51
|
Lee S, Lee JH. Brain somatic mutations as RNA therapeutic targets in neurological disorders. Ann N Y Acad Sci 2022; 1514:11-20. [PMID: 35527236 DOI: 10.1111/nyas.14786] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Research into the genetic etiology of a neurological disorder can provide directions for genetic diagnosis and targeted therapy. In the past, germline mutations, which are transmitted from parents or newly arise from parental germ cells, were considered as major genetic causes of neurological disorders. However, recent evidence has shown that somatic mutations in the brain, which can arise from neural stem cells during development or over aging, account for a significant number of brain disorders, ranging from neurodevelopmental, neurodegenerative, and neuropsychiatric to neoplastic disease. Moreover, the identification of disease-causing somatic mutations or mutated genes has provided new insights into molecular pathogenesis and unveiled potential therapeutic targets for treating neurological disorders that have few, or no, therapeutic options. RNA therapeutics, including antisense oligonucleotide (ASO) and small interfering RNA (siRNA), are emerging as promising therapeutic tools for treating genetic neurological disorders. As the number of approved and investigational ASO and siRNA drugs for neurological disorders associated with germline mutations increases, they may also prove to be attractive modalities for treating neurologic disorders resulting from somatic mutations. In this perspective, we highlight several neurological diseases caused by brain somatic mutations and discuss the potential role of RNA therapeutics in these conditions.
Collapse
Affiliation(s)
- Sungyul Lee
- SoVarGen Co., Ltd., Daejeon, Republic of Korea
| | - Jeong Ho Lee
- SoVarGen Co., Ltd., Daejeon, Republic of Korea.,Graduate School of Medical Science and Engineering, Korea Advanced Institute Science and Technology (KAIST), KAIST BioMedical Research Center, Daejeon, Republic of Korea
| |
Collapse
|
52
|
Samanta D. DEPDC5-related epilepsy: A comprehensive review. Epilepsy Behav 2022; 130:108678. [PMID: 35429726 DOI: 10.1016/j.yebeh.2022.108678] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 03/07/2022] [Accepted: 03/21/2022] [Indexed: 11/03/2022]
Abstract
DEPDC5-related epilepsy, caused by pathogenic germline variants(with or without additional somatic variants in the brain) of DEPDC5 (Dishevelled, Egl-10 and Pleckstrin domain-containing protein 5) gene, is a newly discovered predominantly focal epilepsy linked to enhanced mTORC1 pathway. DEPDC5-related epilepsy includes several familial epilepsy syndromes, including familial focal epilepsy with variable foci (FFEVF) and rare sporadic nonlesional focal epilepsy. DEPDC5 has been identified as one of the more common epilepsy genes linked to infantile spasms and sudden unexpected death (SUDEP). Although intelligence usually is unaffected in DEPDC5-related epilepsy, some people have been diagnosed with intellectual disabilities, autism spectrum disorder, and other psychiatric problems. DEPDC5 variants have also been found in 20% of individuals with various brain abnormalities, challenging the traditional distinction between lesional and nonlesional epilepsies. The most exciting development of DEPDC5 variants is the possibility of precision therapeutics using mTOR inhibitors, as evidenced with phenotypic rescue in many animal models. However, more research is needed to better understand the functional impact of diverse (particularly missense or splice-region) variants, the specific involvement of DEPDC5 in epileptogenesis, and the creation and utilization of precision therapies in humans. Precision treatments for DEPDC5-related epilepsy will benefit not only a small number of people with the condition, but they will also pave the way for new therapeutic approaches in epilepsy (including acquired epilepsies in which mTORC1 activation occurs, for example, post-traumatic epilepsy) and other neurological disorders involving a dysfunctional mTOR pathway.
Collapse
Affiliation(s)
- Debopam Samanta
- Child Neurology Section, Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR, United States.
| |
Collapse
|
53
|
Moloney PB, Dugan P, Widdess-Walsh P, Devinsky O, Delanty N. Genomics in the Presurgical Epilepsy Evaluation. Epilepsy Res 2022; 184:106951. [DOI: 10.1016/j.eplepsyres.2022.106951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 04/23/2022] [Accepted: 05/25/2022] [Indexed: 11/03/2022]
|
54
|
Pirozzi F, Berkseth M, Shear R, Gonzalez L, Timms AE, Sulc J, Pao E, Oyama N, Forzano F, Conti V, Guerrini R, Doherty ES, Saitta SC, Lockwood CM, Pritchard CC, Dobyns WB, Novotny E, Wright JNN, Saneto RP, Friedman S, Hauptman J, Ojemann J, Kapur RP, Mirzaa GM. Profiling PI3K-AKT-MTOR variants in focal brain malformations reveals new insights for diagnostic care. Brain 2022; 145:925-938. [PMID: 35355055 PMCID: PMC9630661 DOI: 10.1093/brain/awab376] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 09/04/2021] [Accepted: 09/09/2021] [Indexed: 12/28/2022] Open
Abstract
Focal malformations of cortical development including focal cortical dysplasia, hemimegalencephaly and megalencephaly, are a spectrum of neurodevelopmental disorders associated with brain overgrowth, cellular and architectural dysplasia, intractable epilepsy, autism and intellectual disability. Importantly, focal cortical dysplasia is the most common cause of focal intractable paediatric epilepsy. Gain and loss of function variants in the PI3K-AKT-MTOR pathway have been identified in this spectrum, with variable levels of mosaicism and tissue distribution. In this study, we performed deep molecular profiling of common PI3K-AKT-MTOR pathway variants in surgically resected tissues using droplet digital polymerase chain reaction (ddPCR), combined with analysis of key phenotype data. A total of 159 samples, including 124 brain tissue samples, were collected from 58 children with focal malformations of cortical development. We designed an ultra-sensitive and highly targeted molecular diagnostic panel using ddPCR for six mutational hotspots in three PI3K-AKT-MTOR pathway genes, namely PIK3CA (p.E542K, p.E545K, p.H1047R), AKT3 (p.E17K) and MTOR (p.S2215F, p.S2215Y). We quantified the level of mosaicism across all samples and correlated genotypes with key clinical, neuroimaging and histopathological data. Pathogenic variants were identified in 17 individuals, with an overall molecular solve rate of 29.31%. Variant allele fractions ranged from 0.14 to 22.67% across all mutation-positive samples. Our data show that pathogenic MTOR variants are mostly associated with focal cortical dysplasia, whereas pathogenic PIK3CA variants are more frequent in hemimegalencephaly. Further, the presence of one of these hotspot mutations correlated with earlier onset of epilepsy. However, levels of mosaicism did not correlate with the severity of the cortical malformation by neuroimaging or histopathology. Importantly, we could not identify these mutational hotspots in other types of surgically resected epileptic lesions (e.g. polymicrogyria or mesial temporal sclerosis) suggesting that PI3K-AKT-MTOR mutations are specifically causal in the focal cortical dysplasia-hemimegalencephaly spectrum. Finally, our data suggest that ultra-sensitive molecular profiling of the most common PI3K-AKT-MTOR mutations by targeted sequencing droplet digital polymerase chain reaction is an effective molecular approach for these disorders with a good diagnostic yield when paired with neuroimaging and histopathology.
Collapse
Affiliation(s)
- Filomena Pirozzi
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Matthew Berkseth
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Rylee Shear
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA
| | | | - Andrew E Timms
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Josef Sulc
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Emily Pao
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Nora Oyama
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Francesca Forzano
- Department of Clinical Genetics, Guy's and St Thomas NHS Foundation Trust and King's College London, London, UK
| | - Valerio Conti
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Children's Hospital A. Meyer-University of Florence, Italy
| | - Renzo Guerrini
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Children's Hospital A. Meyer-University of Florence, Italy
| | - Emily S Doherty
- Section of Clinical Genetics, Carilion Clinic Children's Hospital, Roanoke, VA, USA
| | - Sulagna C Saitta
- Division of Medical Genetics, Department of Obstetrics and Gynecology, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA, USA
| | - Christina M Lockwood
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, USA.,Brotman-Baty Institute for Precision Medicine, University of Minnesota, Seattle, WA, USA
| | - Colin C Pritchard
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, USA.,Brotman-Baty Institute for Precision Medicine, University of Minnesota, Seattle, WA, USA
| | - William B Dobyns
- Division of Genetics and Metabolism, Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA
| | - Edward Novotny
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA.,Division of Pediatric Neurology, Department of Neurology, Seattle Children's Hospital, Seattle, WA, USA.,Department of Neurology, University of Washington, Seattle, WA, USA
| | - Jason N N Wright
- Department of Radiology, Seattle Children's Hospital, Seattle, WA, USA
| | - Russell P Saneto
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA.,Division of Pediatric Neurology, Department of Neurology, Seattle Children's Hospital, Seattle, WA, USA
| | - Seth Friedman
- Center for Clinical and Translational Research, Seattle Children's Hospital, Seattle, WA, USA
| | - Jason Hauptman
- Department of Neurological Surgery, University of Washington, Seattle, WA, USA
| | - Jeffrey Ojemann
- Department of Neurological Surgery, University of Washington, Seattle, WA, USA
| | - Raj P Kapur
- Department of Laboratories, Seattle Children's Hospital, Seattle, WA, USA
| | - Ghayda M Mirzaa
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA.,Brotman-Baty Institute for Precision Medicine, University of Minnesota, Seattle, WA, USA.,Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, WA, USA.,Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA
| |
Collapse
|
55
|
Genetic mosaicism in the human brain: from lineage tracing to neuropsychiatric disorders. Nat Rev Neurosci 2022; 23:275-286. [PMID: 35322263 DOI: 10.1038/s41583-022-00572-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/11/2022] [Indexed: 12/18/2022]
Abstract
Genetic mosaicism is the result of the accumulation of somatic mutations in the human genome starting from the first postzygotic cell generation and continuing throughout the whole life of an individual. The rapid development of next-generation and single-cell sequencing technologies is now allowing the study of genetic mosaicism in normal tissues, revealing unprecedented insights into their clonal architecture and physiology. The somatic variant repertoire of an adult human neuron is the result of somatic mutations that accumulate in the brain by different mechanisms and at different rates during development and ageing. Non-pathogenic developmental mutations function as natural barcodes that once identified in deep bulk or single-cell sequencing can be used to retrospectively reconstruct human lineages. This approach has revealed novel insights into the clonal structure of the human brain, which is a mosaic of clones traceable to the early embryo that contribute differentially to the brain and distinct areas of the cortex. Some of the mutations happening during development, however, have a pathogenic effect and can contribute to some epileptic malformations of cortical development and autism spectrum disorder. In this Review, we discuss recent findings in the context of genetic mosaicism and their implications for brain development and disease.
Collapse
|
56
|
NPRL2 Inhibition of mTORC1 Controls Sodium Channel Expression and Brain Amino Acid Homeostasis. eNeuro 2022; 9:ENEURO.0317-21.2022. [PMID: 35165201 PMCID: PMC8896560 DOI: 10.1523/eneuro.0317-21.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 02/07/2022] [Accepted: 02/08/2022] [Indexed: 12/19/2022] Open
Abstract
Genetic mutations in nitrogen permease regulator-like 2 (NPRL2) are associated with a wide spectrum of familial focal epilepsies, autism, and sudden unexpected death of epileptics (SUDEP), but the mechanisms by which NPRL2 contributes to these effects are not well known. NPRL2 is a requisite subunit of the GAP activity toward Rags 1 (GATOR1) complex, which functions as a negative regulator of mammalian target of rapamycin complex 1 (mTORC1) kinase when intracellular amino acids are low. Here, we show that loss of NPRL2 expression in mouse excitatory glutamatergic neurons causes seizures before death, consistent with SUDEP in humans with epilepsy. Additionally, the absence of NPRL2 expression increases mTORC1-dependent signal transduction and significantly alters amino acid homeostasis in the brain. Loss of NPRL2 reduces dendritic branching and increases the strength of electrically stimulated action potentials (APs) in neurons. The increased AP strength is consistent with elevated expression of epilepsy-linked, voltage-gated sodium channels in the NPRL2-deficient brain. Targeted deletion of NPRL2 in primary neurons increases the expression of sodium channel Scn1A, whereas treatment with the pharmacological mTORC1 inhibitor called rapamycin prevents Scn1A upregulation. These studies demonstrate a novel role of NPRL2 and mTORC1 signaling in the regulation of sodium channels, which can contribute to seizures and early lethality.
