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Edey J, Soleimani-Nouri P, Dawson-Kavanagh A, Imran Azeem MS, Episkopou V. X-linked neuronal migration disorders: Gender differences and insights for genetic screening. Int J Dev Neurosci 2023; 83:581-599. [PMID: 37574439 DOI: 10.1002/jdn.10290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Revised: 06/23/2023] [Accepted: 07/14/2023] [Indexed: 08/15/2023] Open
Abstract
Cortical development depends on neuronal migration of both excitatory and inhibitory interneurons. Neuronal migration disorders (NMDs) are conditions characterised by anatomical cortical defects leading to varying degrees of neurocognitive impairment, developmental delay and seizures. Refractory epilepsy affects 15 million people worldwide, and it is thought that cortical developmental disorders are responsible for 25% of childhood cases. However, little is known about the epidemiology of these disorders, nor are their aetiologies fully understood, though many are associated with sporadic genetic mutations. In this review, we aim to highlight X-linked NMDs including lissencephaly, periventricular nodular heterotopia and polymicrogyria because of their mostly familial inheritance pattern. We focus on the most prominent genes responsible: including DCX, ARX, FLNA, FMR1, L1CAM, SRPX2, DDX3X, NSHDL, CUL4B and OFD1, outlining what is known about their prevalence among NMDs, and the underlying pathophysiology. X-linked disorders are important to recognise clinically, as females often have milder phenotypes. Consequently, there is a greater chance they survive to reproductive age and risk passing the mutations down. Effective genetic screening is important to prevent and treat these conditions, and for this, we need to know gene mutations and have a clear understanding of the function of the genes involved. This review summarises the knowledge base and provides clear direction for future work by both scientists and clinicians alike.
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Affiliation(s)
- Juliet Edey
- Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, London, UK
| | - Payam Soleimani-Nouri
- Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, London, UK
| | | | | | - Vasso Episkopou
- Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, London, UK
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Kim SA, Ivanov AO, Halepa AA, Sysoeva AA, Gunenko GA. Surgical treatment of epilepsy in a patient with bilateral periventricular nodular heterotopia: A case report. Surg Neurol Int 2023; 14:283. [PMID: 37680926 PMCID: PMC10481799 DOI: 10.25259/sni_478_2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 07/20/2023] [Indexed: 09/09/2023] Open
Abstract
Background Periventricular nodular heterotopia (PNH) is a rare pathological condition characterized by the presence of nodules of gray matter located along the lateral ventricles of the brain. The condition typically presents with seizures and other neurological symptoms, and various methods of surgical treatment and postoperative outcomes have been described in the literature. Case Description We present a case study of a 17-year-old patient who has been experiencing seizures since the age of 13. The patient reported episodes of loss of consciousness and periodic freezing with preservation of posture. Two years later, the patient experienced his first generalized tonic-clonic seizure during nocturnal sleep and was subsequently admitted to a neurological department. A magnetic resonance imaging scan of the brain with an epilepsy protocol (3 Tesla) confirmed the presence of an extended bilateral subependymal nodular heterotopy at the level of the temporal and occipital horns of the lateral ventricles, which was larger on the left side, and a focal subcortical heterotopy of the right cerebellar hemisphere. The patient underwent a posterior quadrant disconnection surgery, which aimed to isolate the extensive epileptogenic zone in the left temporal, parietal, and occipital lobes using standard techniques. As of today, 6 months have passed since the surgery and there have been no registered epileptic seizures during this period following the surgical treatment. Conclusion Although PNHs can be extensive and located bilaterally, surgical intervention may still be an effective way to achieve seizure control in selected cases.
