistent with previously reported patients harboring EBF3 variants and expands the phenotypic spectrum of this newly identified disorder with the additional feature of a bicornuate uterus.
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21
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Katsarou A, Moshé SL, Galanopoulou AS. INTERNEURONOPATHIES AND THEIR ROLE IN EARLY LIFE EPILEPSIES AND NEURODEVELOPMENTAL DISORDERS. Epilepsia Open 2017; 2:284-306. [PMID: 29062978 PMCID: PMC5650248 DOI: 10.1002/epi4.12062] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/03/2017] [Indexed: 12/22/2022] Open
Abstract
GABAergic interneurons control the neural circuitry and network activity in the brain. The advances in genetics have identified genes that control the development, maturation and integration of GABAergic interneurons and implicated them in the pathogenesis of epileptic encephalopathies or neurodevelopmental disorders. For example, mutations of the Aristaless-Related homeobox X-linked gene (ARX) may result in defective GABAergic interneuronal migration in infants with epileptic encephalopathies like West syndrome (WS), Ohtahara syndrome or X-linked lissencephaly with abnormal genitalia (XLAG). The concept of "interneuronopathy", i.e. impaired development, migration or function of interneurons, has emerged as a possible etiopathogenic mechanism for epileptic encephalopathies. Treatments that enhance GABA levels, may help seizure control but do not necessarily show disease modifying effect. On the other hand, interneuronopathies can be seen in other conditions in which epilepsy may not be the primary manifestation, such as autism. In this review, we plan to outline briefly the current state of knowledge on the origin, development, and migration and integration of GABAergic interneurons, present neurodevelopmental conditions, with or without epilepsy, that have been associated with interneuronopathies and discuss the evidence linking certain types of interneuronal dysfunction with epilepsy and/or cognitive or behavioral deficits.
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Affiliation(s)
- Anna‐Maria Katsarou
- Laboratory of Developmental EpilepsySaul R. Korey Department of NeurologyAlbert Einstein College of MedicineBronxNew YorkU.S.A.
| | - Solomon L. Moshé
- Laboratory of Developmental EpilepsySaul R. Korey Department of NeurologyAlbert Einstein College of MedicineBronxNew YorkU.S.A.
- Dominick P. Purpura Department of NeuroscienceMontefiore/Einstein Epilepsy CenterAlbert Einstein College of MedicineBronxNew YorkU.S.A.
- Department of PediatricsAlbert Einstein College of MedicineBronxNew YorkU.S.A.
| | - Aristea S. Galanopoulou
- Laboratory of Developmental EpilepsySaul R. Korey Department of NeurologyAlbert Einstein College of MedicineBronxNew YorkU.S.A.
- Dominick P. Purpura Department of NeuroscienceMontefiore/Einstein Epilepsy CenterAlbert Einstein College of MedicineBronxNew YorkU.S.A.
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22
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Abstract
Epileptic encephalopathies account for a large proportion of the intractable early-onset epilepsies and are characterized by frequent seizures and poor developmental outcome. The epileptic encephalopathies can be loosely divided into two related groups of named syndromes. The first comprises epilepsies where continuous EEG changes directly result in cognitive and developmental dysfunction. The second includes patients where cognitive impairment is present at seizure onset and is due to the underlying etiology but the epileptic activity may then worsen the cognitive abilities over time. Recent, large-scale exome studies have begun to establish the genetic architecture of the epileptic encephalopathies, resulting in a re-consideration of the boundaries of these named syndromes. The emergence of this genetic architecture has lead to three main pathophysiological concepts to provide a mechanistic framework for these disorders. In this article, we will review the classic syndromes, the most significant genetic findings, and relate both to the pathophysiological understanding of epileptic encephalopathies.
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23
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Tapie A, Pi-Denis N, Souto J, Vomero A, Peluffo G, Boidi M, Ciganda M, Curbelo N, Raggio V, Roche L, Pastro L. A novel mutation in the OAR domain of the ARX gene. Clin Case Rep 2017; 5:170-174. [PMID: 28174645 PMCID: PMC5290510 DOI: 10.1002/ccr3.769] [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] [Received: 03/10/2016] [Revised: 10/11/2016] [Accepted: 11/16/2016] [Indexed: 11/12/2022] Open
Abstract
Mutations in ARX gene should be considered in patients with mental disability or/and epilepsy. It is an X-linked gene that has pleiotropic effects. Here, we report the case of a boy diagnosed with Ohtahara syndrome. We performed the molecular analysis of the gene and identified a new missense mutation.
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Affiliation(s)
- Alejandra Tapie
- Facultad de Medicina Departamento de Genética Universidad de la República Oriental del Uruguay Montevideo Uruguay
| | - Natalia Pi-Denis
- Facultad de Medicina Departamento de Genética Universidad de la República Oriental del Uruguay Montevideo Uruguay
| | - Jorge Souto
- Facultad de Medicina Departamento de Genética Universidad de la República Oriental del Uruguay Montevideo Uruguay
| | - Alejandra Vomero
- Facultad de Medicina Departamento de Pediatría Universidad de la República Oriental del Uruguay Montevideo Uruguay
| | - Gabriel Peluffo
- Facultad de Medicina Departamento de Pediatría Universidad de la República Oriental del Uruguay Montevideo Uruguay
| | - María Boidi
- Facultad de Medicina Departamento de Genética Universidad de la República Oriental del Uruguay Montevideo Uruguay
| | - Martín Ciganda
- Facultad de Ciencias Laboratorio de Interacciones Moleculares Universidad de la República Oriental del Uruguay Montevideo Uruguay
| | - Nicolás Curbelo
- Facultad de Medicina Departamento de Genética Universidad de la República Oriental del Uruguay Montevideo Uruguay
| | - Victor Raggio
- Facultad de Medicina Departamento de Genética Universidad de la República Oriental del Uruguay Montevideo Uruguay
| | - Leda Roche
- Facultad de Medicina Departamento de Genética Universidad de la República Oriental del Uruguay Montevideo Uruguay
| | - Lucía Pastro
- Facultad de Medicina Departamento de Genética Universidad de la República Oriental del Uruguay Montevideo Uruguay; Facultad de Ciencias Laboratorio de Interacciones Moleculares Universidad de la República Oriental del Uruguay Montevideo Uruguay
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24
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Cho IT, Lim Y, Golden JA, Cho G. Aristaless Related Homeobox (ARX) Interacts with β-Catenin, BCL9, and P300 to Regulate Canonical Wnt Signaling. PLoS One 2017; 12:e0170282. [PMID: 28103279 PMCID: PMC5245867 DOI: 10.1371/journal.pone.0170282] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 01/03/2017] [Indexed: 01/09/2023] Open
Abstract
Mutations in the Aristaless Related Homeobox (ARX) gene are associated with a spectrum of structural (lissencephaly) and functional (epilepsy and intellectual disabilities) neurodevelopmental disorders. How mutations in this single transcription factor can result in such a broad range of phenotypes remains poorly understood. We hypothesized that ARX functions through distinct interactions with specific transcription factors/cofactors to regulate unique target genes in different cell types. To identify ARX interacting proteins, we performed an unbiased proteomics screen and identified several components of the Wnt/β-catenin signaling pathway, including β-catenin (CTNNB1), B-cell CLL/lymphoma 9 (BCL9) and leucine rich repeat flightless interacting protein 2 (LRRFIP2), in cortical progenitor cells. Our data show that ARX positively regulates Wnt/ β-catenin signaling and that the C-terminal domain of ARX interacts with the armadillo repeats in β-catenin to promote Wnt/β-catenin signaling. In addition, we found BCL9 and P300 also interact with ARX to modulate Wnt/β-catenin signaling. These data provide new insights into how ARX can uniquely regulate cortical neurogenesis, and connect the function of ARX with Wnt/β-catenin signaling.