Collapse
|
57
|
Scheffer IE. Lightning progress in child neurology in the past 20 years. Lancet Neurol 2022; 21:111-113. [DOI: 10.1016/s1474-4422(22)00002-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 12/21/2021] [Indexed: 11/29/2022]
|
58
|
Bennett MF, Hildebrand MS, Kayumi S, Corbett MA, Gupta S, Ye Z, Krivanek M, Burgess R, Henry OJ, Damiano JA, Boys A, Gécz J, Bahlo M, Scheffer IE, Berkovic SF. Evidence for a Dual-Pathway, 2-Hit Genetic Model for Focal Cortical Dysplasia and Epilepsy. NEUROLOGY GENETICS 2022; 8:e652. [PMID: 35097204 PMCID: PMC8789218 DOI: 10.1212/nxg.0000000000000652] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 12/03/2021] [Indexed: 12/31/2022]
Abstract
Background and Objectives The 2-hit model of genetic disease is well established in cancer, yet has
only recently been reported to cause brain malformations associated with
epilepsy. Pathogenic germline and somatic variants in genes in the
mechanistic target of rapamycin (mTOR) pathway have been implicated in
several malformations of cortical development. We investigated the 2-hit
model by performing genetic analysis and searching for germline and somatic
variants in genes in the mTOR and related pathways. Methods We searched for germline and somatic pathogenic variants in 2 brothers with
drug-resistant focal epilepsy and surgically resected focal cortical
dysplasia (FCD) type IIA. Exome sequencing was performed on blood- and
brain-derived DNA to identify pathogenic variants, which were validated by
droplet digital PCR. In vitro functional assays of a somatic variant were
performed. Results Exome analysis revealed a novel, maternally inherited, germline pathogenic
truncation variant (c.48delG; p.Ser17Alafs*70) in
NPRL3 in both brothers. NPRL3 is a
known FCD gene that encodes a negative regulator of the mTOR pathway.
Somatic variant calling in brain-derived DNA from both brothers revealed a
low allele fraction somatic variant (c.338C>T; p.Ala113Val) in the
WNT2 gene in 1 brother, confirmed by droplet digital
PCR. In vitro functional studies suggested a loss of WNT2 function as a
consequence of this variant. A second somatic variant has not yet been found
in the other brother. Discussion We identify a pathogenic germline mTOR pathway variant
(NPRL3) and a somatic variant (WNT2)
in the intersecting WNT signaling pathway, potentially implicating the
WNT2 gene in FCD and supporting a dual-pathway 2-hit
model. If confirmed in other cases, this would extend the 2-hit model to
pathogenic variants in different genes in critical, intersecting pathways in
a malformation of cortical development. Detection of low allele fraction
somatic second hits is challenging but promises to unravel the molecular
architecture of FCDs.
Collapse
|
59
|
Cortical Dysplasia and the mTOR Pathway: How the Study of Human Brain Tissue Has Led to Insights into Epileptogenesis. Int J Mol Sci 2022; 23:ijms23031344. [PMID: 35163267 PMCID: PMC8835853 DOI: 10.3390/ijms23031344] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 01/14/2022] [Accepted: 01/16/2022] [Indexed: 02/01/2023] Open
Abstract
Type II focal cortical dysplasia (FCD) is a neuropathological entity characterised by cortical dyslamination with the presence of dysmorphic neurons only (FCDIIA) or the presence of both dysmorphic neurons and balloon cells (FCDIIB). The year 2021 marks the 50th anniversary of the recognition of FCD as a cause of drug resistant epilepsy, and it is now the most common reason for epilepsy surgery. The causes of FCD remained unknown until relatively recently. The study of resected human FCD tissue using novel genomic technologies has led to remarkable advances in understanding the genetic basis of FCD. Mechanistic parallels have emerged between these non-neoplastic lesions and neoplastic disorders of cell growth and differentiation, especially through perturbations of the mammalian target of rapamycin (mTOR) signalling pathway. This narrative review presents the advances through which the aetiology of FCDII has been elucidated in chronological order, from recognition of an association between FCD and the mTOR pathway to the identification of somatic mosaicism within FCD tissue. We discuss the role of a two-hit mechanism, highlight current challenges and future directions in detecting somatic mosaicism in brain and discuss how knowledge of FCD may inform novel precision treatments of these focal epileptogenic malformations of human cortical development.
Collapse
|
60
|
Deb BK, Bateup HS. Modeling Somatic Mutations Associated With Neurodevelopmental Disorders in Human Brain Organoids. Front Mol Neurosci 2022; 14:787243. [PMID: 35058746 PMCID: PMC8764387 DOI: 10.3389/fnmol.2021.787243] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 11/30/2021] [Indexed: 11/13/2022] Open
Abstract
Neurodevelopmental disorders (NDDs) are a collection of diseases with early life onset that often present with developmental delay, cognitive deficits, and behavioral conditions. In some cases, severe outcomes such as brain malformations and intractable epilepsy can occur. The mutations underlying NDDs may be inherited or de novo, can be gain- or loss-of-function, and can affect one or more genes. Recent evidence indicates that brain somatic mutations contribute to several NDDs, in particular malformations of cortical development. While advances in sequencing technologies have enabled the detection of these somatic mutations, the mechanisms by which they alter brain development and function are not well understood due to limited model systems that recapitulate these events. Human brain organoids have emerged as powerful models to study the early developmental events of the human brain. Brain organoids capture the developmental progression of the human brain and contain human-enriched progenitor cell types. Advances in human stem cell and genome engineering provide an opportunity to model NDD-associated somatic mutations in brain organoids. These organoids can be tracked throughout development to understand the impact of somatic mutations on early human brain development and function. In this review, we discuss recent evidence that somatic mutations occur in the developing human brain, that they can lead to NDDs, and discuss how they could be modeled using human brain organoids.
Collapse
Affiliation(s)
- Bipan K. Deb
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, United States
| | - Helen S. Bateup
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, United States
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, United States
- Chan Zuckerberg Biohub, San Francisco, CA, United States
- *Correspondence: Helen S. Bateup
| |
Collapse
|
61
|
Bacq A, Roussel D, Bonduelle T, Zagaglia S, Maletic M, Ribierre T, Adle‐Biassette H, Marchal C, Jennesson M, An I, Picard F, Navarro V, Sisodiya SM, Baulac S. Cardiac Investigations in Sudden Unexpected Death in DEPDC5-Related Epilepsy. Ann Neurol 2022; 91:101-116. [PMID: 34693554 PMCID: PMC9299146 DOI: 10.1002/ana.26256] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Revised: 10/20/2021] [Accepted: 10/21/2021] [Indexed: 12/17/2022]
Abstract
OBJECTIVE Germline loss-of-function mutations in DEPDC5, and in its binding partners (NPRL2/3) of the mammalian target of rapamycin (mTOR) repressor GATOR1 complex, cause focal epilepsies and increase the risk of sudden unexpected death in epilepsy (SUDEP). Here, we asked whether DEPDC5 haploinsufficiency predisposes to primary cardiac defects that could contribute to SUDEP and therefore impact the clinical management of patients at high risk of SUDEP. METHODS Clinical cardiac investigations were performed in 16 patients with pathogenic variants in DEPDC5, NPRL2, or NPRL3. Two novel Depdc5 mouse strains, a human HA-tagged Depdc5 strain and a Depdc5 heterozygous knockout with a neuron-specific deletion of the second allele (Depdc5c/- ), were generated to investigate the role of Depdc5 in SUDEP and cardiac activity during seizures. RESULTS Holter, echocardiographic, and electrocardiographic (ECG) examinations provided no evidence for altered clinical cardiac function in the patient cohort, of whom 3 DEPDC5 patients succumbed to SUDEP and 6 had a family history of SUDEP. There was no cardiac injury at autopsy in a postmortem DEPDC5 SUDEP case. The HA-tagged Depdc5 mouse revealed expression of Depdc5 in the brain, heart, and lungs. Simultaneous electroencephalographic-ECG records on Depdc5c/- mice showed that spontaneous epileptic seizures resulting in a SUDEP-like event are not preceded by cardiac arrhythmia. INTERPRETATION Mouse and human data show neither structural nor functional cardiac damage that might underlie a primary contribution to SUDEP in the spectrum of DEPDC5-related epilepsies. ANN NEUROL 2022;91:101-116.
Collapse
Affiliation(s)
- Alexandre Bacq
- Sorbonne University, Paris Brain Institute (ICM), Inserm, CNRS, AP‐HP, Pitié‐Salpêtrière HospitalParisFrance
| | - Delphine Roussel
- Sorbonne University, Paris Brain Institute (ICM), Inserm, CNRS, AP‐HP, Pitié‐Salpêtrière HospitalParisFrance
| | - Thomas Bonduelle
- Sorbonne University, Paris Brain Institute (ICM), Inserm, CNRS, AP‐HP, Pitié‐Salpêtrière HospitalParisFrance
- Epilepsy and Neurology Department, Bordeaux University Hospital CenterBordeauxFrance
| | - Sara Zagaglia
- Department of Clinical and Experimental EpilepsyUniversity College London Queen Square Institute of NeurologyLondonUK
- Chalfont Centre for EpilepsyBucksUK
| | - Marina Maletic
- Sorbonne University, Paris Brain Institute (ICM), Inserm, CNRS, AP‐HP, Pitié‐Salpêtrière HospitalParisFrance
| | - Théo Ribierre
- Sorbonne University, Paris Brain Institute (ICM), Inserm, CNRS, AP‐HP, Pitié‐Salpêtrière HospitalParisFrance
| | - Homa Adle‐Biassette
- Pathological Anatomy Department, University of Paris, AP‐HP, Lariboisière Hospital, DMU, DREAM, UMR 1141, INSERMParisFrance
| | - Cécile Marchal
- Epilepsy and Neurology Department, Bordeaux University Hospital CenterBordeauxFrance
| | - Mélanie Jennesson
- Department of PediatricsAmerican Memorial Hospital, Reims University Hospital CenterReimsFrance
| | - Isabelle An
- Epileptology Unit and Reference Center of Rare Epilepsies, Pitié‐Salpêtrière Hospital, AP‐HPParisFrance
| | - Fabienne Picard
- EEG and Epilepsy Unit, Department of Clinical NeurosciencesUniversity Hospitals and Faculty of Medicine of GenevaGenevaSwitzerland
| | - Vincent Navarro
- Sorbonne University, Paris Brain Institute (ICM), Inserm, CNRS, AP‐HP, Pitié‐Salpêtrière HospitalParisFrance
- Epileptology Unit and Reference Center of Rare Epilepsies, Pitié‐Salpêtrière Hospital, AP‐HPParisFrance
| | - Sanjay M. Sisodiya
- Department of Clinical and Experimental EpilepsyUniversity College London Queen Square Institute of NeurologyLondonUK
- Chalfont Centre for EpilepsyBucksUK
| | - Stéphanie Baulac
- Sorbonne University, Paris Brain Institute (ICM), Inserm, CNRS, AP‐HP, Pitié‐Salpêtrière HospitalParisFrance
| |
Collapse
|
62
|
Jabari S, Kobow K, Pieper T, Hartlieb T, Kudernatsch M, Polster T, Bien CG, Kalbhenn T, Simon M, Hamer H, Rössler K, Feucht M, Mühlebner A, Najm I, Peixoto-Santos JE, Gil-Nagel A, Delgado RT, Aledo-Serrano A, Hou Y, Coras R, von Deimling A, Blümcke I. DNA methylation-based classification of malformations of cortical development in the human brain. Acta Neuropathol 2022; 143:93-104. [PMID: 34797422 PMCID: PMC8732912 DOI: 10.1007/s00401-021-02386-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 10/26/2021] [Accepted: 11/15/2021] [Indexed: 12/16/2022]
Abstract
Malformations of cortical development (MCD) comprise a broad spectrum of structural brain lesions frequently associated with epilepsy. Disease definition and diagnosis remain challenging and are often prone to arbitrary judgment. Molecular classification of histopathological entities may help rationalize the diagnostic process. We present a retrospective, multi-center analysis of genome-wide DNA methylation from human brain specimens obtained from epilepsy surgery using EPIC 850 K BeadChip arrays. A total of 308 samples were included in the study. In the reference cohort, 239 formalin-fixed and paraffin-embedded (FFPE) tissue samples were histopathologically classified as MCD, including 12 major subtype pathologies. They were compared to 15 FFPE samples from surgical non-MCD cortices and 11 FFPE samples from post-mortem non-epilepsy controls. We applied three different statistical approaches to decipher the DNA methylation pattern of histopathological MCD entities, i.e., pairwise comparison, machine learning, and deep learning algorithms. Our deep learning model, which represented a shallow neuronal network, achieved the highest level of accuracy. A test cohort of 43 independent surgical samples from different epilepsy centers was used to test the precision of our DNA methylation-based MCD classifier. All samples from the test cohort were accurately assigned to their disease classes by the algorithm. These data demonstrate DNA methylation-based MCD classification suitability across major histopathological entities amenable to epilepsy surgery and age groups and will help establish an integrated diagnostic classification scheme for epilepsy-associated MCD.