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Affiliation(s)
- Sergey Afanasievich Kim
- Department of Pediatric Neurosurgery, Federal Center of Neurosurgery, Novosibirsk, Russian Federation
- Research Institute of Clinical and Experimental Lymphology - Branch of the Federal State Budgetary Scientific Institution “Federal Research Center Institute of Cytology and Genetics of the Siberian Branch of the Russian Academy of Sciences”, Novosibirsk, Russia
| | - Anton Olegovich Ivanov
- Department of Pediatric Neurosurgery, Federal Center of Neurosurgery, Novosibirsk, Russian Federation
| | | | - Anna Alexeevna Sysoeva
- Department of Pediatric Neurosurgery, Federal Center of Neurosurgery, Novosibirsk, Russian Federation
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Price KM, Wigg KG, Eising E, Feng Y, Blokland K, Wilkinson M, Kerr EN, Guger SL, Fisher SE, Lovett MW, Strug LJ, Barr CL. Hypothesis-driven genome-wide association studies provide novel insights into genetics of reading disabilities. Transl Psychiatry 2022; 12:495. [PMID: 36446759 PMCID: PMC9709072 DOI: 10.1038/s41398-022-02250-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 10/24/2022] [Accepted: 11/03/2022] [Indexed: 11/30/2022] Open
Abstract
Reading Disability (RD) is often characterized by difficulties in the phonology of the language. While the molecular mechanisms underlying it are largely undetermined, loci are being revealed by genome-wide association studies (GWAS). In a previous GWAS for word reading (Price, 2020), we observed that top single-nucleotide polymorphisms (SNPs) were located near to or in genes involved in neuronal migration/axon guidance (NM/AG) or loci implicated in autism spectrum disorder (ASD). A prominent theory of RD etiology posits that it involves disturbed neuronal migration, while potential links between RD-ASD have not been extensively investigated. To improve power to identify associated loci, we up-weighted variants involved in NM/AG or ASD, separately, and performed a new Hypothesis-Driven (HD)-GWAS. The approach was applied to a Toronto RD sample and a meta-analysis of the GenLang Consortium. For the Toronto sample (n = 624), no SNPs reached significance; however, by gene-set analysis, the joint contribution of ASD-related genes passed the threshold (p~1.45 × 10-2, threshold = 2.5 × 10-2). For the GenLang Cohort (n = 26,558), SNPs in DOCK7 and CDH4 showed significant association for the NM/AG hypothesis (sFDR q = 1.02 × 10-2). To make the GenLang dataset more similar to Toronto, we repeated the analysis restricting to samples selected for reading/language deficits (n = 4152). In this GenLang selected subset, we found significant association for a locus intergenic between BTG3-C21orf91 for both hypotheses (sFDR q < 9.00 × 10-4). This study contributes candidate loci to the genetics of word reading. Data also suggest that, although different variants may be involved, alleles implicated in ASD risk may be found in the same genes as those implicated in word reading. This finding is limited to the Toronto sample suggesting that ascertainment influences genetic associations.
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Affiliation(s)
- Kaitlyn M Price
- Division of Experimental and Translational Neuroscience, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
- Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Karen G Wigg
- Division of Experimental and Translational Neuroscience, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Else Eising
- Language and Genetics Department, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands
| | - Yu Feng
- Division of Experimental and Translational Neuroscience, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Kirsten Blokland
- Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Margaret Wilkinson
- Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Elizabeth N Kerr
- Department of Psychology, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Sharon L Guger
- Department of Psychology, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Simon E Fisher
- Language and Genetics Department, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| | - Maureen W Lovett
- Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Lisa J Strug
- Genetics and Genome Biology, Hospital for Sick Children, Toronto, Ontario, Canada
- Departments of Statistical Sciences and Computer Science, Faculty of Arts and Science and Division of Biostatistics, Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
| | - Cathy L Barr
- Division of Experimental and Translational Neuroscience, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada.
- Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada.
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada.
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Curci A, Rampino A. Grey Matter Heterotopia and Criminal Responsibility in a Case of Personal Injury Defense. Front Psychiatry 2020; 11:261. [PMID: 32296357 PMCID: PMC7139628 DOI: 10.3389/fpsyt.2020.00261] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 03/17/2020] [Indexed: 11/13/2022] Open
Abstract
The abnormal allocation of nodules of grey matter in areas of the brain or spinal cord that should physiologically be occupied by white matter characterizes a neural defect called Grey Matter Heterotopia (GMH). The improvement of MRI techniques has enabled a deeper understanding of the neuropathological bases and epidemiology of such a condition. Among its major manifestations, there is the onset of epileptic seizures, mild intellectual disability, impairments in executive functioning, neurodevelopmental disorders; less frequently GMH has been found associated with depression, anxiety, and schizophrenia. Despite the clinical interest in GMH, no studies have considered the possible forensic and criminological implications of this condition. In the current study, we present a case of GMH in a young male defendant accused of having seriously injured a schoolmate as a reaction to bullying behavior. Neuropsychological and instrumental evidence converge in showing prevalence for the defendant's adoption of repressive responses to stressors, and difficulties to inhibit undesirable behavior at the long run. In the case at hand, the massive stress induced by the exposition to bullying behavior undermined inhibitory control, hence an impulsive and disproportionate reaction took place. Without appropriate therapeutic control, this reactive behavior might take place again. As a consequence, the forensic assessment recommended that the defendant was held partially liable only but that there was likelihood of recidivism. We discuss this single-case evidence for a possible role of GMH in the adoption of dyscontrolled responses to stressors, and the relevance of GMH diagnosis in forensic proceedings.