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Affiliation(s)
- Il-Taeg Cho
- Department of Pathology, Brigham and Women’s Hospital, Harvard Medical School Boston, Massachusetts, United States of America
| | - Youngshin Lim
- Department of Pathology, Brigham and Women’s Hospital, Harvard Medical School Boston, Massachusetts, United States of America
| | - Jeffrey A. Golden
- Department of Pathology, Brigham and Women’s Hospital, Harvard Medical School Boston, Massachusetts, United States of America
| | - Ginam Cho
- Department of Pathology, Brigham and Women’s Hospital, Harvard Medical School Boston, Massachusetts, United States of America
- * E-mail:
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25
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Marsh ED, Nasrallah MP, Walsh C, Murray KA, Nicole Sunnen C, McCoy A, Golden JA. Developmental interneuron subtype deficits after targeted loss of Arx. BMC Neurosci 2016; 17:35. [PMID: 27287386 PMCID: PMC4902966 DOI: 10.1186/s12868-016-0265-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 06/03/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Aristaless-related homeobox (ARX) is a paired-like homeodomain transcription factor that functions primarily as a transcriptional repressor and has been implicated in neocortical interneuron specification and migration. Given the role interneurons appear to play in numerous human conditions including those associated with ARX mutations, it is essential to understand the consequences of mutations in this gene on neocortical interneurons. Previous studies have examined the effect of germline loss of Arx, or targeted mutations in Arx, on interneuron development. We now present the effect of conditional loss of Arx on interneuron development. RESULTS To further elucidate the role of Arx in forebrain development we performed a series of anatomical and developmental studies to determine the effect of conditional loss of Arx specifically from developing interneurons in the neocortex and hippocampus. Analysis and cell counts were performed from mouse brains using immunohistochemical and in situ hybridization assays at 4 times points across development. Our data indicate that early in development, instead of a loss of ventral precursors, there is a shift of these precursors to more ventral locations, a deficit that persists in the adult nervous system. The result of this developmental shift is a reduced number of interneurons (all subtypes) at early postnatal and later time periods. In addition, we find that X inactivation is stochastic, and occurs at the level of the neural progenitors. CONCLUSION These data provide further support that the role of Arx in interneuron development is to direct appropriate migration of ventral neuronal precursors into the dorsal cortex and that the loss of Arx results in a failure of interneurons to reach the cortex and thus a deficiency in interneurons.
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Affiliation(s)
- Eric D Marsh
- Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, PA, USA. .,Division of Child Neurology, Children's Hospital of Philadelphia, Room 502E, Abramson Research Building, 3615 Civic Center Boulevard, Philadelphia, PA, 19014, USA. .,Department of Neurology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA.
| | - MacLean Pancoast Nasrallah
- Department of Pathology, Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Department of Pathology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Caroline Walsh
- Division of Child Neurology, Children's Hospital of Philadelphia, Room 502E, Abramson Research Building, 3615 Civic Center Boulevard, Philadelphia, PA, 19014, USA
| | - Kaitlin A Murray
- Division of Child Neurology, Children's Hospital of Philadelphia, Room 502E, Abramson Research Building, 3615 Civic Center Boulevard, Philadelphia, PA, 19014, USA
| | - C Nicole Sunnen
- Department of Pathology, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Almedia McCoy
- Division of Child Neurology, Children's Hospital of Philadelphia, Room 502E, Abramson Research Building, 3615 Civic Center Boulevard, Philadelphia, PA, 19014, USA
| | - Jeffrey A Golden
- Department of Pathology, Children's Hospital of Philadelphia, Philadelphia, PA, USA. .,Department of Pathology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA. .,Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis St., Boston, MA, 02115, USA.
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26
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Jiang X, Lachance M, Rossignol E. Involvement of cortical fast-spiking parvalbumin-positive basket cells in epilepsy. PROGRESS IN BRAIN RESEARCH 2016; 226:81-126. [PMID: 27323940 DOI: 10.1016/bs.pbr.2016.04.012] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
GABAergic interneurons of the parvalbumin-positive fast-spiking basket cells subtype (PV INs) are important regulators of cortical network excitability and of gamma oscillations, involved in signal processing and cognition. Impaired development or function of PV INs has been associated with epilepsy in various animal models of epilepsy, as well as in some genetic forms of epilepsy in humans. In this review, we provide an overview of some of the experimental data linking PV INs dysfunction with epilepsy, focusing on disorders of the specification, migration, maturation, synaptic function, or connectivity of PV INs. Furthermore, we reflect on the potential therapeutic use of cell-type specific stimulation of PV INs within active networks and on the transplantation of PV INs precursors in the treatment of epilepsy and its comorbidities.
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Affiliation(s)
- X Jiang
- Université de Montréal, Montréal, QC, Canada; CHU Ste-Justine Research Center, Montréal, QC, Canada
| | - M Lachance
- CHU Ste-Justine Research Center, Montréal, QC, Canada
| | - E Rossignol
- Université de Montréal, Montréal, QC, Canada; CHU Ste-Justine Research Center, Montréal, QC, Canada.