Collapse
Affiliation(s)
- Samir Jabari
- Department of Neuropathology, Affiliated Partner of the ERN EpiCARE, Universitätsklinikum Erlangen, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Katja Kobow
- Department of Neuropathology, Affiliated Partner of the ERN EpiCARE, Universitätsklinikum Erlangen, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany.
| | - Tom Pieper
- Center for Pediatric Neurology, Neurorehabilitation and Epileptology, Vogtareuth, Germany
| | - Till Hartlieb
- Center for Pediatric Neurology, Neurorehabilitation and Epileptology, Vogtareuth, Germany
- Research Institute, Rehabilitation, Transition, Palliation", PMU Salzburg, Salzburg, Austria
| | - Manfred Kudernatsch
- Center for Neurosurgery and Epilepsy Surgery, Schön Klinik Vogtareuth, Vogtareuth, Germany
- Research Institute, Rehabilitation, Transition, Palliation", PMU Salzburg, Salzburg, Austria
| | - Tilman Polster
- Department of Epileptology (Krankenhaus Mara), Medical School, Bielefeld University, Bielefeld, Germany
| | - Christian G Bien
- Department of Epileptology (Krankenhaus Mara), Medical School, Bielefeld University, Bielefeld, Germany
| | - Thilo Kalbhenn
- Department of Neurosurgery - Epilepsy Surgery, Evangelisches Klinikum Bethel, Universitätsklinikum OWL, Bielefeld University, Bielefeld, Germany
| | - Matthias Simon
- Department of Neurosurgery - Epilepsy Surgery, Evangelisches Klinikum Bethel, Universitätsklinikum OWL, Bielefeld University, Bielefeld, Germany
| | - Hajo Hamer
- Department of Neurology, Epilepsy Center, Universitätsklinikum Erlangen, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Karl Rössler
- Department of Neurosurgery, Universitätsklinikum Erlangen, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
- Department of Neurosurgery, Medical University Vienna, Vienna, Austria
| | - Martha Feucht
- Department of Pediatrics and Adolescent Medicine, Affiliated Partner of the ERN EpiCARE, Medical University Vienna, Vienna, Austria
| | - Angelika Mühlebner
- Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands
- Department of (Neuro) Pathology, Amsterdam UMC, Location AMC, Amsterdam, The Netherlands
| | - Imad Najm
- Charles Shor Epilepsy Center, Cleveland Clinic, Cleveland, OH, USA
- Department of Neurology, Cleveland Clinic, Cleveland, OH, USA
| | | | | | | | | | - Yanghao Hou
- Department of Neuropathology, German Cancer Research Center (DKFZ), Universitätsklinikum Heidelberg, and CCU Neuropathology, Heidelberg, Germany
- Institute of Pathology and Southwest Cancer Center, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing, China
| | - Roland Coras
- Department of Neuropathology, Affiliated Partner of the ERN EpiCARE, Universitätsklinikum Erlangen, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Andreas von Deimling
- Department of Neuropathology, German Cancer Research Center (DKFZ), Universitätsklinikum Heidelberg, and CCU Neuropathology, Heidelberg, Germany
| | - Ingmar Blümcke
- Department of Neuropathology, Affiliated Partner of the ERN EpiCARE, Universitätsklinikum Erlangen, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
| |
Collapse
|
63
|
Nguyen LH, Xu Y, Mahadeo T, Zhang L, Lin TV, Born HA, Anderson AE, Bordey A. Expression of 4E-BP1 in juvenile mice alleviates mTOR-induced neuronal dysfunction and epilepsy. Brain 2021; 145:1310-1325. [PMID: 34849602 DOI: 10.1093/brain/awab390] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 09/01/2021] [Accepted: 09/22/2021] [Indexed: 11/13/2022] Open
Abstract
Hyperactivation of the mechanistic target of rapamycin (mTOR) pathway during fetal neurodevelopment alters neuron structure and function, leading to focal malformation of cortical development (FMCD) and intractable epilepsy. Recent evidence suggests a role for dysregulated cap-dependent translation downstream of mTOR in the formation of FMCD and seizures. However, it is unknown whether modifying translation once the developmental pathologies are established can reverse neuronal abnormalities and seizures. Addressing these issues is crucial with regards to therapeutics since these neurodevelopmental disorders are predominantly diagnosed during childhood, when patients present with symptoms. Here, we report increased phosphorylation of the mTOR effector and translational repressor, 4E-BP1, in patient FMCD tissue and in a mouse model of FMCD. Using temporally regulated conditional gene expression systems, we found that expression of a constitutively active form of 4E-BP1 that resists phosphorylation by mTOR in juvenile mice reduced neuronal cytomegaly and corrected several neuronal electrophysiological alterations, including depolarized resting membrane potential, irregular firing pattern, and aberrant expression of HCN4 channels. Further, 4E-BP1 expression in juvenile FMCD mice after epilepsy onset resulted in improved cortical spectral activity and decreased spontaneous seizure frequency in adults. Overall, our study uncovered a remarkable plasticity of the juvenile brain that facilitates novel therapeutic opportunities to treat FMCD-related epilepsy during childhood with potentially long-lasting effects in adults.
Collapse
Affiliation(s)
- Lena H Nguyen
- Department of Neurosurgery, Yale University School of Medicine; New Haven, CT 06510, USA.,Department of Cellular and Molecular Physiology, Yale University School of Medicine; New Haven, CT 06510, USA
| | - Youfen Xu
- Department of Neurosurgery, Yale University School of Medicine; New Haven, CT 06510, USA
| | - Travorn Mahadeo
- Department of Neurosurgery, Yale University School of Medicine; New Haven, CT 06510, USA
| | - Longbo Zhang
- Department of Neurosurgery, Yale University School of Medicine; New Haven, CT 06510, USA
| | - Tiffany V Lin
- Department of Neurosurgery, Yale University School of Medicine; New Haven, CT 06510, USA
| | - Heather A Born
- Cain Foundation Laboratories, Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital; Houston, TX 77030, USA.,Department of Pediatrics, Baylor College of Medicine; Houston, TX 77030, USA
| | - Anne E Anderson
- Cain Foundation Laboratories, Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital; Houston, TX 77030, USA.,Department of Pediatrics, Baylor College of Medicine; Houston, TX 77030, USA
| | - Angélique Bordey
- Department of Neurosurgery, Yale University School of Medicine; New Haven, CT 06510, USA.,Department of Cellular and Molecular Physiology, Yale University School of Medicine; New Haven, CT 06510, USA
| |
Collapse
|
64
|
Ishida S, Zhao D, Sawada Y, Hiraoka Y, Mashimo T, Tanaka K. Dorsal telencephalon-specific Nprl2- and Nprl3-knockout mice: novel mouse models for GATORopathy. Hum Mol Genet 2021; 31:1519-1530. [PMID: 34965576 PMCID: PMC9071434 DOI: 10.1093/hmg/ddab337] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 09/28/2021] [Accepted: 11/12/2021] [Indexed: 11/30/2022] Open
Abstract
The most frequent genetic cause of focal epilepsies is variations in the GAP activity toward RAGs 1 complex genes DEP domain containing 5 (DEPDC5), nitrogen permease regulator 2-like protein (NPRL2) and nitrogen permease regulator 3-like protein (NPRL3). Because these variations are frequent and associated with a broad spectrum of focal epilepsies, a unique pathology categorized as GATORopathy can be conceptualized. Animal models recapitulating the clinical features of patients are essential to decipher GATORopathy. Although several genetically modified animal models recapitulate DEPDC5-related epilepsy, no models have been reported for NPRL2- or NPRL3-related epilepsies. Here, we conditionally deleted Nprl2 and Nprl3 from the dorsal telencephalon in mice [Emx1cre/+; Nprl2f/f (Nprl2-cKO) and Emx1cre/+; Nprl3f/f (Nprl3-cKO)] and compared their phenotypes with Nprl2+/−, Nprl3+/− and Emx1cre/+; Depdc5f/f (Depdc5-cKO) mice. Nprl2-cKO and Nprl3-cKO mice recapitulated the major abnormal features of patients—spontaneous seizures, and dysmorphic enlarged neuronal cells with increased mechanistic target of rapamycin complex 1 signaling—similar to Depdc5-cKO mice. Chronic postnatal rapamycin administration dramatically prolonged the survival period and inhibited seizure occurrence but not enlarged neuronal cells in Nprl2-cKO and Nprl3-cKO mice. However, the benefit of rapamycin after withdrawal was less durable in Nprl2- and Nprl3-cKO mice compared with Depdc5-cKO mice. Further studies using these conditional knockout mice will be useful for understanding GATORopathy and for the identification of novel therapeutic targets.
Collapse
Affiliation(s)
- Saeko Ishida
- Laboratory of Molecular Neuroscience, Medical Research Institute (MRI), Tokyo Medical and Dental University (TMDU), Tokyo, 113-8510, Japan
- Division of Animal Genetics, Laboratory Animal Research Center, The Institute of Medical Science, The University of Tokyo, Tokyo, 108-8639, Japan
| | - Di Zhao
- Laboratory of Molecular Neuroscience, Medical Research Institute (MRI), Tokyo Medical and Dental University (TMDU), Tokyo, 113-8510, Japan
- Division of Animal Genetics, Laboratory Animal Research Center, The Institute of Medical Science, The University of Tokyo, Tokyo, 108-8639, Japan
| | - Yuta Sawada
- Laboratory of Molecular Neuroscience, Medical Research Institute (MRI), Tokyo Medical and Dental University (TMDU), Tokyo, 113-8510, Japan
| | - Yuichi Hiraoka
- Laboratory of Molecular Neuroscience, Medical Research Institute (MRI), Tokyo Medical and Dental University (TMDU), Tokyo, 113-8510, Japan
- Laboratory of Genome Editing for Biomedical Research, MRI, TMDU, Tokyo, 101-0062, Japan
| | - Tomoji Mashimo
- Division of Animal Genetics, Laboratory Animal Research Center, The Institute of Medical Science, The University of Tokyo, Tokyo, 108-8639, Japan
| | - Kohichi Tanaka
- Laboratory of Molecular Neuroscience, Medical Research Institute (MRI), Tokyo Medical and Dental University (TMDU), Tokyo, 113-8510, Japan
- Center for Brain Integration Research (CBIR), TMDU, Tokyo, 113-8510, Japan
| |
Collapse
|
65
|
Patodia S, Somani A, Thom M. Review: Neuropathology findings in autonomic brain regions in SUDEP and future research directions. Auton Neurosci 2021; 235:102862. [PMID: 34411885 PMCID: PMC8455454 DOI: 10.1016/j.autneu.2021.102862] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 07/16/2021] [Accepted: 07/24/2021] [Indexed: 12/21/2022]
Abstract
Autonomic dysfunction is implicated from clinical, neuroimaging and experimental studies in sudden and unexpected death in epilepsy (SUDEP). Neuropathological analysis in SUDEP series enable exploration of acquired, seizure-related cellular adaptations in autonomic and brainstem autonomic centres of relevance to dysfunction in the peri-ictal period. Alterations in SUDEP compared to control groups have been identified in the ventrolateral medulla, amygdala, hippocampus and central autonomic regions. These involve neuropeptidergic, serotonergic and adenosine systems, as well as specific regional astroglial and microglial populations, as potential neuronal modulators, orchestrating autonomic dysfunction. Future research studies need to extend to clinically and genetically characterized epilepsies, to explore if common or distinct pathways of autonomic dysfunction mediate SUDEP. The ultimate objective of SUDEP research is the identification of disease biomarkers for at risk patients, to improve post-mortem recognition and disease categorisation, but ultimately, for exposing potential treatment targets of pharmacologically modifiable and reversible cellular alterations.