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Affiliation(s)
- Antonietta Curci
- Department of Education, Psychology, Communication, University of Bari "Aldo Moro", Bari, Italy
| | - Antonio Rampino
- Department of Basic Medical Science, Neuroscience and Sense Organs University of Bari "Aldo Moro", Bari, Italy
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Baroud E, Hourani R, Talih F. Brain Imaging in New Onset Psychiatric Presentations. INNOVATIONS IN CLINICAL NEUROSCIENCE 2019; 16:21-26. [PMID: 31037224 PMCID: PMC6450676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We report two cases of patients who presented with psychiatric symptoms and were found to have brain changes on magnetic resonance imaging. In the first case, a 19-year-old man presented with erratic behavior and odd, paranoid ideas. Imaging of the brain revealed a focus of high FLAIR signal involving the left globus pallidus. The second case was a 21-year-old woman who presented with irritability, racing thoughts, and suicidal ideation. Brain imaging revealed nodules of heterotopic grey matter in the right inferior frontal white matter and foci of subcortical heterotopia with thickening of the adjacent cortex. Both patients received psychotropic medications and showed improvement of their symptoms. Integrating neuroimaging in the evaluation of new onset or atypical psychiatric presentations might be of value in specific cases. It is important to develop clear guidelines for the use of imaging modalities in clinical psychiatric practice.
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Affiliation(s)
- Evelyne Baroud
- Drs. Baroud and Talih are with the Department of Psychiatry, American University of Beirut Medical Center in Beirut, Lebanon
- Dr. Hourani is with the Department of Diagnostic Radiology, American University of Beirut Medical Center in Beirut, Lebanon
| | - Roula Hourani
- Drs. Baroud and Talih are with the Department of Psychiatry, American University of Beirut Medical Center in Beirut, Lebanon
- Dr. Hourani is with the Department of Diagnostic Radiology, American University of Beirut Medical Center in Beirut, Lebanon
| | - Farid Talih
- Drs. Baroud and Talih are with the Department of Psychiatry, American University of Beirut Medical Center in Beirut, Lebanon
- Dr. Hourani is with the Department of Diagnostic Radiology, American University of Beirut Medical Center in Beirut, Lebanon
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Guidi LG, Velayos‐Baeza A, Martinez‐Garay I, Monaco AP, Paracchini S, Bishop DVM, Molnár Z. The neuronal migration hypothesis of dyslexia: A critical evaluation 30 years on. Eur J Neurosci 2018; 48:3212-3233. [PMID: 30218584 PMCID: PMC6282621 DOI: 10.1111/ejn.14149] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 08/06/2018] [Accepted: 08/13/2018] [Indexed: 12/29/2022]
Abstract
The capacity for language is one of the key features underlying the complexity of human cognition and its evolution. However, little is known about the neurobiological mechanisms that mediate normal or impaired linguistic ability. For developmental dyslexia, early postmortem studies conducted in the 1980s linked the disorder to subtle defects in the migration of neurons in the developing neocortex. These early studies were reinforced by human genetic analyses that identified dyslexia susceptibility genes and subsequent evidence of their involvement in neuronal migration. In this review, we examine recent experimental evidence that does not support the link between dyslexia and neuronal migration. We critically evaluate gene function studies conducted in rodent models and draw attention to the lack of robust evidence from histopathological and imaging studies in humans. Our review suggests that the neuronal migration hypothesis of dyslexia should be reconsidered, and the neurobiological basis of dyslexia should be approached with a fresh start.
