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Sepulveda W, Sepulveda F, Schonstedt V, Stern J, Diaz-Serani R. Neuroimaging Findings in Fetal Hemimegalencephaly: Case Study and Review. Fetal Diagn Ther 2023; 51:133-144. [PMID: 38008087 DOI: 10.1159/000535406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 11/17/2023] [Indexed: 11/28/2023]
Abstract
BACKGROUND Limited information exists in the prenatal literature regarding the neuroimaging features of fetal hemimegalencephaly. SUMMARY This report describes ultrasound and magnetic resonance imaging (MRI) findings in a second-trimester fetus with an isolated, severe form of hemimegalencephaly. The most prominent imaging findings included unilateral enlarged cerebral hemisphere and ipsilateral ventriculomegaly causing cerebral asymmetry, midline shift, and macrocephaly. Abnormal cortical development imaging signs were also evident. A literature review encompassing 23 reports describing 36 cases, including ours, is presented. KEY MESSAGES Characteristic ultrasound findings for the diagnosis of hemimegalencephaly are not always apparent prenatally. Asymmetric ventriculomegaly emerges as the most common but nonspecific presenting feature during routine second- or third-trimester ultrasound scans. Subsequent high-resolution prenatal neurosonography and fetal MRI facilitate definitive prenatal diagnosis, showcasting associated features primarily related to cortical migration, differentiation, and maturation. Postnatally, the prognosis is poor due to intractable seizures, hemiplegia, and progressive neurodevelopmental delay.
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Affiliation(s)
- Waldo Sepulveda
- FETALMED-Maternal-Fetal Diagnostic Center, Fetal Imaging Unit, Santiago, Chile
| | - Francisco Sepulveda
- FETALMED-Maternal-Fetal Diagnostic Center, Fetal Imaging Unit, Santiago, Chile
- Department of Radiology, Clinica Alemana, Santiago, Chile
- Department of Neuroradiology, Institute of Neurosurgery "Dr. Alfonso Asenjo", National Health Service, Santiago, Chile
| | | | - Jocelyn Stern
- FETALMED-Maternal-Fetal Diagnostic Center, Fetal Imaging Unit, Santiago, Chile
| | - Ricardo Diaz-Serani
- Maternal-Fetal Medicine Unit, Department of Obstetrics and Gynecology, Clinica BUPA, Santiago, Chile
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Baldassari S, Ribierre T, Marsan E, Adle-Biassette H, Ferrand-Sorbets S, Bulteau C, Dorison N, Fohlen M, Polivka M, Weckhuysen S, Dorfmüller G, Chipaux M, Baulac S. Dissecting the genetic basis of focal cortical dysplasia: a large cohort study. Acta Neuropathol 2019; 138:885-900. [PMID: 31444548 PMCID: PMC6851393 DOI: 10.1007/s00401-019-02061-5] [Citation(s) in RCA: 168] [Impact Index Per Article: 33.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 07/05/2019] [Accepted: 08/11/2019] [Indexed: 12/24/2022]
Abstract
Genetic malformations of cortical development (MCDs), such as mild MCDs (mMCD), focal cortical dysplasia (FCD), and hemimegalencephaly (HME), are major causes of severe pediatric refractory epilepsies subjected to neurosurgery. FCD2 are characterized by neuropathological hallmarks that include enlarged dysmorphic neurons (DNs) and balloon cells (BCs). Here, we provide a comprehensive assessment of the contribution of germline and somatic variants in a large cohort of surgical MCD cases. We enrolled in a monocentric study 80 children with drug-resistant epilepsy and a postsurgical neuropathological diagnosis of mMCD, FCD1, FCD2, or HME. We performed targeted gene sequencing ( ≥ 2000X read depth) on matched blood-brain samples to search for low-allele frequency variants in mTOR pathway and FCD genes. We were able to elucidate 29% of mMCD/FCD1 patients and 63% of FCD2/HME patients. Somatic loss-of-function variants in the N-glycosylation pathway-associated SLC35A2 gene were found in mMCD/FCD1 cases. Somatic gain-of-function variants in MTOR and its activators (AKT3, PIK3CA, RHEB), as well as germline, somatic and two-hit loss-of-function variants in its repressors (DEPDC5, TSC1, TSC2) were found exclusively in FCD2/HME cases. We show that panel-negative FCD2 cases display strong pS6-immunostaining, stressing that all FCD2 are mTORopathies. Analysis of microdissected cells demonstrated that DNs and BCs carry the pathogenic variants. We further observed a correlation between the density of pathological cells and the variant-detection likelihood. Single-cell microdissection followed by sequencing of enriched pools of DNs unveiled a somatic second-hit loss-of-heterozygosity in a DEPDC5 germline case. In conclusion, this study indicates that mMCD/FCD1 and FCD2/HME are two distinct genetic entities: while all FCD2/HME are mosaic mTORopathies, mMCD/FCD1 are not caused by mTOR-pathway-hyperactivating variants, and ~ 30% of the cases are related to glycosylation defects. We provide a framework for efficient genetic testing in FCD/HME, linking neuropathology to genetic findings and emphasizing the usefulness of molecular evaluation in the pediatric epileptic neurosurgical population.