Collapse
Affiliation(s)
- Smriti Patodia
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Alyma Somani
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Maria Thom
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK.
| |
Collapse
|
66
|
Vasic V, Jones MSO, Haslinger D, Knaus LS, Schmeisser MJ, Novarino G, Chiocchetti AG. Translating the Role of mTOR- and RAS-Associated Signalopathies in Autism Spectrum Disorder: Models, Mechanisms and Treatment. Genes (Basel) 2021; 12:genes12111746. [PMID: 34828352 PMCID: PMC8624393 DOI: 10.3390/genes12111746] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 10/25/2021] [Accepted: 10/28/2021] [Indexed: 12/23/2022] Open
Abstract
Mutations affecting mTOR or RAS signaling underlie defined syndromes (the so-called mTORopathies and RASopathies) with high risk for Autism Spectrum Disorder (ASD). These syndromes show a broad variety of somatic phenotypes including cancers, skin abnormalities, heart disease and facial dysmorphisms. Less well studied are the neuropsychiatric symptoms such as ASD. Here, we assess the relevance of these signalopathies in ASD reviewing genetic, human cell model, rodent studies and clinical trials. We conclude that signalopathies have an increased liability for ASD and that, in particular, ASD individuals with dysmorphic features and intellectual disability (ID) have a higher chance for disruptive mutations in RAS- and mTOR-related genes. Studies on rodent and human cell models confirm aberrant neuronal development as the underlying pathology. Human studies further suggest that multiple hits are necessary to induce the respective phenotypes. Recent clinical trials do only report improvements for comorbid conditions such as epilepsy or cancer but not for behavioral aspects. Animal models show that treatment during early development can rescue behavioral phenotypes. Taken together, we suggest investigating the differential roles of mTOR and RAS signaling in both human and rodent models, and to test drug treatment both during and after neuronal development in the available model systems.
Collapse
Affiliation(s)
- Verica Vasic
- Institute for Microscopic Anatomy and Neurobiology, University Medical Center of the Johannes Gutenberg-University, 55131 Mainz, Germany; (V.V.); (M.J.S.)
| | - Mattson S. O. Jones
- Autism Therapy and Research Center of Excellence, Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University Hospital Frankfurt, 60528 Frankfurt am Main, Germany; (M.S.O.J.); (D.H.)
- Center for Personalized Translational Epilepsy Research (CePTER), Goethe University Frankfurt, 60528 Frankfurt am Main, Germany
| | - Denise Haslinger
- Autism Therapy and Research Center of Excellence, Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University Hospital Frankfurt, 60528 Frankfurt am Main, Germany; (M.S.O.J.); (D.H.)
- Institute of Science and Technology (IST) Austria, 3400 Klosterneuburg, Austria; (L.S.K.); (G.N.)
| | - Lisa S. Knaus
- Institute of Science and Technology (IST) Austria, 3400 Klosterneuburg, Austria; (L.S.K.); (G.N.)
| | - Michael J. Schmeisser
- Institute for Microscopic Anatomy and Neurobiology, University Medical Center of the Johannes Gutenberg-University, 55131 Mainz, Germany; (V.V.); (M.J.S.)
- Focus Program Translational Neurosciences (FTN), University Medical Center of the Johannes Gutenberg-University, 55131 Mainz, Germany
| | - Gaia Novarino
- Institute of Science and Technology (IST) Austria, 3400 Klosterneuburg, Austria; (L.S.K.); (G.N.)
| | - Andreas G. Chiocchetti
- Autism Therapy and Research Center of Excellence, Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University Hospital Frankfurt, 60528 Frankfurt am Main, Germany; (M.S.O.J.); (D.H.)
- Center for Personalized Translational Epilepsy Research (CePTER), Goethe University Frankfurt, 60528 Frankfurt am Main, Germany
- Correspondence: ; Tel.: +49-69-6301-80658
| |
Collapse
|
67
|
Guerrini R, Balestrini S, Wirrell EC, Walker MC. Monogenic Epilepsies: Disease Mechanisms, Clinical Phenotypes, and Targeted Therapies. Neurology 2021; 97:817-831. [PMID: 34493617 PMCID: PMC10336826 DOI: 10.1212/wnl.0000000000012744] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 08/18/2021] [Indexed: 02/05/2023] Open
Abstract
A monogenic etiology can be identified in up to 40% of people with severe epilepsy. To address earlier and more appropriate treatment strategies, clinicians are required to know the implications that specific genetic causes might have on pathophysiology, natural history, comorbidities, and treatment choices. In this narrative review, we summarize concepts on the genetic epilepsies based on the underlying pathophysiologic mechanisms and present the current knowledge on treatment options based on evidence provided by controlled trials or studies with lower classification of evidence. Overall, evidence robust enough to guide antiseizure medication (ASM) choices in genetic epilepsies remains limited to the more frequent conditions for which controlled trials and observational studies have been possible. Most monogenic disorders are very rare and ASM choices for them are still based on inferences drawn from observational studies and early, often anecdotal, experiences with precision therapies. Precision medicine remains applicable to only a narrow number of patients with monogenic epilepsies and may target only part of the actual functional defects. Phenotypic heterogeneity is remarkable, and some genetic mutations activate epileptogenesis through their developmental effects, which may not be reversed postnatally. Other genes seem to have pure functional consequences on excitability, acting through either loss- or gain-of-function effects, and these may have opposite treatment implications. In addition, the functional consequences of missense mutations may be difficult to predict, making precision treatment approaches considerably more complex than estimated by deterministic interpretations. Knowledge of genetic etiologies can influence the approach to surgical treatment of focal epilepsies. Identification of germline mutations in specific genes contraindicates surgery while mutations in other genes do not. Identification, quantification, and functional characterization of specific somatic mutations before surgery using CSF liquid biopsy or after surgery in brain specimens will likely be integrated in planning surgical strategies and reintervention after a first unsuccessful surgery as initial evidence suggests that mutational load may correlate with the epileptogenic zone. Promising future directions include gene manipulation by DNA or mRNA targeting; although most are still far from clinical use, some are in early phase clinical development.
Collapse
Affiliation(s)
- Renzo Guerrini
- From the Neuroscience Department (R.G., S.B.), Meyer Children's Hospital-University of Florence, Italy; Department of Clinical and Experimental Epilepsy (S.B., M.C.W.), UCL Queen Square Institute of Neurology, London; Chalfont Centre for Epilepsy (S.B.), Buckinghamshire, UK; and Divisions of Child and Adolescent Neurology and Epilepsy (E.C.W.), Department of Neurology, Mayo Clinic, Rochester, MN.
| | - Simona Balestrini
- From the Neuroscience Department (R.G., S.B.), Meyer Children's Hospital-University of Florence, Italy; Department of Clinical and Experimental Epilepsy (S.B., M.C.W.), UCL Queen Square Institute of Neurology, London; Chalfont Centre for Epilepsy (S.B.), Buckinghamshire, UK; and Divisions of Child and Adolescent Neurology and Epilepsy (E.C.W.), Department of Neurology, Mayo Clinic, Rochester, MN
| | - Elaine C Wirrell
- From the Neuroscience Department (R.G., S.B.), Meyer Children's Hospital-University of Florence, Italy; Department of Clinical and Experimental Epilepsy (S.B., M.C.W.), UCL Queen Square Institute of Neurology, London; Chalfont Centre for Epilepsy (S.B.), Buckinghamshire, UK; and Divisions of Child and Adolescent Neurology and Epilepsy (E.C.W.), Department of Neurology, Mayo Clinic, Rochester, MN
| | - Matthew C Walker
- From the Neuroscience Department (R.G., S.B.), Meyer Children's Hospital-University of Florence, Italy; Department of Clinical and Experimental Epilepsy (S.B., M.C.W.), UCL Queen Square Institute of Neurology, London; Chalfont Centre for Epilepsy (S.B.), Buckinghamshire, UK; and Divisions of Child and Adolescent Neurology and Epilepsy (E.C.W.), Department of Neurology, Mayo Clinic, Rochester, MN
| |
Collapse
|
68
|
Neocortical development and epilepsy: insights from focal cortical dysplasia and brain tumours. Lancet Neurol 2021; 20:943-955. [PMID: 34687638 DOI: 10.1016/s1474-4422(21)00265-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 07/14/2021] [Accepted: 08/05/2021] [Indexed: 01/16/2023]
Abstract
During the past decade, there have been considerable advances in understanding of the genetic and morphogenic processes underlying cortical malformations and developmental brain tumours. Focal malformations are caused by somatic (postzygotic) variants in genes related to cell growth (ie, in the mTOR pathway in focal cortical dysplasia type 2), which are acquired in neuronal progenitors during neurodevelopment. In comparison, developmental brain tumours result from somatic variants in genes related to cell proliferation (eg, in the MAP-kinase pathway in ganglioglioma), which affect proliferating glioneuronal precursors. The timing of the genetic event and the specific gene involved during neurodevelopment will drive the nature and size of the lesion, whether it is a developmental malformation or a brain tumour. There is also emerging evidence that epigenetic processes underlie a molecular memory in epileptogenesis. This knowledge will together facilitate understanding of why and how patients with these lesions have epilepsy, and could form a basis for a move towards precision medicine for this challenging cohort of patients.
Collapse
|
69
|
Moloney PB, Cavalleri GL, Delanty N. Epilepsy in the mTORopathies: opportunities for precision medicine. Brain Commun 2021; 3:fcab222. [PMID: 34632383 PMCID: PMC8495134 DOI: 10.1093/braincomms/fcab222] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/23/2021] [Accepted: 08/30/2021] [Indexed: 01/16/2023] Open
Abstract
The mechanistic target of rapamycin signalling pathway serves as a ubiquitous regulator of cell metabolism, growth, proliferation and survival. The main cellular activity of the mechanistic target of rapamycin cascade funnels through mechanistic target of rapamycin complex 1, which is inhibited by rapamycin, a macrolide compound produced by the bacterium Streptomyces hygroscopicus. Pathogenic variants in genes encoding upstream regulators of mechanistic target of rapamycin complex 1 cause epilepsies and neurodevelopmental disorders. Tuberous sclerosis complex is a multisystem disorder caused by mutations in mechanistic target of rapamycin regulators TSC1 or TSC2, with prominent neurological manifestations including epilepsy, focal cortical dysplasia and neuropsychiatric disorders. Focal cortical dysplasia type II results from somatic brain mutations in mechanistic target of rapamycin pathway activators MTOR, AKT3, PIK3CA and RHEB and is a major cause of drug-resistant epilepsy. DEPDC5, NPRL2 and NPRL3 code for subunits of the GTPase-activating protein (GAP) activity towards Rags 1 complex (GATOR1), the principal amino acid-sensing regulator of mechanistic target of rapamycin complex 1. Germline pathogenic variants in GATOR1 genes cause non-lesional focal epilepsies and epilepsies associated with malformations of cortical development. Collectively, the mTORopathies are characterized by excessive mechanistic target of rapamycin pathway activation and drug-resistant epilepsy. In the first large-scale precision medicine trial in a genetically mediated epilepsy, everolimus (a synthetic analogue of rapamycin) was effective at reducing seizure frequency in people with tuberous sclerosis complex. Rapamycin reduced seizures in rodent models of DEPDC5-related epilepsy and focal cortical dysplasia type II. This review outlines a personalized medicine approach to the management of epilepsies in the mTORopathies. We advocate for early diagnostic sequencing of mechanistic target of rapamycin pathway genes in drug-resistant epilepsy, as identification of a pathogenic variant may point to an occult dysplasia in apparently non-lesional epilepsy or may uncover important prognostic information including, an increased risk of sudden unexpected death in epilepsy in the GATORopathies or favourable epilepsy surgery outcomes in focal cortical dysplasia type II due to somatic brain mutations. Lastly, we discuss the potential therapeutic application of mechanistic target of rapamycin inhibitors for drug-resistant seizures in GATOR1-related epilepsies and focal cortical dysplasia type II.
Collapse
Affiliation(s)
- Patrick B Moloney
- FutureNeuro, the Science Foundation Ireland Research Centre for Chronic and Rare Neurological Diseases, Royal College of Surgeons in Ireland, Dublin, D02 VN51, Ireland
| | - Gianpiero L Cavalleri
- FutureNeuro, the Science Foundation Ireland Research Centre for Chronic and Rare Neurological Diseases, Royal College of Surgeons in Ireland, Dublin, D02 VN51, Ireland
| | - Norman Delanty
- FutureNeuro, the Science Foundation Ireland Research Centre for Chronic and Rare Neurological Diseases, Royal College of Surgeons in Ireland, Dublin, D02 VN51, Ireland
| |
Collapse
|
70
|
Loissell-Baltazar YA, Dokudovskaya S. SEA and GATOR 10 Years Later. Cells 2021; 10:cells10102689. [PMID: 34685669 PMCID: PMC8534245 DOI: 10.3390/cells10102689] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 09/30/2021] [Accepted: 10/03/2021] [Indexed: 12/17/2022] Open
Abstract
The SEA complex was described for the first time in yeast Saccharomyces cerevisiae ten years ago, and its human homologue GATOR complex two years later. During the past decade, many advances on the SEA/GATOR biology in different organisms have been made that allowed its role as an essential upstream regulator of the mTORC1 pathway to be defined. In this review, we describe these advances in relation to the identification of multiple functions of the SEA/GATOR complex in nutrient response and beyond and highlight the consequence of GATOR mutations in cancer and neurodegenerative diseases.