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27
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Galanopoulou AS, Moshé SL. Neonatal and Infantile Epilepsy: Acquired and Genetic Models. Cold Spring Harb Perspect Med 2015; 6:a022707. [PMID: 26637437 DOI: 10.1101/cshperspect.a022707] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The incidence of seizures and epilepsies is particularly high during the neonatal and infantile periods. We will review selected animal models of early-life epileptic encephalopathies that have addressed the dyscognitive features of frequent interictal spikes, the pathogenesis and treatments of infantile spasms (IS) or Dravet syndrome, disorders with mammalian target of rapamycin (mTOR) dysregulation, and selected early-life epilepsies with genetic defects. Potentially pathogenic mechanisms in these conditions include interneuronopathies in IS or Dravet syndrome and mTOR dysregulation in brain malformations, tuberous sclerosis, and related genetic disorders, or IS of acquired etiology. These models start to generate the first therapeutic drugs, which have been specifically developed in immature animals. However, there are challenges in translating preclinical discoveries into clinically relevant findings. The advances made so far hold promise that the new insights may potentially have curative or disease-modifying potential for many of these devastating conditions.
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Affiliation(s)
- Aristea S Galanopoulou
- Saul R. Korey Department of Neurology, Dominick P. Purpura Department of Neuroscience, Laboratory of Developmental Epilepsy, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Solomon L Moshé
- Saul R. Korey Department of Neurology, Dominick P. Purpura Department of Neuroscience, Laboratory of Developmental Epilepsy, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York 10461 Department of Pediatrics, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York 10461
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28
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Kawauchi T. Cellullar insights into cerebral cortical development: focusing on the locomotion mode of neuronal migration. Front Cell Neurosci 2015; 9:394. [PMID: 26500496 PMCID: PMC4595654 DOI: 10.3389/fncel.2015.00394] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 09/22/2015] [Indexed: 02/01/2023] Open
Abstract
The mammalian brain consists of numerous compartments that are closely connected with each other via neural networks, comprising the basis of higher order brain functions. The highly specialized structure originates from simple pseudostratified neuroepithelium-derived neural progenitors located near the ventricle. A long journey by neurons from the ventricular side is essential for the formation of a sophisticated brain structure, including a mammalian-specific six-layered cerebral cortex. Neuronal migration consists of several contiguous steps, but the locomotion mode comprises a large part of the migration. The locomoting neurons exhibit unique features; a radial glial fiber-dependent migration requiring the endocytic recycling of N-cadherin and a neuron-specific migration mode with dilation/swelling formation that requires the actin and microtubule organization possibly regulated by cyclin-dependent kinase 5 (Cdk5), Dcx, p27(kip1), Rac1, and POSH. Here I will introduce the roles of various cellular events, such as cytoskeletal organization, cell adhesion, and membrane trafficking, in the regulation of the neuronal migration, with particular focus on the locomotion mode.
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Affiliation(s)
- Takeshi Kawauchi
- Department of Physiology, Keio University School of Medicine Tokyo, Japan ; Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency Saitama, Japan ; Laboratory of Molecular Life Science, Institute of Biomedical Research and Innovation, Foundation for Biomedical Research and Innovation Kobe, Japan
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29
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Galanopoulou AS, Moshé SL. Pathogenesis and new candidate treatments for infantile spasms and early life epileptic encephalopathies: A view from preclinical studies. Neurobiol Dis 2015; 79:135-49. [PMID: 25968935 DOI: 10.1016/j.nbd.2015.04.015] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 04/23/2015] [Accepted: 04/30/2015] [Indexed: 12/26/2022] Open
Abstract
Early onset and infantile epileptic encephalopathies (EIEEs) are usually associated with medically intractable or difficult to treat epileptic seizures and prominent cognitive, neurodevelopmental and behavioral consequences. EIEEs have numerous etiologies that contribute to the inter- and intra-syndromic phenotypic variability. Etiologies include structural and metabolic or genetic etiologies although a significant percentage is of unknown cause. The need to better understand their pathogenic mechanisms and identify better therapies has driven the development of animal models of EIEEs. Several rodent models of infantile spasms have emerged that recapitulate various aspects of the disease. The acute models manifest epileptic spasms after induction and include the NMDA rat model, the NMDA model with prior prenatal betamethasone or perinatal stress exposure, and the γ-butyrolactone induced spasms in a mouse model of Down syndrome. The chronic models include the tetrodotoxin rat model, the aristaless related homeobox X-linked (Arx) mouse models and the multiple-hit rat model of infantile spasms. We will discuss the main features and findings from these models on target mechanisms and emerging therapies. Genetic models have also provided interesting data on the pathogenesis of Dravet syndrome and proposed new therapies for testing. The genetic associations of many of the EIEEs have also been tested in rodent models as to their pathogenicity. Finally, several models have tested the impact of subclinical epileptiform discharges on brain function. The impact of these advances in animal modeling for therapy development will be discussed.
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Affiliation(s)
- Aristea S Galanopoulou
- Saul R. Korey Department of Neurology, Dominick P. Purpura Department of Neuroscience, Laboratory of Developmental Epilepsy, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY, USA.
| | - Solomon L Moshé
- Saul R. Korey Department of Neurology, Dominick P. Purpura Department of Neuroscience, Laboratory of Developmental Epilepsy, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY, USA; Department of Pediatrics, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY, USA.
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Kwong AKY, Ho ACC, Fung CW, Wong VCN. Analysis of mutations in 7 genes associated with neuronal excitability and synaptic transmission in a cohort of children with non-syndromic infantile epileptic encephalopathy. PLoS One 2015; 10:e0126446. [PMID: 25951140 PMCID: PMC4423861 DOI: 10.1371/journal.pone.0126446] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 04/02/2015] [Indexed: 11/23/2022] Open
Abstract
Epileptic Encephalopathy (EE) is a heterogeneous condition in which cognitive, sensory and/or motor functions deteriorate as a consequence of epileptic activity, which consists of frequent seizures and/or major interictal paroxysmal activity. There are various causes of EE and they may occur at any age in early childhood. Genetic mutations have been identified to contribute to an increasing number of children with early onset EE which had been previously considered as cryptogenic. We identified 26 patients with Infantile Epileptic Encephalopathy (IEE) of unknown etiology despite extensive workup and without any specific epilepsy syndromic phenotypes. We performed genetic analysis on a panel of 7 genes (ARX, CDKL5, KCNQ2, PCDH19, SCN1A, SCN2A, STXBP1) and identified 10 point mutations [ARX (1), CDKL5 (3), KCNQ2 (2), PCDH19 (1), SCN1A (1), STXBP1 (2)] as well as one microdeletion involving both SCN1A and SCN2A. The high rate (42%) of mutations suggested that genetic testing of this IEE panel of genes is recommended for cryptogenic IEE with no etiology identified. These 7 genes are associated with channelopathies or synaptic transmission and we recommend early genetic testing if possible to guide the treatment strategy.