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Affiliation(s)
- Luiz G. Guidi
- Department of Physiology, Anatomy, and GeneticsUniversity of OxfordOxfordUK
- Wellcome Centre for Human GeneticsUniversity of OxfordOxfordUK
| | - Antonio Velayos‐Baeza
- Department of Physiology, Anatomy, and GeneticsUniversity of OxfordOxfordUK
- Wellcome Centre for Human GeneticsUniversity of OxfordOxfordUK
| | - Isabel Martinez‐Garay
- Department of Physiology, Anatomy, and GeneticsUniversity of OxfordOxfordUK
- Division of NeuroscienceSchool of BiosciencesCardiff UniversityCardiffUK
| | | | | | | | - Zoltán Molnár
- Department of Physiology, Anatomy, and GeneticsUniversity of OxfordOxfordUK
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Lippi G. Neuropsychiatric symptoms and diagnosis of grey matter heterotopia: A case-based reflection. S Afr J Psychiatr 2017; 23:923. [PMID: 30263174 PMCID: PMC6138094 DOI: 10.4102/sajpsychiatry.v23i0.923] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 09/05/2016] [Indexed: 11/29/2022] Open
Abstract
Neuropsychiatric symptoms can be related to less common underlying neuropsychiatric conditions – in this case report, the condition discussed is that of grey matter heterotopia (GMH). The patient presented with a history of prominent aggression, impulsivity and manipulative and attention-seeking behaviour. Episodes of depression and incidents of deliberate self-harm and suicide attempts had been reported. Neuropsychiatric symptoms included anxiety, a labile mood, delusional thinking and auditory hallucinations. Testing revealed some cognitive difficulties and severe impairment of frontal lobe functions. A magnetic resonance imaging (MRI) scan of his brain revealed the presence of GMH, which had previously been misdiagnosed as tuberous sclerosis. An MRI scan of the brain is the special investigation of choice for the correct diagnosis of GMH. The pathognomonic finding is that of heterotopic grey matter abnormally located within areas of white matter. Defective foetal neuronal migration between the third and fifth month of pregnancy can lead to GMH, which can present later on in childhood or adolescence with epilepsy, intellectual impairment or reading difficulties. During the late teenage years or early adulthood, a wide variety of neuropsychiatric symptoms may be present, which can lead to diagnostic difficulties.
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Affiliation(s)
- Gian Lippi
- Department of Psychiatry, Faculty of Health Sciences, University of Pretoria, South Africa.,Forensic Unit, Weskoppies Hospital, South Africa
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Sahinoglu Z, Yapicier O, Ozcan N. Prenatal diagnosis of periventricular nodular heterotopia in borderline ventriculomegaly using sonography and magnetic resonance imaging. JOURNAL OF CLINICAL ULTRASOUND : JCU 2016; 44:510-513. [PMID: 26990213 DOI: 10.1002/jcu.22350] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 02/03/2016] [Indexed: 06/05/2023]
Abstract
Periventricular nodular heterotopia (PNH) is usually missed on prenatal sonographic examinations, even on targeted scans. Irregular ventricular walls on axial view and irregular square-shaped lateral ventricles on coronal view are suggestive of PNH in the early third trimester. To achieve an early prenatal diagnosis, it is important to keep in mind the possible coexistence of PNH with brain malformations such as ventriculomegaly, posterior fossa anomalies, or agenesis of corpus callosum. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 44:510-513, 2016.
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Affiliation(s)
- Zeki Sahinoglu
- Department of Perinatology, Clinic of Obstetrics and Gynecology, Anadolu Medical Center in affiliation with Johns Hopkins Medicine, Istanbul, Turkey.
| | - Ozlem Yapicier
- Department of Pathology, Acibadem University, Istanbul, Turkey
| | - Nahit Ozcan
- Department of Radiology, Sonomed Imaging Center, Istanbul, Turkey
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Neuronal Heterotopias Affect the Activities of Distant Brain Areas and Lead to Behavioral Deficits. J Neurosci 2015; 35:12432-45. [PMID: 26354912 DOI: 10.1523/jneurosci.3648-14.2015] [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] [Indexed: 12/21/2022] Open
Abstract
Neuronal heterotopia refers to brain malformations resulting from deficits of neuronal migration. Individuals with heterotopias show a high incidence of neurological deficits, such as epilepsy. More recently, it has come to be recognized that focal heterotopias may also show a range of psychiatric problems, including cognitive and behavioral impairments. However, because focal heterotopias are not always located in the brain areas responsible for the symptoms, the causal relationship between the symptoms and heterotopias remains elusive. In this study, we showed that mice with focal heterotopias in the somatosensory cortex generated by in utero electroporation exhibited spatial working memory deficit and low competitive dominance behavior, which have been shown to be closely associated with the activity of the medial prefrontal cortex (mPFC) in rodents. Analysis of the mPFC activity revealed that the immediate-early gene expression was decreased and the local field potentials of the mPFC were altered in the mice with heterotopias compared with the control mice. Moreover, activation of these ectopic and overlying sister neurons using the DREADD (designer receptor exclusively activated by designer drug) system improved the working memory deficits. These findings suggest that cortical regions containing focal heterotopias can affect distant brain regions and give rise to behavioral abnormalities. Significance statement: Recent studies reported that patients with heterotopias have a variety of clinical symptoms, such as cognitive disturbance, psychiatric symptoms, and autistic behavior. However, the causal relationship between the symptoms and heterotopias remains elusive. Here we showed that mice with focal heterotopias in the somatosensory cortex generated by in utero electroporation exhibited behavioral deficits that have been shown to be associated with the mPFC activity in rodents. The existence of heterotopias indeed altered the neural activities of the mPFC, and direct manipulation of the neural activity of the ectopic neurons and their sister neurons in the overlying cortex improved the behavioral deficit. Thus, our results indicate that focal heterotopias could affect the activities of distant brain areas and cause behavioral abnormalities.