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Affiliation(s)
- Sara Baldassari
- Sorbonne Université, UPMC Univ Paris 06, UMR S 1127, Paris, France
- INSERM, U1127, Paris, France
- CNRS, UMR 7225, Paris, France
- Institut du Cerveau et de la Moelle épinière (ICM), Hôpital Pitié-Salpêtrière-47, bd de l'hôpital, 75013, Paris, France
| | - Théo Ribierre
- Sorbonne Université, UPMC Univ Paris 06, UMR S 1127, Paris, France
- INSERM, U1127, Paris, France
- CNRS, UMR 7225, Paris, France
- Institut du Cerveau et de la Moelle épinière (ICM), Hôpital Pitié-Salpêtrière-47, bd de l'hôpital, 75013, Paris, France
| | - Elise Marsan
- Sorbonne Université, UPMC Univ Paris 06, UMR S 1127, Paris, France
- INSERM, U1127, Paris, France
- CNRS, UMR 7225, Paris, France
- Institut du Cerveau et de la Moelle épinière (ICM), Hôpital Pitié-Salpêtrière-47, bd de l'hôpital, 75013, Paris, France
| | - Homa Adle-Biassette
- INSERM UMR 1141, Hôpital Robert-Debré, 75019, Paris, France
- Faculté de Médecine Denis Diderot, Université Paris 7, Paris, France
- Service d'Anatomie et de Cytologie Pathologiques, Hôpital Lariboisière, APHP, 75010, Paris, France
| | - Sarah Ferrand-Sorbets
- Department of Pediatric Neurosurgery, Rothschild Foundation Hospital, 75019, Paris, France
| | - Christine Bulteau
- Department of Pediatric Neurosurgery, Rothschild Foundation Hospital, 75019, Paris, France
| | - Nathalie Dorison
- Department of Pediatric Neurosurgery, Rothschild Foundation Hospital, 75019, Paris, France
| | - Martine Fohlen
- Department of Pediatric Neurosurgery, Rothschild Foundation Hospital, 75019, Paris, France
| | - Marc Polivka
- Service d'Anatomie et de Cytologie Pathologiques, Hôpital Lariboisière, APHP, 75010, Paris, France
| | - Sarah Weckhuysen
- Sorbonne Université, UPMC Univ Paris 06, UMR S 1127, Paris, France
- INSERM, U1127, Paris, France
- CNRS, UMR 7225, Paris, France
- Institut du Cerveau et de la Moelle épinière (ICM), Hôpital Pitié-Salpêtrière-47, bd de l'hôpital, 75013, Paris, France
- Department of Neurology, University Hospital Antwerp, Antwerp, Belgium
| | - Georg Dorfmüller
- Department of Pediatric Neurosurgery, Rothschild Foundation Hospital, 75019, Paris, France
| | - Mathilde Chipaux
- Department of Pediatric Neurosurgery, Rothschild Foundation Hospital, 75019, Paris, France
| | - Stéphanie Baulac
- Sorbonne Université, UPMC Univ Paris 06, UMR S 1127, Paris, France.
- INSERM, U1127, Paris, France.
- CNRS, UMR 7225, Paris, France.
- Institut du Cerveau et de la Moelle épinière (ICM), Hôpital Pitié-Salpêtrière-47, bd de l'hôpital, 75013, Paris, France.
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Park SM, Lim JS, Ramakrishina S, Kim SH, Kim WK, Lee J, Kang HC, Reiter JF, Kim DS, Kim HH, Lee JH. Brain Somatic Mutations in MTOR Disrupt Neuronal Ciliogenesis, Leading to Focal Cortical Dyslamination. Neuron 2018; 99:83-97.e7. [PMID: 29937275 DOI: 10.1016/j.neuron.2018.05.039] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 04/06/2018] [Accepted: 05/25/2018] [Indexed: 12/21/2022]
Abstract
Focal malformations of cortical development (FMCDs), including focal cortical dysplasia (FCD) and hemimegalencephaly (HME), are major etiologies of pediatric intractable epilepsies exhibiting cortical dyslamination. Brain somatic mutations in MTOR have recently been identified as a major genetic cause of FMCDs. However, the molecular mechanism by which these mutations lead to cortical dyslamination remains poorly understood. Here, using patient tissue, genome-edited cells, and mouse models with brain somatic mutations in MTOR, we discovered that disruption of neuronal ciliogenesis by the mutations underlies cortical dyslamination in FMCDs. We found that abnormal accumulation of OFD1 at centriolar satellites due to perturbed autophagy was responsible for the defective neuronal ciliogenesis. Additionally, we found that disrupted neuronal ciliogenesis accounted for cortical dyslamination in FMCDs by compromising Wnt signals essential for neuronal polarization. Altogether, this study describes a molecular mechanism by which brain somatic mutations in MTOR contribute to the pathogenesis of cortical dyslamination in FMCDs.