Collapse
|
71
|
Ye Z, Bennett MF, Bahlo M, Scheffer IE, Berkovic SF, Perucca P, Hildebrand MS. Cutting edge approaches to detecting brain mosaicism associated with common focal epilepsies: implications for diagnosis and potential therapies. Expert Rev Neurother 2021; 21:1309-1316. [PMID: 34519595 DOI: 10.1080/14737175.2021.1981288] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
INTRODUCTION Mosaic variants arising in brain tissue are increasingly being recognized as a hidden cause of focal epilepsy. This knowledge gain has been driven by new, highly sensitive genetic technologies and genome-wide analysis of brain tissue from surgical resection or autopsy in a small proportion of patients with focal epilepsy. Recently reported novel strategies to detect mosaic variants limited to brain have exploited trace brain DNA obtained from cerebrospinal fluid liquid biopsies or stereo-electroencephalography electrodes. AREAS COVERED The authors review the data on these innovative approaches published in PubMed before 12 June 2021, discuss the challenges associated with their application, and describe how they are likely to improve detection of mosaic variants to provide new molecular diagnoses and therapeutic targets for focal epilepsy, with potential utility in other nonmalignant neurological disorders. EXPERT OPINION These cutting-edge approaches may reveal the hidden genetic etiology of focal epilepsies and provide guidance for precision medicine.
Collapse
Affiliation(s)
- Zimeng Ye
- Department of Medicine (Austin Health), Epilepsy Research Centre, University of Melbourne, Heidelberg, Australia
| | - Mark F Bennett
- Department of Medicine (Austin Health), Epilepsy Research Centre, University of Melbourne, Heidelberg, Australia.,Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Melanie Bahlo
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Ingrid E Scheffer
- Department of Medicine (Austin Health), Epilepsy Research Centre, University of Melbourne, Heidelberg, Australia.,Neuroscience Research Group, Murdoch Children's Research Institute, Parkville, Australia.,Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Parkville, Australia.,Department of Neurology, Comprehensive Epilepsy Program, Austin Health, Heidelberg, Australia
| | - Samuel F Berkovic
- Department of Medicine (Austin Health), Epilepsy Research Centre, University of Melbourne, Heidelberg, Australia.,Department of Neurology, Comprehensive Epilepsy Program, Austin Health, Heidelberg, Australia
| | - Piero Perucca
- Department of Medicine (Austin Health), Epilepsy Research Centre, University of Melbourne, Heidelberg, Australia.,Department of Neurology, Comprehensive Epilepsy Program, Austin Health, Heidelberg, Australia.,Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Australia.,Department of Neurology, Alfred Health, Melbourne, Australia.,Department of Neurology, The Royal Melbourne Hospital, Parkville, Australia
| | - Michael S Hildebrand
- Department of Medicine (Austin Health), Epilepsy Research Centre, University of Melbourne, Heidelberg, Australia.,Neuroscience Research Group, Murdoch Children's Research Institute, Parkville, Australia
| |
Collapse
|
72
|
Klofas LK, Short BP, Zhou C, Carson RP. Prevention of premature death and seizures in a Depdc5 mouse epilepsy model through inhibition of mTORC1. Hum Mol Genet 2021; 29:1365-1377. [PMID: 32280987 DOI: 10.1093/hmg/ddaa068] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 03/31/2020] [Accepted: 04/06/2020] [Indexed: 11/13/2022] Open
Abstract
Mutations in DEP domain containing 5 (DEPDC5) are increasingly appreciated as one of the most common causes of inherited focal epilepsy. Epilepsies due to DEPDC5 mutations are often associated with brain malformations, tend to be drug-resistant, and have been linked to an increased risk of sudden unexplained death in epilepsy (SUDEP). Generation of epilepsy models to define mechanisms of epileptogenesis remains vital for future therapies. Here, we describe a novel mouse model of Depdc5 deficiency with a severe epilepsy phenotype, generated by conditional deletion of Depdc5 in dorsal telencephalic neuroprogenitor cells. In contrast to control and heterozygous mice, Depdc5-Emx1-Cre conditional knockout (CKO) mice demonstrated macrocephaly, spontaneous seizures and premature death. Consistent with increased mTORC1 activation, targeted neurons were enlarged and both neurons and astrocytes demonstrated increased S6 phosphorylation. Electrophysiologic characterization of miniature inhibitory post-synaptic currents in excitatory neurons was consistent with impaired post-synaptic response to GABAergic input, suggesting a potential mechanism for neuronal hyperexcitability. mTORC1 inhibition with rapamycin significantly improved survival of CKO animals and prevented observed seizures, including for up to 40 days following rapamycin withdrawal. These data not only support a primary role for mTORC1 hyperactivation in epilepsy following homozygous loss of Depdc5, but also suggest a developmental window for treatment which may have a durable benefit for some time even after withdrawal.
Collapse
Affiliation(s)
- Lindsay K Klofas
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37232, USA
| | - Brittany P Short
- Division of Pediatric Neurology, Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Chengwen Zhou
- Department of Neurology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Robert P Carson
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37232, USA.,Division of Pediatric Neurology, Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA.,Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| |
Collapse
|
73
|
Abstract
The presence of unprovoked, recurrent seizures, particularly when drug resistant and associated with cognitive and behavioral deficits, warrants investigation for an underlying genetic cause. This article provides an overview of the major classes of genes associated with epilepsy phenotypes divided into functional categories along with the recommended work-up and therapeutic considerations. Gene discovery in epilepsy supports counseling and anticipatory guidance but also opens the door for precision medicine guiding therapy with a focus on those with disease-modifying effects.
Collapse
Affiliation(s)
- Luis A Martinez
- Department of Pediatrics, Section of Pediatric Neurology and Developmental Neuroscience, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, 1250 Moursund Drive, Houston, TX 77030, USA
| | - Yi-Chen Lai
- Department of Pediatrics, Section of Pediatric Critical Care Medicine, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, 1250 Moursund Drive, Houston, TX 77030, USA
| | - J Lloyd Holder
- Department of Pediatrics, Section of Pediatric Neurology and Developmental Neuroscience, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, 1250 Moursund Drive, Houston, TX 77030, USA
| | - Anne E Anderson
- Department of Pediatrics, Section of Pediatric Neurology and Developmental Neuroscience, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, 1250 Moursund Drive, Houston, TX 77030, USA.
| |
Collapse
|
74
|
Koh HY, Jang J, Ju SH, Kim R, Cho GB, Kim DS, Sohn JW, Paik SB, Lee JH. Non-Cell Autonomous Epileptogenesis in Focal Cortical Dysplasia. Ann Neurol 2021; 90:285-299. [PMID: 34180075 DOI: 10.1002/ana.26149] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 06/24/2021] [Accepted: 06/25/2021] [Indexed: 01/01/2023]
Abstract
OBJECTIVE Low-level somatic mosaicism in the brain has been shown to be a major genetic cause of intractable focal epilepsy. However, how a relatively few mutation-carrying neurons are able to induce epileptogenesis at the local network level remains poorly understood. METHODS To probe the origin of epileptogenesis, we measured the excitability of neurons with MTOR mutation and nearby nonmutated neurons recorded by whole-cell patch-clamp and array-based electrodes comparing the topographic distribution of mutation. Computational simulation is used to understand neural network-level changes based on electrophysiological properties. To examine the underlying mechanism, we measured inhibitory and excitatory synaptic inputs in mutated neurons and nearby neurons by electrophysiological and histological methods using the mouse model and postoperative human brain tissue for cortical dysplasia. To explain non-cell-autonomous hyperexcitability, an inhibitor of adenosine kinase was injected into mice to enhance adenosine signaling and to mitigate hyperactivity of nearby nonmutated neurons. RESULTS We generated mice with a low-level somatic mutation in MTOR presenting spontaneous seizures. The seizure-triggering hyperexcitability originated from nonmutated neurons near mutation-carrying neurons, which proved to be less excitable than nonmutated neurons. Interestingly, the net balance between excitatory and inhibitory synaptic inputs onto mutated neurons remained unchanged. Additionally, we found that inhibition of adenosine kinase, which affects adenosine metabolism and neuronal excitability, reduced the hyperexcitability of nonmutated neurons. INTERPRETATION This study shows that neurons carrying somatic mutations in MTOR lead to focal epileptogenesis via non-cell-autonomous hyperexcitability of nearby nonmutated neurons. ANN NEUROL 2021;90:285-299.
Collapse
Affiliation(s)
- Hyun Yong Koh
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Jaeson Jang
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Sang Hyeon Ju
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Ryunhee Kim
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Gyu-Bon Cho
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Dong Seok Kim
- Department of Neurosurgery, Pediatric Epilepsy Clinics, Brain Korea 21 Project for Medical Science, Severance Children's Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Jong-Woo Sohn
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Se-Bum Paik
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea.,Program of Brain and Cognitive Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Jeong Ho Lee
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea.,SoVarGen, Daejeon, Republic of Korea
| |
Collapse
|
75
|
Nguyen LH, Bordey A. Corrigendum: Convergent and Divergent Mechanisms of Epileptogenesis in mTORopathies. Front Neuroanat 2021; 15:715363. [PMID: 34295225 PMCID: PMC8290855 DOI: 10.3389/fnana.2021.715363] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 05/28/2021] [Indexed: 01/16/2023] Open
Affiliation(s)
- Lena H Nguyen
- Department of Neurosurgery, Yale School of Medicine, Yale University, New Haven, CT, United States.,Department of Cellular & Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, United States
| | - Angélique Bordey
- Department of Neurosurgery, Yale School of Medicine, Yale University, New Haven, CT, United States.,Department of Cellular & Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, United States
| |
Collapse
|
76
|
Kim MH, Kim IB, Lee J, Cha DH, Park SM, Kim JH, Kim R, Park JS, An Y, Kim K, Kim S, Webster MJ, Kim S, Lee JH. Low-Level Brain Somatic Mutations Are Implicated in Schizophrenia. Biol Psychiatry 2021; 90:35-46. [PMID: 33867114 DOI: 10.1016/j.biopsych.2021.01.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 01/08/2021] [Accepted: 01/25/2021] [Indexed: 12/12/2022]
Abstract
BACKGROUND Somatic mutations arising from the brain have recently emerged as significant contributors to neurodevelopmental disorders, including childhood intractable epilepsy and cortical malformations. However, whether brain somatic mutations are implicated in schizophrenia (SCZ) is not well established. METHODS We performed deep whole exome sequencing (average read depth > 550×) of matched dorsolateral prefrontal cortex and peripheral tissues from 27 patients with SCZ and 31 age-matched control individuals, followed by comprehensive and strict analysis of somatic mutations, including mutagenesis signature, substitution patterns, and involved pathways. In particular, we explored the impact of deleterious mutations in GRIN2B through primary neural culture. RESULTS We identified an average of 4.9 and 5.6 somatic mutations per exome per brain in patients with SCZ and control individuals, respectively. These mutations presented with average variant allele frequencies of 8.0% in patients with SCZ and 7.6% in control individuals. Although mutational profiles, such as the number and type of mutations, showed no significant difference between patients with SCZ and control individuals, somatic mutations in SCZ brains were significantly enriched for SCZ-related pathways, including dopamine receptor, glutamate receptor, and long-term potentiation pathways. Furthermore, we showed that brain somatic mutations in GRIN2B (encoding glutamate ionotropic NMDA receptor subunit 2B), which were found in two patients with SCZ, disrupted the location of GRIN2B across the surface of dendrites among primary cultured neurons. CONCLUSIONS Taken together, this study shows that brain somatic mutations are associated with the pathogenesis of SCZ.