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Affiliation(s)
- Anna Ka-Yee Kwong
- Division of Paediatric Neurology / Developmental Behavioural Paediatrics / Neurohabilitation, Department of Paediatrics and Adolescent Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Alvin Chi-Chung Ho
- Division of Paediatric Neurology / Developmental Behavioural Paediatrics / Neurohabilitation, Department of Paediatrics and Adolescent Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Cheuk-Wing Fung
- Division of Paediatric Neurology / Developmental Behavioural Paediatrics / Neurohabilitation, Department of Paediatrics and Adolescent Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Virginia Chun-Nei Wong
- Division of Paediatric Neurology / Developmental Behavioural Paediatrics / Neurohabilitation, Department of Paediatrics and Adolescent Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
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Nord AS, Pattabiraman K, Visel A, Rubenstein JLR. Genomic perspectives of transcriptional regulation in forebrain development. Neuron 2015; 85:27-47. [PMID: 25569346 PMCID: PMC4438709 DOI: 10.1016/j.neuron.2014.11.011] [Citation(s) in RCA: 106] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The forebrain is the seat of higher-order brain functions, and many human neuropsychiatric disorders are due to genetic defects affecting forebrain development, making it imperative to understand the underlying genetic circuitry. Recent progress now makes it possible to begin fully elucidating the genomic regulatory mechanisms that control forebrain gene expression. Herein, we discuss the current knowledge of how transcription factors drive gene expression programs through their interactions with cis-acting genomic elements, such as enhancers; how analyses of chromatin and DNA modifications provide insights into gene expression states; and how these approaches yield insights into the evolution of the human brain.
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Affiliation(s)
- Alex S Nord
- Department of Neurobiology, Physiology, and Behavior and Department of Psychiatry and Behavioral Sciences, Center for Neuroscience, University of California, Davis, Davis, CA 95618, USA.
| | - Kartik Pattabiraman
- Department of Psychiatry, Rock Hall, University of California, San Francisco, San Francisco, CA 94158-2324, USA
| | - Axel Visel
- Genomics Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; US Department of Energy Joint Genome Institute, Walnut Creek, CA 94598, USA; School of Natural Sciences, University of California, Merced, Merced, CA 95343, USA
| | - John L R Rubenstein
- Department of Psychiatry, Rock Hall, University of California, San Francisco, San Francisco, CA 94158-2324, USA
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Ngoh A, McTague A, Wentzensen IM, Meyer E, Applegate C, Kossoff EH, Batista DA, Wang T, Kurian MA. Severe infantile epileptic encephalopathy due to mutations in PLCB1: expansion of the genotypic and phenotypic disease spectrum. Dev Med Child Neurol 2014; 56:1124-8. [PMID: 24684524 PMCID: PMC4230412 DOI: 10.1111/dmcn.12450] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/06/2014] [Indexed: 11/28/2022]
Abstract
Homozygous deletions of chromosome 20p12.3, disrupting the promoter region and first three coding exons of the phospholipase C β1 gene (PLCB1), have previously been described in two reports of early infantile epileptic encephalopathy (EIEE). Both children were born to consanguineous parents, one presented with infantile spasms, the other with migrating partial seizures of infancy. We describe an infant presenting with severe intractable epilepsy (without a specific EIEE electroclinical syndrome diagnosis) and neurodevelopmental delay associated with compound heterozygous mutations in PLCB1. A case note review and molecular genetic investigations were performed for a child, approximately 10 months of age, admitted to Johns Hopkins University Hospital for developmental delay and new-onset seizures. The patient presented at 6 months of age with developmental delay, followed by the onset of intractable, focal, and generalized seizures associated with developmental regression from 10 months of age. Presently, at 2 years of age, the child has severe motor and cognitive delays. Diagnostic microarray revealed a heterozygous 476kb deletion of 20p12.3 (encompassing PLCB1), which was also detected in the mother. The genomic breakpoints for the heterozygous deletion were determined. In order to investigate the presence of a second PLCB1 mutation, direct Sanger sequencing of the coding region and flanking intronic regions was undertaken, revealing a novel heterozygous intron 1 splice site variant (c.99+1G>A) in both the index individual and the father. Advances in molecular genetic testing have greatly improved diagnostic rates in EIEE, and this report further confirms the important role of microarray investigation in this group of disorders. PLCB1-EIEE is now reported in a number of different EIEE phenotypes and our report provides further evidence for phenotypic pleiotropy encountered in early infantile epilepsy syndromes.
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Affiliation(s)
- Adeline Ngoh
- Neurosciences Unit, Developmental Neurosciences, University College London, Institute of Child HealthLondon, UK,Department of Neurology, Great Ormond Street HospitalLondon, UK
| | - Amy McTague
- Neurosciences Unit, Developmental Neurosciences, University College London, Institute of Child HealthLondon, UK,Department of Neurology, Great Ormond Street HospitalLondon, UK
| | - Ingrid M Wentzensen
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of MedicineBaltimore, MD, USA
| | - Esther Meyer
- Neurosciences Unit, Developmental Neurosciences, University College London, Institute of Child HealthLondon, UK
| | - Carolyn Applegate
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of MedicineBaltimore, MD, USA
| | - Eric H Kossoff
- Department of Pediatrics, Johns Hopkins University School of MedicineBaltimore, MD, USA,Department of Neurology, Johns Hopkins University School of MedicineBaltimore, MD, USA
| | - Denise A Batista
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of MedicineBaltimore, MD, USA,Department of Pathology, Johns Hopkins University School of MedicineBaltimore, MD, USA,Kennedy Krieger InstituteBaltimore, MD, USA
| | - Tao Wang
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of MedicineBaltimore, MD, USA,Department of Pediatrics, Johns Hopkins University School of MedicineBaltimore, MD, USA
| | - Manju A Kurian
- Neurosciences Unit, Developmental Neurosciences, University College London, Institute of Child HealthLondon, UK,Department of Neurology, Great Ormond Street HospitalLondon, UK
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Bourgeois EB, Johnson BN, McCoy AJ, Trippa L, Cohen AS, Marsh ED. A toolbox for spatiotemporal analysis of voltage-sensitive dye imaging data in brain slices. PLoS One 2014; 9:e108686. [PMID: 25259520 PMCID: PMC4178182 DOI: 10.1371/journal.pone.0108686] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 09/02/2014] [Indexed: 12/30/2022] Open
Abstract
Voltage-sensitive dye imaging (VSDI) can simultaneously monitor the spatiotemporal electrical dynamics of thousands of neurons and is often used to identify functional differences in models of neurological disease. While the chief advantage of VSDI is the ability to record spatiotemporal activity, there are no tools available to visualize and statistically compare activity across the full spatiotemporal range of the VSDI dataset. Investigators commonly analyze only a subset of the data, and a majority of the dataset is routinely excluded from analysis. We have developed a software toolbox that simplifies visual inspection of VSDI data, and permits unaided statistical comparison across spatial and temporal dimensions. First, the three-dimensional VSDI dataset (x,y,time) is geometrically transformed into a two-dimensional spatiotemporal map of activity. Second, statistical comparison between groups is performed using a non-parametric permutation test. The result is a 2D map of all significant differences in both space and time. Here, we used the toolbox to identify functional differences in activity in VSDI data from acute hippocampal slices obtained from epileptic Arx conditional knock-out and control mice. Maps of spatiotemporal activity were produced and analyzed to identify differences in the activity evoked by stimulation of each of two axonal inputs to the hippocampus: the perforant pathway and the temporoammonic pathway. In mutant hippocampal slices, the toolbox identified a widespread decrease in spatiotemporal activity evoked by the temporoammonic pathway. No significant differences were observed in the activity evoked by the perforant pathway. The VSDI toolbox permitted us to visualize and statistically compare activity across the spatiotemporal scope of the VSDI dataset. Sampling error was minimized because the representation of the data is standardized by the toolbox. Statistical comparisons were conducted quickly, across the spatiotemporal scope of the data, without a priori knowledge of the character of the responses or the likely differences between them.