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Affiliation(s)
- Sang Min Park
- Biomedical Science and Engineering Interdisciplinary Program, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Jae Seok Lim
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Suresh Ramakrishina
- Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul 04763, Republic of Korea
| | - Se Hoon Kim
- Department of Pathology, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
| | - Woo Kyeong Kim
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Junehawk Lee
- Biomedical HPC Technology Research Center, KISTI, Daejeon 34141, Republic of Korea
| | - Hoon-Chul Kang
- Division of Pediatric Neurology, Department of Pediatrics, Pediatric Epilepsy Clinics, Severance Children's Hospital, Epilepsy Research Institute, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
| | - Jeremy F Reiter
- Department of Biochemistry and Biophysics, Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Dong Seok Kim
- Pediatric Neurosurgery, Severance Children's Hospital, Department of Neurosurgery, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
| | - Hyongbum Henry Kim
- Department of Pharmacology, Brain Korea 21 Plus Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
| | - Jeong Ho Lee
- Biomedical Science and Engineering Interdisciplinary Program, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea; Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea; Center for Synaptic Brain Dysfunctions, Institute for Basic Science, Daejeon 34141, Republic of Korea.
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4
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D'Gama AM, Woodworth MB, Hossain AA, Bizzotto S, Hatem NE, LaCoursiere CM, Najm I, Ying Z, Yang E, Barkovich AJ, Kwiatkowski DJ, Vinters HV, Madsen JR, Mathern GW, Blümcke I, Poduri A, Walsh CA. Somatic Mutations Activating the mTOR Pathway in Dorsal Telencephalic Progenitors Cause a Continuum of Cortical Dysplasias. Cell Rep 2017; 21:3754-3766. [PMID: 29281825 PMCID: PMC5752134 DOI: 10.1016/j.celrep.2017.11.106] [Citation(s) in RCA: 199] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2017] [Revised: 10/02/2017] [Accepted: 11/29/2017] [Indexed: 01/16/2023] Open
Abstract
Focal cortical dysplasia (FCD) and hemimegalencephaly (HME) are epileptogenic neurodevelopmental malformations caused by mutations in mTOR pathway genes. Deep sequencing of these genes in FCD/HME brain tissue identified an etiology in 27 of 66 cases (41%). Radiographically indistinguishable lesions are caused by somatic activating mutations in AKT3, MTOR, and PIK3CA and germline loss-of-function mutations in DEPDC5, NPRL2, and TSC1/2, including TSC2 mutations in isolated HME demonstrating a "two-hit" model. Mutations in the same gene cause a disease continuum from FCD to HME to bilateral brain overgrowth, reflecting the progenitor cell and developmental time when the mutation occurred. Single-cell sequencing demonstrated mTOR activation in neurons in all lesions. Conditional Pik3ca activation in the mouse cortex showed that mTOR activation in excitatory neurons and glia, but not interneurons, is sufficient for abnormal cortical overgrowth. These data suggest that mTOR activation in dorsal telencephalic progenitors, in some cases specifically the excitatory neuron lineage, causes cortical dysplasia.
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Affiliation(s)
- Alissa M D'Gama
- Division of Genetics and Genomics, Manton Center for Orphan Disease, and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115, USA; Departments of Pediatrics and Neurology, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
| | - Mollie B Woodworth
- Division of Genetics and Genomics, Manton Center for Orphan Disease, and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115, USA; Departments of Pediatrics and Neurology, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
| | - Amer A Hossain
- Division of Genetics and Genomics, Manton Center for Orphan Disease, and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115, USA; Departments of Pediatrics and Neurology, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
| | - Sara Bizzotto
- Division of Genetics and Genomics, Manton Center for Orphan Disease, and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115, USA; Departments of Pediatrics and Neurology, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
| | - Nicole E Hatem
- Division of Genetics and Genomics, Manton Center for Orphan Disease, and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115, USA; Departments of Pediatrics and Neurology, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
| | | | - Imad Najm
- Epilepsy Center, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Zhong Ying
- Epilepsy Center, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Edward Yang
- Department of Radiology, Boston Children's Hospital, Boston, MA 02115, USA; Department of Radiology, Harvard Medical School, Boston, MA 02115, USA
| | - A James Barkovich
- Departments of Radiology and Diagnostic Imaging, Neurology, Pediatrics, and Neurosurgery, University of California, San Francisco, San Francisco, CA 94143, USA
| | | | - Harry V Vinters
- Departments of Pathology and Laboratory Medicine (Neuropathology) and Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Joseph R Madsen
- Department of Neurosurgery, Boston Children's Hospital, Boston, MA, USA
| | - Gary W Mathern
- Departments of Neurosurgery and Psychiatry and Biobehavioral Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Ingmar Blümcke
- Epilepsy Center, Cleveland Clinic, Cleveland, OH 44195, USA; Department of Neuropathology, University Hospital Erlangen, Schwabachanlage 6, 91054 Erlangen, Germany
| | - Annapurna Poduri
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA; Epilepsy Genetics Program, Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Boston, MA 02115, USA
| | - Christopher A Walsh
- Division of Genetics and Genomics, Manton Center for Orphan Disease, and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115, USA; Departments of Pediatrics and Neurology, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA.
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