Collapse
Affiliation(s)
- Myeong-Heui Kim
- Graduate School of Medical Science and Engineering, Korea Advanced Institute for Science and Technology, Daejeon, Republic of Korea
| | - Il Bin Kim
- Graduate School of Medical Science and Engineering, Korea Advanced Institute for Science and Technology, Daejeon, Republic of Korea; Department of Psychiatry, Hanyang University Guri Hospital, Guri, Republic of Korea
| | - Junehawk Lee
- Center for Computational Science Platform, National Institute of Supercomputing and Networking, Korea Institute of Science and Technology Information, Daejeon, Republic of Korea
| | - Do Hyeon Cha
- Graduate School of Medical Science and Engineering, Korea Advanced Institute for Science and Technology, Daejeon, Republic of Korea
| | - Sang Min Park
- Graduate School of Medical Science and Engineering, Korea Advanced Institute for Science and Technology, Daejeon, Republic of Korea
| | - Ja Hye Kim
- Graduate School of Medical Science and Engineering, Korea Advanced Institute for Science and Technology, Daejeon, Republic of Korea
| | - Ryunhee Kim
- Graduate School of Medical Science and Engineering, Korea Advanced Institute for Science and Technology, Daejeon, Republic of Korea
| | - Jun Sung Park
- Graduate School of Medical Science and Engineering, Korea Advanced Institute for Science and Technology, Daejeon, Republic of Korea; European Bioinformatics Institute, Hinxton, Cambridgeshire, United Kingdom
| | - Yohan An
- Graduate School of Medical Science and Engineering, Korea Advanced Institute for Science and Technology, Daejeon, Republic of Korea
| | - Kyungdeok Kim
- Department of Biological Sciences, Korea Advanced Institute for Science and Technology, Daejeon, Republic of Korea
| | - Seyeon Kim
- Graduate School of Medical Science and Engineering, Korea Advanced Institute for Science and Technology, Daejeon, Republic of Korea
| | - Maree J Webster
- Stanley Medical Research Institute, Laboratory of Brain Research, Rockville, Maryland
| | - Sanghyeon Kim
- Stanley Medical Research Institute, Laboratory of Brain Research, Rockville, Maryland.
| | - Jeong Ho Lee
- Graduate School of Medical Science and Engineering, Korea Advanced Institute for Science and Technology, Daejeon, Republic of Korea; SoVarGen Inc., Daejeon, Republic of Korea.
| |
Collapse
|
77
|
Kobow K, Baulac S, von Deimling A, Lee JH. Molecular diagnostics in drug-resistant focal epilepsy define new disease entities. Brain Pathol 2021; 31:e12963. [PMID: 34196984 PMCID: PMC8412082 DOI: 10.1111/bpa.12963] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 03/31/2021] [Indexed: 01/16/2023] Open
Abstract
Structural brain lesions, including the broad range of malformations of cortical development (MCD) and glioneuronal tumors, are among the most common causes of drug-resistant focal epilepsy. Epilepsy surgery can provide a curative treatment option in respective patients. The currently available pre-surgical multi-modal diagnostic armamentarium includes high- and ultra-high resolution magnetic resonance imaging (MRI) and intracerebral EEG to identify a focal structural brain lesion as epilepsy underlying etiology. However, specificity and accuracy in diagnosing the type of lesion have proven to be limited. Moreover, the diagnostic process does not stop with the decision for surgery. The neuropathological diagnosis remains the gold standard for disease classification and patient stratification, but is particularly complex with high inter-observer variability. Here, the identification of lesion-specific mosaic variants together with epigenetic profiling of lesional brain tissue became new tools to more reliably identify disease entities. In this review, we will discuss how the paradigm shifts from histopathology toward an integrated diagnostic approach in cancer and the more recent development of the DNA methylation-based brain tumor classifier have started to influence epilepsy diagnostics. Some examples will be highlighted showing how the diagnosis and our mechanistic understanding of difficult to classify structural brain lesions associated with focal epilepsy has improved with molecular genetic data being considered in decision making.
Collapse
Affiliation(s)
- Katja Kobow
- Department of NeuropathologyUniversitätsklinikum ErlangenFriedrich‐Alexander‐University of Erlangen‐Nürnberg (FAU)ErlangenGermany
| | - Stéphanie Baulac
- Institut du Cerveau—Paris Brain Institute—ICMInsermCNRSSorbonne UniversitéParisFrance
| | - Andreas von Deimling
- Department of NeuropathologyUniversitätsklinikum HeidelbergHeidelbergGermany
- CCU NeuropathologyGerman Cancer Research Center (DKFZ)HeidelbergGermany
| | - Jeong Ho Lee
- Graduate School of Medical Science and EngineeringKAISTDaejeonKorea
- SoVarGen, IncDaejeonRepublic of Korea
| |
Collapse
|
78
|
D'Gama AM, Poduri A. Precision Therapy for Epilepsy Related to Brain Malformations. Neurotherapeutics 2021; 18:1548-1563. [PMID: 34608615 PMCID: PMC8608994 DOI: 10.1007/s13311-021-01122-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/04/2021] [Indexed: 02/04/2023] Open
Abstract
Malformations of cortical development (MCDs) represent a range of neurodevelopmental disorders that are collectively common causes of developmental delay and epilepsy, especially refractory childhood epilepsy. Initial treatment with antiseizure medications is empiric, and consideration of surgery is the standard of care for eligible patients with medically refractory epilepsy. In the past decade, advances in next generation sequencing technologies have accelerated progress in understanding the genetic etiologies of MCDs, and precision therapies for focal MCDs are emerging. Notably, mutations that lead to abnormal activation of the mammalian target of rapamycin (mTOR) pathway, which provides critical control of cell growth and proliferation, have emerged as a common cause of malformations. These include tuberous sclerosis complex (TSC), hemimegalencephaly (HME), and some types of focal cortical dysplasia (FCD). TSC currently represents the best example for the pathway from gene discovery to relatively safe and efficacious targeted therapy for epilepsy related to MCDs. Based on extensive pre-clinical and clinical data, the mTOR inhibitor everolimus is currently approved for the treatment of focal refractory seizures in patients with TSC. Although clinical studies are just emerging for FCD and HME, we believe the next decade will bring significant advancements in precision therapies for epilepsy related to these and other MCDs.
Collapse
Affiliation(s)
- Alissa M D'Gama
- Divisions of Newborn Medicine and Genetics and Genomics, Department of Pediatrics, Boston Children's Hospital, Boston, MA, USA
- Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital, Boston, MA, USA
- Departments of Neurology and Pediatrics, Harvard Medical School, Boston, MA, USA
- Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Annapurna Poduri
- Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital, Boston, MA, USA.
- Departments of Neurology and Pediatrics, Harvard Medical School, Boston, MA, USA.
- Broad Institute of Harvard and MIT, Cambridge, MA, USA.
| |
Collapse
|
79
|
Neuroinflammation: A Signature or a Cause of Epilepsy? Int J Mol Sci 2021; 22:ijms22136981. [PMID: 34209535 PMCID: PMC8267969 DOI: 10.3390/ijms22136981] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 06/11/2021] [Accepted: 06/23/2021] [Indexed: 12/21/2022] Open
Abstract
Epilepsy can be both a primary pathology and a secondary effect of many neurological conditions. Many papers show that neuroinflammation is a product of epilepsy, and that in pathological conditions characterized by neuroinflammation, there is a higher probability to develop epilepsy. However, the bidirectional mechanism of the reciprocal interaction between epilepsy and neuroinflammation remains to be fully understood. Here, we attempt to explore and discuss the relationship between epilepsy and inflammation in some paradigmatic neurological and systemic disorders associated with epilepsy. In particular, we have chosen one representative form of epilepsy for each one of its actual known etiologies. A better understanding of the mechanistic link between neuroinflammation and epilepsy would be important to improve subject-based therapies, both for prophylaxis and for the treatment of epilepsy.
Collapse
|
80
|
Zhang X, Huang Z, Liu J, Li M, Zhao X, Ye J, Wang Y. Phenotypic and Genotypic Characterization of DEPDC5-Related Familial Focal Epilepsy: Case Series and Literature Review. Front Neurol 2021; 12:641019. [PMID: 34239491 PMCID: PMC8258162 DOI: 10.3389/fneur.2021.641019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Accepted: 04/21/2021] [Indexed: 01/05/2023] Open
Abstract
Mutations in the disheveled, Egl-10 and domain-containing protein 5 (DEPDC5) recently have been identified as a common cause of focal epilepsy syndromes. The association between phenotype and genotype of DEPDC5 mutation has not been adequately characterized. We studied four families with familial focal epilepsy carrying DEPDC5 mutations. Four novel DEPDC5 mutations were identified by next-generation sequencing, including two missense mutations (c.1729 >A and c.3260G>A), one splicing mutation (c.280-1G>A), and one frameshift mutation (c.515_516delinsT). We found that patients carrying different DEPDC5 mutation have different clinical manifestations. Incomplete penetrance is a prominent feature of DEPDC5-related epilepsy, with the rate of penetrance ranging from 25 to 100%. About 21.4% of patients with DEPDC5-related familial focal epilepsy are refractory to treatments. We further reviewed the correlation of genotype and phenotype in all previous literature regarding DEPDC5-related epilepsy. Our study suggested that the type of DEPDC5 mutation might provide important information for the prognosis evaluation.
Collapse
Affiliation(s)
- Xuan Zhang
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China.,Beijing Key Laboratory of Neuromodulation, Beijing, China.,Institute of Sleep and Consciousness Disorders, Beijing Institute of Brain Disorders, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China
| | - Zhaoyang Huang
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China.,Beijing Key Laboratory of Neuromodulation, Beijing, China.,Institute of Sleep and Consciousness Disorders, Beijing Institute of Brain Disorders, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China
| | - Jianghong Liu
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China.,Beijing Key Laboratory of Neuromodulation, Beijing, China.,Institute of Sleep and Consciousness Disorders, Beijing Institute of Brain Disorders, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China
| | - Mingyu Li
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China.,Beijing Key Laboratory of Neuromodulation, Beijing, China.,Institute of Sleep and Consciousness Disorders, Beijing Institute of Brain Disorders, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China
| | - Xiaoling Zhao
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China.,Beijing Key Laboratory of Neuromodulation, Beijing, China.,Institute of Sleep and Consciousness Disorders, Beijing Institute of Brain Disorders, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China
| | - Jing Ye
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China.,Beijing Key Laboratory of Neuromodulation, Beijing, China.,Institute of Sleep and Consciousness Disorders, Beijing Institute of Brain Disorders, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China
| | - Yuping Wang
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China.,Beijing Key Laboratory of Neuromodulation, Beijing, China.,Institute of Sleep and Consciousness Disorders, Beijing Institute of Brain Disorders, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China
| |
Collapse
|
81
|
Jesus-Ribeiro J, Pereira C, Robalo C, Pereira DJ, Duro D, Ramos F, Freire A, Melo JB. DEPDC5 variant in focal cortical dysplasia: a case report and review of the literature. Oxf Med Case Reports 2021; 2021:omab027. [PMID: 34055363 PMCID: PMC8143668 DOI: 10.1093/omcr/omab027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/29/2021] [Accepted: 03/20/2021] [Indexed: 12/03/2022] Open
Abstract
Germline and 2-hit brain somatic variants in DEPDC5 gene, a negative regulator of the mammalian target of rapamycin (mTOR) pathway, are increasingly recognized in patients with focal cortical dysplasia (FCD). Next-generation targeted sequencing identified a heterozygous germline variant in DEPDC5 gene (c.3241A>C, p.Thr1081Pro), classified as of unknown significance, in a patient with clinical features compatible with DEPDC5 phenotype (FCD, focal epilepsy, attention-deficit/hyperactivity disorder and borderline intellectual functioning). This missense variant has previously been reported in two other epileptic patients. Although interpretation of missense variants remains a challenge, DEPDC5 variants in patients with FCD and epilepsy cannot be neglected. Null variants were the most frequently reported in FCD patients, but missense variants have been described as well. The recognition of DEPDC5 phenotype and the appropriate interpretation of the detected variants are essential, since it may have important treatment implications in the near future, namely the use of mTOR inhibitors.