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Affiliation(s)
- Elliot B. Bourgeois
- Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
| | - Brian N. Johnson
- Department of Pediatrics, Division of Pediatric Neurology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Almedia J. McCoy
- Department of Pediatrics, Division of Pediatric Neurology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Lorenzo Trippa
- Department of Biostatistics and Computational Biology, Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
| | - Akiva S. Cohen
- Department of Pediatrics, Division of Pediatric Neurology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
- Department of Neurology, Division of Pediatric Neurology, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Eric D. Marsh
- Department of Pediatrics, Division of Pediatric Neurology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
- Department of Neurology, Division of Pediatric Neurology, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
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Cho G, Lim Y, Cho IT, Simonet JC, Golden JA. Arx together with FoxA2, regulates Shh floor plate expression. Dev Biol 2014; 393:137-48. [PMID: 24968361 DOI: 10.1016/j.ydbio.2014.06.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 06/11/2014] [Accepted: 06/12/2014] [Indexed: 11/16/2022]
Abstract
Mutations in the Aristaless related homeodomain transcription factor (ARX) are associated with a diverse set of X-linked mental retardation and epilepsy syndromes in humans. Although most studies have been focused on its function in the forebrain, ARX is also expressed in other regions of the developing nervous system including the floor plate (FP) of the spinal cord where its function is incompletely understood. To investigate the role of Arx in the FP, we performed gain-of-function studies in the chick using in ovo electroporation, and loss-of-function studies in Arx-deficient mice. We have found that Arx, in conjunction with FoxA2, directly induces Sonic hedgehog (Shh) expression through binding to a Shh floor plate enhancer (SFPE2). We also observed that FoxA2 induces Arx through its transcriptional activation domain whereas Nkx2.2, induced by Shh, abolishes this induction. Our data support a feedback loop model for Arx function; through interactions with FoxA2, Arx positively regulates Shh expression in the FP, and Shh signaling in turn activates Nkx2.2, which suppresses Arx expression. Furthermore, our data are evidence that Arx plays a role as a context dependent transcriptional activator, rather than a primary inducer of Shh expression, potentially explaining how mutations in ARX are associated with diverse, and often subtle, defects.
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Affiliation(s)
- Ginam Cho
- Department of Pathology, Brigham and Women׳s Hospital, Harvard Medical School, USA; Department of Pathology and Laboratory Medicine, Children׳s Hospital of Philadelphia, USA
| | - Youngshin Lim
- Department of Pathology, Brigham and Women׳s Hospital, Harvard Medical School, USA
| | - Il-Taeg Cho
- Department of Pathology, Brigham and Women׳s Hospital, Harvard Medical School, USA
| | - Jacqueline C Simonet
- Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, USA
| | - Jeffrey A Golden
- Department of Pathology, Brigham and Women׳s Hospital, Harvard Medical School, USA; Department of Pathology and Laboratory Medicine, Children׳s Hospital of Philadelphia, USA.
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Pardo CA, Nabbout R, Galanopoulou AS. Mechanisms of epileptogenesis in pediatric epileptic syndromes: Rasmussen encephalitis, infantile spasms, and febrile infection-related epilepsy syndrome (FIRES). Neurotherapeutics 2014; 11:297-310. [PMID: 24639375 PMCID: PMC3996116 DOI: 10.1007/s13311-014-0265-2] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The mechanisms of epileptogenesis in pediatric epileptic syndromes are diverse, and may involve disturbances of neurodevelopmental trajectories, synaptic homeostasis, and cortical connectivity, which may occur during brain development, early infancy, or childhood. Although genetic or structural/metabolic factors are frequently associated with age-specific epileptic syndromes, such as infantile spasms and West syndrome, other syndromes may be determined by the effect of immunopathogenic mechanisms or energy-dependent processes in response to environmental challenges, such as infections or fever in normally-developed children during early or late childhood. Immune-mediated mechanisms have been suggested in selected pediatric epileptic syndromes in which acute and rapidly progressive encephalopathies preceded by fever and/or infections, such as febrile infection-related epilepsy syndrome, or in chronic progressive encephalopathies, such as Rasmussen encephalitis. A definite involvement of adaptive and innate immune mechanisms driven by cytotoxic CD8(+) T lymphocytes and neuroglial responses has been demonstrated in Rasmussen encephalitis, although the triggering factor of these responses remains unknown. Although the beneficial response to steroids and adrenocorticotropic hormone of infantile spasms, or preceding fever or infection in FIRES, may support a potential role of neuroinflammation as pathogenic factor, no definite demonstration of such involvement has been achieved, and genetic or metabolic factors are suspected. A major challenge for the future is discovering pathogenic mechanisms and etiological factors that facilitate the introduction of novel targets for drug intervention aimed at interfering with the disease mechanisms, therefore providing putative disease-modifying treatments in these pediatric epileptic syndromes.
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Affiliation(s)
- Carlos A Pardo
- Department of Neurology, Division of Neuroimmunology and Neuroinfectious Disorders, Center for Pediatric Rasmussen Syndrome, Johns Hopkins University School of Medicine, Baltimore, MD, USA,
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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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A modular gain-of-function approach to generate cortical interneuron subtypes from ES cells. Neuron 2014; 80:1145-58. [PMID: 24314726 DOI: 10.1016/j.neuron.2013.09.022] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/11/2013] [Indexed: 01/18/2023]
Abstract
Whereas past work indicates that cortical interneurons (cINs) can be generically produced from stem cells, generating large numbers of specific subtypes of this population has remained elusive. This reflects an information gap in our understanding of the transcriptional programs required for different interneuron subtypes. Here, we have utilized the directed differentiation of stem cells into specific subpopulations of cortical interneurons as a means to identify some of these missing factors. To establish this approach, we utilized two factors known to be required for the generation of cINs, Nkx2-1 and Dlx2. As predicted, their regulated transient expression greatly improved the differentiation efficiency and specificity over baseline. We extended upon this "cIN-primed" model in order to establish a modular system whereby a third transcription factor could be systematically introduced. Using this approach, we identified Lmo3 and Pou3f4 as genes that can augment the differentiation and/or subtype specificity of cINs in vitro.