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Lenck-Santini PP, Scott RC. Mechanisms Responsible for Cognitive Impairment in Epilepsy. Cold Spring Harb Perspect Med 2015; 5:cshperspect.a022772. [PMID: 26337111 DOI: 10.1101/cshperspect.a022772] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Epilepsy is often associated with cognitive and behavioral impairments that can have profound impact on the quality of life of patients. Although the mechanisms of cognitive impairment are not completely understood, we make an attempt to describe, from a systems perspective, how information processing is affected in epilepsy disorders. The aim of this review is to (1) define the nature of cognitive deficits associated with epilepsy, (2) review fundamental systems-level mechanisms underlying information processing, and (3) describe how information processing is dysfunctional in epilepsy and investigate the relative contributions of etiology, seizures, and interictal discharges (IDs). We conclude that these mechanisms are likely to be important and deserve more detailed scrutiny in the future.
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Affiliation(s)
| | - Rodney C Scott
- Institute of Child Health, University College of London, London WC1N 3JH, United Kingdom
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Kasper BS, Kurzbuch K, Chang BS, Pauli E, Hamer HM, Winkler J, Hehr U. Paternal inheritance of classic X-linked bilateral periventricular nodular heterotopia. Am J Med Genet A 2013; 161A:1323-8. [DOI: 10.1002/ajmg.a.35917] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Accepted: 02/04/2013] [Indexed: 11/09/2022]
Affiliation(s)
- Burkhard S. Kasper
- Department of Neurology; Epilepsy Center, Erlangen University; Erlangen; Germany
| | - Katrin Kurzbuch
- Department of Neurology; Epilepsy Center, Erlangen University; Erlangen; Germany
| | - Bernard S. Chang
- Department of Neurology; Comprehensive Epilepsy Center, Beth Israel Deaconess Medical Center and Harvard Medical School; Boston, Massachusetts
| | - Elisabeth Pauli
- Department of Neurology; Epilepsy Center, Erlangen University; Erlangen; Germany
| | - Hajo M. Hamer
- Department of Neurology; Epilepsy Center, Erlangen University; Erlangen; Germany
| | - Jürgen Winkler
- Department of Neurology; Molecular Neurology, Erlangen University; Erlangen; Germany
| | - Ute Hehr
- Department of Human Genetics; Center for Human Genetics, University of Regensburg; Regensburg; Germany
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Sheen VL. Periventricular Heterotopia: Shuttling of Proteins through Vesicles and Actin in Cortical Development and Disease. SCIENTIFICA 2012; 2012:480129. [PMID: 24278701 PMCID: PMC3820590 DOI: 10.6064/2012/480129] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2012] [Accepted: 10/14/2012] [Indexed: 06/02/2023]
Abstract
During cortical development, proliferating neural progenitors exhibit polarized apical and basolateral membranes that are maintained by tightly controlled and membrane-specific vesicular trafficking pathways. Disruption of polarity through impaired delivery of proteins can alter cell fate decisions and consequent expansion of the progenitor pool, as well as impact the integrity of the neuroependymal lining. Loss of neuroependymal integrity disrupts radial glial scaffolding and alters initial neuronal migration from the ventricular zone. Vesicle trafficking is also required for maintenance of lipid and protein cycling within the leading and trailing edge of migratory neurons, as well as dendrites and synapses of mature neurons. Defects in this transport machinery disrupt neuronal identity, migration, and connectivity and give rise to a malformation of cortical development termed as periventricular heterotopia (PH). PH is characterized by a reduction in brain size, ectopic clusters of neurons localized along the lateral ventricle, and epilepsy and dyslexia. These anatomical anomalies correlate with developmental impairments in neural progenitor proliferation and specification, migration from loss of neuroependymal integrity and neuronal motility, and aberrant neuronal process extension. Genes causal for PH regulate vesicle-mediated endocytosis along an actin cytoskeletal network. This paper explores the role of these dynamic processes in cortical development and disease.
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Affiliation(s)
- Volney L. Sheen
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02115, USA
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