Collapse
Affiliation(s)
- Joana Jesus-Ribeiro
- Epilepsy and Sleep Monitoring Unit, Neurology Department, Coimbra University Hospital Center, Coimbra 3000, Portugal.,iCBR/CIMAGO, Faculty of Medicine, University of Coimbra, Coimbra 3000, Portugal.,Faculty of Medicine, University of Coimbra, Coimbra 3000, Portugal
| | - Cristina Pereira
- Faculty of Medicine, University of Coimbra, Coimbra 3000, Portugal.,Pediatric Neurology of Child Development Center, Pediatric Hospital, Coimbra University Hospital Center, Coimbra 3000, Portugal
| | - Conceição Robalo
- Pediatric Neurology of Child Development Center, Pediatric Hospital, Coimbra University Hospital Center, Coimbra 3000, Portugal
| | - Daniela J Pereira
- Neuroradiology Department, Coimbra University Hospital Center, Coimbra 3000, Portugal
| | - Diana Duro
- Faculty of Medicine, University of Coimbra, Coimbra 3000, Portugal.,Neurology Department, Coimbra University Hospital Center, Coimbra 3000, Portugal
| | - Fabiana Ramos
- Medical Genetics Unit, Pediatric Hospital, Coimbra University Hospital Center, Coimbra 3000, Portugal
| | - António Freire
- Faculty of Medicine, University of Coimbra, Coimbra 3000, Portugal.,Neurology Department, Luz Hospital, Coimbra 3000, Portugal
| | - Joana B Melo
- iCBR/CIMAGO, Faculty of Medicine, University of Coimbra, Coimbra 3000, Portugal.,Laboratory of Cytogenetics and Genomics, Faculty of Medicine, University of Coimbra, Coimbra 3000, Portugal
| |
Collapse
|
82
|
Proietti Onori M, Koene LMC, Schäfer CB, Nellist M, de Brito van Velze M, Gao Z, Elgersma Y, van Woerden GM. RHEB/mTOR hyperactivity causes cortical malformations and epileptic seizures through increased axonal connectivity. PLoS Biol 2021; 19:e3001279. [PMID: 34038402 PMCID: PMC8186814 DOI: 10.1371/journal.pbio.3001279] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 06/08/2021] [Accepted: 05/10/2021] [Indexed: 01/03/2023] Open
Abstract
Hyperactivation of the mammalian target of rapamycin (mTOR) pathway can cause malformation of cortical development (MCD) with associated epilepsy and intellectual disability (ID) through a yet unknown mechanism. Here, we made use of the recently identified dominant-active mutation in Ras Homolog Enriched in Brain 1 (RHEB), RHEBp.P37L, to gain insight in the mechanism underlying the epilepsy caused by hyperactivation of the mTOR pathway. Focal expression of RHEBp.P37L in mouse somatosensory cortex (SScx) results in an MCD-like phenotype, with increased mTOR signaling, ectopic localization of neurons, and reliable generalized seizures. We show that in this model, the mTOR-dependent seizures are caused by enhanced axonal connectivity, causing hyperexcitability of distally connected neurons. Indeed, blocking axonal vesicle release from the RHEBp.P37L neurons alone completely stopped the seizures and normalized the hyperexcitability of the distally connected neurons. These results provide new evidence of the extent of anatomical and physiological abnormalities caused by mTOR hyperactivity, beyond local malformations, which can lead to generalized epilepsy. Hyperactivation of the mTOR pathway can cause cortical malformations and epilepsy. This study reveals that these effects can be uncoupled and that mTOR hyperactivity in a limited set of neurons induces hyperexcitability in non-targeted, healthy neurons, suggesting that it is actually these changes that may underlie mTOR-driven epileptogenesis.
Collapse
Affiliation(s)
- Martina Proietti Onori
- Department of Neuroscience, Erasmus Medical Center, Rotterdam, the Netherlands
- The ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Linda M. C. Koene
- Department of Neuroscience, Erasmus Medical Center, Rotterdam, the Netherlands
- The ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Carmen B. Schäfer
- Department of Neuroscience, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Mark Nellist
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, Zuid Holland, the Netherlands
| | | | - Zhenyu Gao
- Department of Neuroscience, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Ype Elgersma
- Department of Neuroscience, Erasmus Medical Center, Rotterdam, the Netherlands
- The ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus Medical Center, Rotterdam, the Netherlands
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, Zuid Holland, the Netherlands
- * E-mail: (YE); (GMvW)
| | - Geeske M. van Woerden
- Department of Neuroscience, Erasmus Medical Center, Rotterdam, the Netherlands
- The ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus Medical Center, Rotterdam, the Netherlands
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, Zuid Holland, the Netherlands
- * E-mail: (YE); (GMvW)
| |
Collapse
|
83
|
Weston M. Getting Sucker Punched by Depdc5 Really Hurts. Epilepsy Curr 2021; 20:378-380. [PMID: 34025259 PMCID: PMC7818211 DOI: 10.1177/1535759720956992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
[Box: see text]
Collapse
|
84
|
Blümcke I, Coras R, Busch RM, Morita-Sherman M, Lal D, Prayson R, Cendes F, Lopes-Cendes I, Rogerio F, Almeida VS, Rocha CS, Sim NS, Lee JH, Kim SH, Baulac S, Baldassari S, Adle-Biassette H, Walsh CA, Bizzotto S, Doan RN, Morillo KS, Aronica E, Mühlebner A, Becker A, Cienfuegos J, Garbelli R, Giannini C, Honavar M, Jacques TS, Thom M, Mahadevan A, Miyata H, Niehusmann P, Sarnat HB, Söylemezoglu F, Najm I. Toward a better definition of focal cortical dysplasia: An iterative histopathological and genetic agreement trial. Epilepsia 2021; 62:1416-1428. [PMID: 33949696 DOI: 10.1111/epi.16899] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 03/22/2021] [Accepted: 03/23/2021] [Indexed: 12/13/2022]
Abstract
OBJECTIVE Focal cortical dysplasia (FCD) is a major cause of difficult-to-treat epilepsy in children and young adults, and the diagnosis is currently based on microscopic review of surgical brain tissue using the International League Against Epilepsy classification scheme of 2011. We developed an iterative histopathological agreement trial with genetic testing to identify areas of diagnostic challenges in this widely used classification scheme. METHODS Four web-based digital pathology trials were completed by 20 neuropathologists from 15 countries using a consecutive series of 196 surgical tissue blocks obtained from 22 epilepsy patients at a single center. Five independent genetic laboratories performed screening or validation sequencing of FCD-relevant genes in paired brain and blood samples from the same 22 epilepsy patients. RESULTS Histopathology agreement based solely on hematoxylin and eosin stainings was low in Round 1, and gradually increased by adding a panel of immunostainings in Round 2 and the Delphi consensus method in Round 3. Interobserver agreement was good in Round 4 (kappa = .65), when the results of genetic tests were disclosed, namely, MTOR, AKT3, and SLC35A2 brain somatic mutations in five cases and germline mutations in DEPDC5 and NPRL3 in two cases. SIGNIFICANCE The diagnoses of FCD 1 and 3 subtypes remained most challenging and were often difficult to differentiate from a normal homotypic or heterotypic cortical architecture. Immunohistochemistry was helpful, however, to confirm the diagnosis of FCD or no lesion. We observed a genotype-phenotype association for brain somatic mutations in SLC35A2 in two cases with mild malformation of cortical development with oligodendroglial hyperplasia in epilepsy. Our results suggest that the current FCD classification should recognize a panel of immunohistochemical stainings for a better histopathological workup and definition of FCD subtypes. We also propose adding the level of genetic findings to obtain a comprehensive, reliable, and integrative genotype-phenotype diagnosis in the near future.
Collapse
Affiliation(s)
- Ingmar Blümcke
- Department of Neuropathology, University Hospital, Erlangen, Germany.,Epilepsy Center, Cleveland Clinic, Cleveland, OH, USA
| | - Roland Coras
- Department of Neuropathology, University Hospital, Erlangen, Germany
| | - Robyn M Busch
- Epilepsy Center, Cleveland Clinic, Cleveland, OH, USA.,Department of Neurology, Cleveland Clinic, Cleveland, OH, USA.,Genomic Medicine Institute, Cleveland Clinic, Cleveland, OH, USA
| | | | - Dennis Lal
- Epilepsy Center, Cleveland Clinic, Cleveland, OH, USA.,Genomic Medicine Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Richard Prayson
- Department of Anatomic Pathology, Cleveland Clinic, Cleveland, OH, USA
| | - Fernando Cendes
- Department of Neurology, University of Campinas, Sao Paulo, Brazil.,Brazilian Institute of Neuroscience and Neurotechnology, Sao Paulo, Brazil
| | - Iscia Lopes-Cendes
- Brazilian Institute of Neuroscience and Neurotechnology, Sao Paulo, Brazil.,Department of Medical Genetics and Genomic Medicine, University of Campinas, Sao Paulo, Brazil
| | - Fabio Rogerio
- Brazilian Institute of Neuroscience and Neurotechnology, Sao Paulo, Brazil.,Department of Pathology, University of Campinas, Sao Paulo, Brazil
| | - Vanessa S Almeida
- Brazilian Institute of Neuroscience and Neurotechnology, Sao Paulo, Brazil.,Department of Medical Genetics and Genomic Medicine, University of Campinas, Sao Paulo, Brazil
| | - Cristiane S Rocha
- Brazilian Institute of Neuroscience and Neurotechnology, Sao Paulo, Brazil.,Department of Medical Genetics and Genomic Medicine, University of Campinas, Sao Paulo, Brazil
| | - Nam Suk Sim
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Jeong Ho Lee
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, South Korea.,SoVarGen, Inc., Daejeon, Korea
| | - Se Hoon Kim
- Department of Pathology, College of Medicine, Yonsei University, Seoul, South Korea
| | - Stephanie Baulac
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, Paris, France
| | - Sara Baldassari
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, Paris, France
| | - Homa Adle-Biassette
- Pathological Anatomy Service, Public Hospital Network of Paris, Paris, France.,NeuroDiderot, Inserm U1141, University of Paris, Paris, France
| | - Christopher A Walsh
- Division of Genetics and Genomics, Manton Center for Orphan Disease Research, Department of Pediatrics, and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA, USA.,Departments of Pediatrics and Neurology, Harvard Medical School, Boston, MA, USA
| | - Sara Bizzotto
- Division of Genetics and Genomics, Manton Center for Orphan Disease Research, Department of Pediatrics, and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA, USA.,Departments of Pediatrics and Neurology, Harvard Medical School, Boston, MA, USA
| | - Ryan N Doan
- Division of Genetics and Genomics, Manton Center for Orphan Disease Research, Department of Pediatrics, and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA, USA.,Departments of Pediatrics and Neurology, Harvard Medical School, Boston, MA, USA
| | - Katherine S Morillo
- Division of Genetics and Genomics, Manton Center for Orphan Disease Research, Department of Pediatrics, and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA, USA.,Departments of Pediatrics and Neurology, Harvard Medical School, Boston, MA, USA
| | - Eleonora Aronica
- Department of (Neuro)Pathology, Amsterdam UMC, location Academic Medical Center, Amsterdam, the Netherlands.,Epilepsy Institutes of the Netherlands Foundation, Heemstede, the Netherlands
| | - Angelika Mühlebner
- Department of (Neuro)Pathology, Amsterdam UMC, location Academic Medical Center, Amsterdam, the Netherlands.,Department of Pathology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Albert Becker
- Department of Neuropathology, University of Bonn Medical Center, Bonn, Germany
| | - Jesus Cienfuegos
- Department of Anatomic Pathology, International Center for Epilepsy Surgery, Humanitas Medical Group Hospital, Mexico City, Mexico.,Department of Anatomic Pathology, Angels Mexico Hospital, Mexico City, Mexico
| | - Rita Garbelli
- Epilepsy Unit, Carlo Besta Neurological Institute, Scientific Institute for Research and Health Care Foundation, Milan, Italy
| | - Caterina Giannini
- Anatomic Pathology, Mayo Clinic, Rochester, Minnesota, USA.,Department of Biomedical and Neuromotor Science,, Alma Mater Studiorum, University of Bologna, Bologna, Italy
| | - Mrinalini Honavar
- Department of Anatomic Pathology, Pedro Hispano Hospital, Matosinhos, Portugal
| | - Thomas S Jacques
- Developmental Biology and Cancer Research and Teaching Programme, University College London Great Ormond Street Institute of Child Health, London, UK.,Department of Histopathology, Great Ormond Street Hospital for Children, National Health Service Foundation Trust, London, UK
| | - Maria Thom
- Department of Neuropathology, Institute of Neurology, University College London, London, UK
| | - Anita Mahadevan
- Department of Neuropathology, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Hajime Miyata
- Department of Neuropathology, Research Institute for Brain and Blood Vessels, Akita Cerebrospinal and Cardiovascular Center, Akita, Japan
| | - Pitt Niehusmann
- Department of Neuro-/Pathology, Translational Neurodegeneration Research and Neuropathology Lab, University of Oslo and Oslo University Hospital, Oslo, Norway
| | - Harvey B Sarnat
- Department of Paediatrics, University of Calgary Faculty of Medicine, Alberta Children's Hospital Research Institute, Calgary, AB, Canada.,Department of Pathology (Neuropathology),, University of Calgary Faculty of Medicine, Alberta Children's Hospital Research Institute, Calgary, AB, Canada.,Department of Clinical Neurosciences, University of Calgary Faculty of Medicine, Alberta Children's Hospital Research Institute, Calgary, AB, Canada
| | - Figen Söylemezoglu
- Department of Pathology, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - Imad Najm
- Epilepsy Center, Cleveland Clinic, Cleveland, OH, USA.,Department of Neurology, Cleveland Clinic, Cleveland, OH, USA
| |
Collapse
|
85
|
Karalis V, Bateup HS. Current Approaches and Future Directions for the Treatment of mTORopathies. Dev Neurosci 2021; 43:143-158. [PMID: 33910214 PMCID: PMC8440338 DOI: 10.1159/000515672] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 02/13/2021] [Indexed: 11/19/2022] Open
Abstract
The mechanistic target of rapamycin (mTOR) is a kinase at the center of an evolutionarily conserved signaling pathway that orchestrates cell growth and metabolism. mTOR responds to an array of intra- and extracellular stimuli and in turn controls multiple cellular anabolic and catabolic processes. Aberrant mTOR activity is associated with numerous diseases, with particularly profound impact on the nervous system. mTOR is found in two protein complexes, mTOR complex 1 (mTORC1) and 2 (mTORC2), which are governed by different upstream regulators and have distinct cellular actions. Mutations in genes encoding for mTOR regulators result in a collection of neurodevelopmental disorders known as mTORopathies. While these disorders can affect multiple organs, neuropsychiatric conditions such as epilepsy, intellectual disability, and autism spectrum disorder have a major impact on quality of life. The neuropsychiatric aspects of mTORopathies have been particularly challenging to treat in a clinical setting. Current therapeutic approaches center on rapamycin and its analogs, drugs that are administered systemically to inhibit mTOR activity. While these drugs show some clinical efficacy, adverse side effects, incomplete suppression of mTOR targets, and lack of specificity for mTORC1 or mTORC2 may limit their utility. An increased understanding of the neurobiology of mTOR and the underlying molecular, cellular, and circuit mechanisms of mTOR-related disorders will facilitate the development of improved therapeutics. Animal models of mTORopathies have helped unravel the consequences of mTOR pathway mutations in specific brain cell types and developmental stages, revealing an array of disease-related phenotypes. In this review, we discuss current progress and potential future directions for the therapeutic treatment of mTORopathies with a focus on findings from genetic mouse models.