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Ye W, Lin W, Tartakoff AM, Ma Q, Tao T. Nuclear import of aristaless-related homeobox protein via its NLS1 regulates its transcriptional function. Mol Cell Biochem 2013; 381:221-31. [PMID: 23771350 DOI: 10.1007/s11010-013-1706-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2012] [Accepted: 05/24/2013] [Indexed: 10/26/2022]
Abstract
Nucleocytoplasmic transport of transcription factors is essential in eukaryotes. We previously reported the presence of two functional NLSs in the homeodomain protein, aristaless-related homeobox (Arx) protein, which is a key transcriptional repressor of LMO1, SHOX2, and PAX4 during development. NLS2, that overlaps the homeodomain, is recognized directly by multiple importin βs, but not by importin αs. In this study, we found that the N-terminal NLS1 of Arx is targeted by multiple importin α proteins, including importin α3 and α5. Both in vivo and in vitro assays demonstrated that nuclear import of Arx via NLS1 is mediated by the importin α/β pathway. Mutagenesis analysis indicated that two basic amino acids, (84)K and (87)R, are essential to the function of NLS1, and that their mutation prevents interactions of Arx with importin αs. Interestingly, inhibition of nuclear import of Arx via NLS1 clearly attenuates its ability of transcriptional repression, suggesting that nuclear import of Arx via NLS1 contributes to its transcriptional function.
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Affiliation(s)
- Wenduo Ye
- Xiamen University School of Life Sciences, Xiamen, Fujian, China
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Arber C, Li M. Cortical interneurons from human pluripotent stem cells: prospects for neurological and psychiatric disease. Front Cell Neurosci 2013; 7:10. [PMID: 23493959 PMCID: PMC3595684 DOI: 10.3389/fncel.2013.00010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Accepted: 01/28/2013] [Indexed: 01/20/2023] Open
Abstract
Cortical interneurons represent 20% of the cells in the cortex. These cells are local inhibitory neurons whose function is to modulate the firing activities of the excitatory projection neurons. Cortical interneuron dysfunction is believed to lead to runaway excitation underlying (or implicated in) seizure-based diseases, such as epilepsy, autism, and schizophrenia. The complex development of this cell type and the intricacies involved in defining the relative subtypes are being increasingly well defined. This has led to exciting experimental cell therapy in model organisms, whereby fetal-derived interneuron precursors can reverse seizure severity and reduce mortality in adult epileptic rodents. These proof-of-principle studies raise hope for potential interneuron-based transplantation therapies for treating epilepsy. On the other hand, cortical neurons generated from patient iPSCs serve as a valuable tool to explore genetic influences of interneuron development and function. This is a fundamental step in enhancing our understanding of the molecular basis of neuropsychiatric illnesses and the development of targeted treatments. Protocols are currently being developed for inducing cortical interneuron subtypes from mouse and human pluripotent stem cells. This review sets out to summarize the progress made in cortical interneuron development, fetal tissue transplantation and the recent advance in stem cell differentiation toward interneurons.
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Affiliation(s)
- Charles Arber
- Stem Cell Neurogenesis, MRC Clinical Sciences Centre, Imperial College London London, UK
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Poeta L, Fusco F, Drongitis D, Shoubridge C, Manganelli G, Filosa S, Paciolla M, Courtney M, Collombat P, Lioi M, Gecz J, Ursini M, Miano M. A regulatory path associated with X-linked intellectual disability and epilepsy links KDM5C to the polyalanine expansions in ARX. Am J Hum Genet 2013; 92:114-25. [PMID: 23246292 DOI: 10.1016/j.ajhg.2012.11.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Revised: 06/07/2012] [Accepted: 11/13/2012] [Indexed: 10/27/2022] Open
Abstract
Intellectual disability (ID) and epilepsy often occur together and have a dramatic impact on the development and quality of life of the affected children. Polyalanine (polyA)-expansion-encoding mutations of aristaless-related homeobox (ARX) cause a spectrum of X-linked ID (XLID) diseases and chronic epilepsy, including infantile spasms. We show that lysine-specific demethylase 5C (KDM5C), a gene known to be mutated in XLID-affected children and involved in chromatin remodeling, is directly regulated by ARX through the binding in a conserved noncoding element. We have studied altered ARX carrying various polyA elongations in individuals with XLID and/or epilepsy. The changes in polyA repeats cause hypomorphic ARX alterations, which exhibit a decreased trans-activity and reduced, but not abolished, binding to the KDM5C regulatory region. The altered functioning of the mutants tested is likely to correlate with the severity of XLID and/or epilepsy. By quantitative RT-PCR, we observed a dramatic Kdm5c mRNA downregulation in murine Arx-knockout embryonic and neural stem cells. Such Kdm5c mRNA diminution led to a severe decrease in the KDM5C content during in vitro neuronal differentiation, which inversely correlated with an increase in H3K4me3 signal. We established that ARX polyA alterations damage the regulation of KDM5C expression, and we propose a potential ARX-dependent path acting via chromatin remodeling.
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De novo gain-of-function KCNT1 channel mutations cause malignant migrating partial seizures of infancy. Nat Genet 2012; 44:1255-9. [PMID: 23086397 DOI: 10.1038/ng.2441] [Citation(s) in RCA: 334] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Accepted: 09/17/2012] [Indexed: 12/14/2022]
Abstract
Malignant migrating partial seizures of infancy (MMPSI) is a rare epileptic encephalopathy of infancy that combines pharmacoresistant seizures with developmental delay. We performed exome sequencing in three probands with MMPSI and identified de novo gain-of-function mutations affecting the C-terminal domain of the KCNT1 potassium channel. We sequenced KCNT1 in 9 additional individuals with MMPSI and identified mutations in 4 of them, in total identifying mutations in 6 out of 12 unrelated affected individuals. Functional studies showed that the mutations led to constitutive activation of the channel, mimicking the effects of phosphorylation of the C-terminal domain by protein kinase C. In addition to regulating ion flux, KCNT1 has a non-conducting function, as its C terminus interacts with cytoplasmic proteins involved in developmental signaling pathways. These results provide a focus for future diagnostic approaches and research for this devastating condition.
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Distinct DNA binding and transcriptional repression characteristics related to different ARX mutations. Neurogenetics 2012; 13:23-9. [PMID: 22252899 DOI: 10.1007/s10048-011-0304-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Accepted: 10/31/2011] [Indexed: 01/04/2023]
Abstract
Mutations in the Aristaless-related homeobox gene (ARX) are associated with a wide variety of neurologic disorders including lissencephaly, hydrocephaly, West syndrome, Partington syndrome, and X-linked intellectual disability with or without epilepsy. A genotype-phenotype correlation exists for ARX mutations; however, the molecular basis for this association has not been investigated. To begin understanding the molecular basis for ARX mutations, we tested the DNA binding sequence preference and transcriptional repression activity for Arx, deletion mutants and mutants associated with various neurologic disorders. We found DNA binding preferences of Arx are influenced by the amino acid sequences adjacent to the homeodomain. Mutations in the homeodomain show a loss of DNA binding activity, while the T333N and P353R homeodomain mutants still possess DNA binding activities, although less than the wild type. Transcription repression activity, the primary function of ARX, is reduced in all mutants except the L343Q, which has no DNA binding activity and does not functionally repress Arx targets. These data indicate that mutations in the homeodomain result in not only a loss of DNA binding activity but also loss of transcriptional repression activity. Our results provide novel insights into the pathogenesis of ARX-related disorders and possible directions to pursue potential therapeutic interventions.
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Abstract
Epilepsy is characterized by spontaneous recurrent seizures and comprises a diverse group of syndromes with different etiologies. Epileptogenesis refers to the process whereby the brain becomes epileptic and can be related to several factors, such as acquired structural brain lesions, inborn brain malformations, alterations in neuronal signaling, and defects in maturation and plasticity of neuronal networks. In this review, we will focus on alterations of brain development that lead to an hyperexcitability phenotype in adulthood, providing examples from both animal and human studies. Malformations of cortical development (including focal cortical dysplasia, lissencephaly, heterotopia, and polymicrogyria) are frequently epileptogenic and result from defects in cell proliferation in the germinal zone and/or impaired neuronal migration and differentiation. Delayed or reduced arrival of inhibitory interneurons into the cortical plate is another possible cause of epileptogenesis. GABAergic neurons are generated during early development in the ganglionic eminences, and failure to pursue migration toward the cortex alters the excitatory/inhibitory balance resulting in aberrant network hyperexcitability. More subtle defects in the developmental assembly of excitatory and inhibitory synapses are also involved in epilepsy. For example, mutations in the presynaptic proteins synapsins and SNAP-25 cause derangements of synaptic transmission and plasticity which underlie appearance of an epileptic phenotype. Finally, there is evidence that defects in synapse elimination and remodeling during early "critical periods" can trigger hyperexcitability later in life. Further clarification of the developmental pathways to epilepsy has important implications for disease prevention and therapy.
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Affiliation(s)
- Yuri Bozzi
- Laboratory of Molecular Neuropathology, Centre for Integrative Biology, University of Trento Trento, Italy
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Friocourt G, Parnavelas JG. Identification of Arx targets unveils new candidates for controlling cortical interneuron migration and differentiation. Front Cell Neurosci 2011; 5:28. [PMID: 22355284 PMCID: PMC3280452 DOI: 10.3389/fncel.2011.00028] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Accepted: 12/08/2011] [Indexed: 11/13/2022] Open
Abstract
Mutations in the homeobox transcription factor ARX have been found to be responsible for a wide spectrum of disorders extending from phenotypes with severe neuronal migration defects, such as lissencephaly, to mild forms of intellectual disabilities without apparent brain abnormalities, but with associated features of dystonia and epilepsy. Arx expression is mainly restricted to populations of GABA-containing neurons. Studies of the effects of ARX loss of function, either in humans or mutant mice, revealed varying defects, suggesting multiple roles of this gene in brain patterning, neuronal proliferation and migration, cell maturation and differentiation, as well as axonal outgrowth and connectivity. However, to date, little is known about how Arx functions as a transcription factor or which genes it binds and regulates. Recently, we combined chromatin immunoprecipitation and mRNA expression with microarray analysis and identified approximately 1000 gene promoters bound by Arx in transfected neuroblastoma N2a cells and mouse embryonic brain. To narrow the analysis of Arx targets to those most likely to control cortical interneuron migration and/or differentiation, we compare here our data to previously published studies searching for genes enriched or down-regulated in cortical interneurons between E13.5 and E15.5. We thus identified 14 Arx-target genes enriched (Cxcr7, Meis1, Ppap2a, Slc 12a5, Ets2, Phlda1, Egr1, Igf1, Lmo3, Sema6, Lgi1, Alk, Tgfb3, and Napb) and 5 genes specifically down-regulated (Hmgn3, Lmo1, Ebf3, Rasgef1b, and Slit2) in cortical migrating neurons. In this review, we present these genes and discuss how their possible regulation by Arx may lead to the dysfunction of GABAergic neurons, resulting in mental retardation and epilepsy.
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Affiliation(s)
- Gaëlle Friocourt
- Laboratory of Molecular Genetics and Histocompatibility Inserm U613, Brest, France
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Nasrallah MP, Cho G, Simonet JC, Putt ME, Kitamura K, Golden JA. Differential effects of a polyalanine tract expansion in Arx on neural development and gene expression. Hum Mol Genet 2011; 21:1090-8. [PMID: 22108177 DOI: 10.1093/hmg/ddr538] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Polyalanine (poly-A) tracts exist in 494 annotated proteins; to date, expansions in these tracts have been associated with nine human diseases. The pathogenetic mechanism by which a poly-A tract results in these various human disorders remains uncertain. To understand the role of this mutation type, we investigated the change in functional properties of the transcription factor Arx when it has an expanded poly-A tract (Arx(E)), a mutation associated with infantile spasms and intellectual disabilities in humans. We found that although Arx(E) functions normally in the dorsal brain, its function in subpallial-derived populations of neurons is compromised. These contrasting functions are associated with the misregulation of Arx targets through the loss of the ability of Arx(E) to interact with the Arx cofactor Tle1. Our data demonstrate a novel mechanism for poly-A expansion diseases: the misregulation of a subset of target genes normally regulated by a transcription factor.
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Genetics and function of neocortical GABAergic interneurons in neurodevelopmental disorders. Neural Plast 2011; 2011:649325. [PMID: 21876820 PMCID: PMC3159129 DOI: 10.1155/2011/649325] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Accepted: 05/04/2011] [Indexed: 12/04/2022] Open
Abstract
A dysfunction of cortical and limbic GABAergic circuits has been postulated to contribute to multiple neurodevelopmental disorders in humans, including schizophrenia, autism, and epilepsy. In the current paper, I summarize the characteristics that underlie the great diversity of cortical GABAergic interneurons and explore how the multiple roles of these cells in developing and mature circuits might contribute to the aforementioned disorders. Furthermore, I review the tightly controlled genetic cascades that determine the fate of cortical interneurons and summarize how the dysfunction of genes important for the generation, specification, maturation, and function of cortical interneurons might contribute to these disorders.
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Altered GABA signaling in early life epilepsies. Neural Plast 2011; 2011:527605. [PMID: 21826277 PMCID: PMC3150203 DOI: 10.1155/2011/527605] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2011] [Revised: 05/04/2011] [Accepted: 05/27/2011] [Indexed: 01/13/2023] Open
Abstract
The incidence of seizures is particularly high in the early ages of life. The immaturity of inhibitory systems, such as GABA, during normal brain development and its further dysregulation under pathological conditions that predispose to seizures have been speculated to play a major role in facilitating seizures. Seizures can further impair or disrupt GABAA signaling by reshuffling the subunit composition of its receptors or causing aberrant reappearance of depolarizing or hyperpolarizing GABAA receptor currents. Such effects may not result in epileptogenesis as frequently as they do in adults. Given the central role of GABAA signaling in brain function and development, perturbation of its physiological role may interfere with neuronal morphology, differentiation, and connectivity, manifesting as cognitive or neurodevelopmental deficits. The current GABAergic antiepileptic drugs, while often effective for adults, are not always capable of stopping seizures and preventing their sequelae in neonates. Recent studies have explored the therapeutic potential of chloride cotransporter inhibitors, such as bumetanide, as adjunctive therapies of neonatal seizures. However, more needs to be known so as to develop therapies capable of stopping seizures while preserving the age- and sex-appropriate development of the brain.
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Role of cytoskeletal abnormalities in the neuropathology and pathophysiology of type I lissencephaly. Acta Neuropathol 2011; 121:149-70. [PMID: 21046408 PMCID: PMC3037170 DOI: 10.1007/s00401-010-0768-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Revised: 10/01/2010] [Accepted: 10/23/2010] [Indexed: 01/24/2023]
Abstract
Type I lissencephaly or agyria-pachygyria is a rare developmental disorder which results from a defect of neuronal migration. It is characterized by the absence of gyri and a thickening of the cerebral cortex and can be associated with other brain and visceral anomalies. Since the discovery of the first genetic cause (deletion of chromosome 17p13.3), six additional genes have been found to be responsible for agyria–pachygyria. In this review, we summarize the current knowledge concerning these genetic disorders including clinical, neuropathological and molecular results. Genetic alterations of LIS1, DCX, ARX, TUBA1A, VLDLR, RELN and more recently WDR62 genes cause migrational abnormalities along with more complex and subtle anomalies affecting cell proliferation and differentiation, i.e., neurite outgrowth, axonal pathfinding, axonal transport, connectivity and even myelination. The number and heterogeneity of clinical, neuropathological and radiological defects suggest that type I lissencephaly now includes several forms of cerebral malformations. In vitro experiments and mutant animal studies, along with neuropathological abnormalities in humans are of invaluable interest for the understanding of pathophysiological mechanisms, highlighting the central role of cytoskeletal dynamics required for a proper achievement of cell proliferation, neuronal migration and differentiation.
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Hammock EAD, Eagleson KL, Barlow S, Earls LR, Miller DM, Levitt P. Homologs of genes expressed in Caenorhabditis elegans GABAergic neurons are also found in the developing mouse forebrain. Neural Dev 2010; 5:32. [PMID: 21122108 PMCID: PMC3006369 DOI: 10.1186/1749-8104-5-32] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2010] [Accepted: 12/01/2010] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND In an effort to identify genes that specify the mammalian forebrain, we used a comparative approach to identify mouse homologs of transcription factors expressed in developing Caenorhabditis elegans GABAergic neurons. A cell-specific microarray profiling study revealed a set of transcription factors that are highly expressed in embryonic C. elegans GABAergic neurons. RESULTS Bioinformatic analyses identified mouse protein homologs of these selected transcripts and their expression pattern was mapped in the mouse embryonic forebrain by in situ hybridization. A review of human homologs indicates several of these genes are potential candidates in neurodevelopmental disorders. CONCLUSIONS Our comparative approach has revealed several novel candidates that may serve as future targets for studies of mammalian forebrain development.
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Affiliation(s)
- Elizabeth AD Hammock
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
- Vanderbilt Kennedy Center, Vanderbilt University, Nashville, TN 37232, USA
| | - Kathie L Eagleson
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
| | - Susan Barlow
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232-8240, USA
- Siskin Hospital for Physical Rehabilitation, One Siskin Plaza, Chattanooga, TN 37403, USA
| | - Laurie R Earls
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232-8240, USA
- St Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - David M Miller
- Vanderbilt Kennedy Center, Vanderbilt University, Nashville, TN 37232, USA
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232-8240, USA
- Program in Neuroscience, Vanderbilt University, Nashville, TN 37232-8240, USA
| | - Pat Levitt
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
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Molecules and mechanisms involved in the generation and migration of cortical interneurons. ASN Neuro 2010; 2:e00031. [PMID: 20360946 PMCID: PMC2847827 DOI: 10.1042/an20090053] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Revised: 03/04/2010] [Accepted: 03/05/2010] [Indexed: 11/30/2022] Open
Abstract
The GABA (γ-aminobutyric acid)-containing interneurons of the neocortex are largely derived from the ganglionic eminences in the subpallium. Numerous studies have previously defined the migratory paths travelled by these neurons from their origins to their destinations in the cortex. We review here results of studies that have identified many of the genes expressed in the subpallium that are involved in the specification of the subtypes of cortical interneurons, and the numerous transcription factors, motogenic factors and guidance molecules that are involved in their migration.
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Key Words
- 5-HT, 5-hydroxytryptamine
- AEP, anterior entopeduncular
- BDNF, brain-derived neurotrophic factor
- CGE, caudal ganglionic eminence
- CP, cortical plate
- CR, calretinin
- CXCR, CXC chemokine receptor
- E, embryonic day
- GABA, γ-aminobutyric acid
- GABAR, GABA receptor
- HGF/SF, hepatocyte growth factor/scatter factor
- IZ, intermediate zone
- LGE, lateral ganglionic eminence
- MGE, medial ganglionic eminence
- MZ, marginal zone
- NGR, neuregulin
- NPY, neuropeptide Y
- Nrp, neuropilin
- POA, preoptic area
- PV, paravalbumin
- Robo, Roundabout
- SDF-1, stromal-derived factor 1
- SHH, sonic hedgehog
- SST, somatostatin
- SVZ, subventricular zone
- VZ, ventricular zone
- gene expression
- interneuron
- migration
- neocortex
- neuronal specification
- subpallium
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