Collapse
Affiliation(s)
- Vasiliki Karalis
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, USA
| | - Helen S Bateup
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, USA
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, California, USA
- Chan Zuckerberg Biohub, San Francisco, California, USA
| |
Collapse
|
86
|
Abstract
INTRODUCTION Focal cortical dysplasias (FCDs) represent the most common etiology in pediatric drug-resistant focal epilepsies undergoing surgical treatment. The localization, extent and histopathological features of FCDs are considerably variable. Somatic mosaic mutations of genes that encode proteins in the PI3K-AKTmTOR pathway, which also includes the tuberous sclerosis associated genes TSC1 and TSC2, have been implicated in FCD type II in a substantial subset of patients. Surgery is the principal therapeutic option for FCD-related epilepsy. Advanced neurophysiological and neuroimaging techniques have improved surgical outcome and reduced the risk of postsurgical deficits. Pharmacological MTOR inhibitors are being tested in clinical trials and might represent an example of personalized treatment of epilepsy based on the known mechanisms of disease, used alone or in combination with surgery. AREAS COVERED This review will critically analyze the advances in the diagnosis and treatment of FCDs, with a special focus on the novel therapeutic options prompted by a better understanding of their pathophysiology. EXPERT OPINION Focal cortical dysplasia is a main cause of drug-resistant epilepsy, especially in children. Novel, personalized approaches are needed to more effectively treat FCD-related epilepsy and its cognitive consequences.
Collapse
Affiliation(s)
- Renzo Guerrini
- Neuroscience Department, Children's Hospital Meyer-University of Florence, Florence, Italy
| | - Carmen Barba
- Neuroscience Department, Children's Hospital Meyer-University of Florence, Florence, Italy
| |
Collapse
|
87
|
Salomone G, Comella M, Portale A, Pecora G, Costanza G, Lo Bianco M, Sciuto S, Praticò ER, Falsaperla R. The Spectrum of DEPDC5-Related Epilepsy. JOURNAL OF PEDIATRIC NEUROLOGY 2021. [DOI: 10.1055/s-0041-1727139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
AbstractDisheveled EGL-10 and pleckstrin domain-containing protein 5 (DEPDC5) is a key member of the GAP activity toward rags complex 1 complex, which inhibits the mammalian target of rapamycin complex 1 (mTORC1) pathway. DEPDC5 loss-of-function mutations lead to an aberrant activation of the mTOR signaling. At neuronal level, the increased mTOR cascade causes the generation of epileptogenic dysplastic neuronal circuits and it is often associated with malformation of cortical development. The DEPDC5 phenotypic spectrum ranges from sporadic early-onset epilepsies with poor neurodevelopmental outcomes to familial focal epilepsies and sudden unexpected death in epilepsy; a high rate of inter- and intrafamilial variability has been reported. To date, clear genotype–phenotype correlations have not been proven. More studies are required to elucidate the significance of likely pathogenic/variants of uncertain significance. The pursuit of a molecular targeted antiepileptic therapy is a future challenge.
Collapse
Affiliation(s)
- Giulia Salomone
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Mattia Comella
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Anna Portale
- Unit of Pediatrics, Avola Hospital, Siracusa, Italy
| | - Giulia Pecora
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Giuseppe Costanza
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Manuela Lo Bianco
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Sarah Sciuto
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | | | - Raffaele Falsaperla
- Unit of Pediatrics and Pediatric Emergency, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
- Units of Neonatal Intensive Care and Neonatology, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
| |
Collapse
|
88
|
Nguyen LH, Bordey A. Convergent and Divergent Mechanisms of Epileptogenesis in mTORopathies. Front Neuroanat 2021; 15:664695. [PMID: 33897381 PMCID: PMC8064518 DOI: 10.3389/fnana.2021.664695] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 03/17/2021] [Indexed: 12/30/2022] Open
Abstract
Hyperactivation of the mechanistic target of rapamycin complex 1 (mTORC1) due to mutations in genes along the PI3K-mTOR pathway and the GATOR1 complex causes a spectrum of neurodevelopmental disorders (termed mTORopathies) associated with malformation of cortical development and intractable epilepsy. Despite these gene variants’ converging impact on mTORC1 activity, emerging findings suggest that these variants contribute to epilepsy through both mTORC1-dependent and -independent mechanisms. Here, we review the literature on in utero electroporation-based animal models of mTORopathies, which recapitulate the brain mosaic pattern of mTORC1 hyperactivity, and compare the effects of distinct PI3K-mTOR pathway and GATOR1 complex gene variants on cortical development and epilepsy. We report the outcomes on cortical pyramidal neuronal placement, morphology, and electrophysiological phenotypes, and discuss some of the converging and diverging mechanisms responsible for these alterations and their contribution to epileptogenesis. We also discuss potential therapeutic strategies for epilepsy, beyond mTORC1 inhibition with rapamycin or everolimus, that could offer personalized medicine based on the gene variant.
Collapse
Affiliation(s)
- Lena H Nguyen
- Department of Neurosurgery, Yale School of Medicine, Yale University, New Haven, CT, United States.,Department of Cellular & Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, United States
| | - Angélique Bordey
- Department of Neurosurgery, Yale School of Medicine, Yale University, New Haven, CT, United States.,Department of Cellular & Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, United States
| |
Collapse
|
89
|
Specchio N, Pepi C, De Palma L, Trivisano M, Vigevano F, Curatolo P. Neuroimaging and genetic characteristics of malformation of cortical development due to mTOR pathway dysregulation: clues for the epileptogenic lesions and indications for epilepsy surgery. Expert Rev Neurother 2021; 21:1333-1345. [PMID: 33754929 DOI: 10.1080/14737175.2021.1906651] [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: 10/21/2022]
Abstract
Introduction: Malformation of cortical development (MCD) is strongly associated with drug-resistant epilepsies for which surgery to remove epileptogenic lesions is common. Two notable technological advances in this field are identification of the underlying genetic cause and techniques in neuroimaging. These now question how presurgical evaluation ought to be approached for 'mTORpathies.'Area covered: From review of published primary and secondary articles, the authors summarize evidence to consider focal cortical dysplasia (FCD), tuber sclerosis complex (TSC), and hemimegalencephaly (HME) collectively as MCD mTORpathies. The authors also consider the unique features of these related conditions with particular focus on the practicalities of using neuroimaging techniques currently available to define surgical targets and predict post-surgical outcome. Ultimately, the authors consider the surgical dilemmas faced for each condition.Expert opinion: Considering FCD, TSC, and HME collectively as mTORpathies has some merit; however, a unified approach to presurgical evaluation would seem unachievable. Nevertheless, the authors believe combining genetic-centered classification and morphologic findings using advanced imaging techniques will eventually form the basis of a paradigm when considering candidacy for early surgery.
Collapse
Affiliation(s)
- Nicola Specchio
- Rare and Complex Epilepsy Unit, Department of Neurosciences, Bambino Gesù Children's Hospital, IRCCS, Member of European Reference Network EpiCARE, Rome, Italy
| | - Chiara Pepi
- Rare and Complex Epilepsy Unit, Department of Neurosciences, Bambino Gesù Children's Hospital, IRCCS, Member of European Reference Network EpiCARE, Rome, Italy
| | - Luca De Palma
- Rare and Complex Epilepsy Unit, Department of Neurosciences, Bambino Gesù Children's Hospital, IRCCS, Member of European Reference Network EpiCARE, Rome, Italy
| | - Marina Trivisano
- Rare and Complex Epilepsy Unit, Department of Neurosciences, Bambino Gesù Children's Hospital, IRCCS, Member of European Reference Network EpiCARE, Rome, Italy
| | - Federico Vigevano
- Department of Neuroscience, Bambino Gesù Children's Hospital, IRCCS, Member of European Reference Network EpiCARE, Rome, Italy
| | - Paolo Curatolo
- Child Neurology and Psychiatry Unit, Systems Medicine Department, Tor Vergata University, Rome, Italy
| |
Collapse
|
90
|
Mary L, Nourisson E, Feger C, Laugel V, Chaigne D, Keren B, Afenjar A, Billette T, Trost D, Cieuta-Walti C, Gerard B, Piton A, Schaefer E. Pathogenic variants in KCNQ2 cause intellectual deficiency without epilepsy: Broadening the phenotypic spectrum of a potassium channelopathy. Am J Med Genet A 2021; 185:1803-1815. [PMID: 33754465 DOI: 10.1002/ajmg.a.62181] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Revised: 01/19/2021] [Accepted: 03/11/2021] [Indexed: 12/22/2022]
Abstract
High-throughput sequencing (HTS) improved the molecular diagnosis in individuals with intellectual deficiency (ID) and helped to broaden the phenotype of previously known disease-causing genes. We report herein four unrelated patients with isolated ID, carriers of a likely pathogenic variant in KCNQ2, a gene usually implicated in benign familial neonatal seizures (BFNS) or early onset epileptic encephalopathy (EOEE). Patients were diagnosed by targeted HTS or exome sequencing. Pathogenicity of the variants was assessed by multiple in silico tools. Patients' ID ranged from mild to severe with predominance of speech disturbance and autistic features. Three of the four variants disrupted the same amino acid. Compiling all the pathogenic variants previously reported, we observed a strong overlap between variants causing EOEE, isolated ID, and BFNS and an important intra-familial phenotypic variability, although missense variants in the voltage-sensing domain and the pore are significantly associated to EOEE (p < 0.01, Fisher test). Thus, pathogenic variants in KCNQ2 can be associated with isolated ID. We did not highlight strong related genotype-phenotype correlations in KCNQ2-related disorders. A second genetic hit, a burden of rare variants, or other extrinsic factors may explain such a phenotypic variability. However, it is of interest to study encephalopathy genes in non-epileptic ID patients.
Collapse
Affiliation(s)
- Laura Mary
- Laboratoire de Diagnostic Génétique, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Elsa Nourisson
- Laboratoire de Diagnostic Génétique, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Claire Feger
- Laboratoire de Diagnostic Génétique, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Vincent Laugel
- Service de Neuropédiatrie, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Denys Chaigne
- Service de Neuropédiatrie, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Boris Keren
- Département de Génétique, Centre de Référence des Déficiences Intellectuelles de Causes Rares, Groupe de Recherche Clinique "Déficiences Intellectuelles et Autisme," Université Pierre et Marie Curie, Hôpital de la Pitié-Salpêtrière, Paris, France.,Institut du Cerveau et de la Moelle Épinière, Sorbonne Universités, Université Pierre et Marie Curie (Université Paris 06), UMRS 1127, INSERM U 1127, CNRS UMR 7225, Paris, France
| | - Alexandra Afenjar
- Centre de Référence Déficiences Intellectuelles de Causes Rares, Département de Génétique et Embryologie Médicale, Hôpital Trousseau, Sorbonne Universités, Paris, France
| | - Thierry Billette
- Assistance Publique-Hôpitaux de Paris, Service de Neuropédiatrie, Hôpital Armand Trousseau, Paris, France
| | | | | | - Bénédicte Gerard
- Laboratoire de Diagnostic Génétique, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Amélie Piton
- Laboratoire de Diagnostic Génétique, Hôpitaux Universitaires de Strasbourg, Strasbourg, France.,Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), CNRS UMR-7104, Inserm U964, Université de Strasbourg, Strasbourg, France
| | - Elise Schaefer
- Service de Génétique Médicale, Hôpitaux Universitaires de Strasbourg, Institut de Génétique Médicale d'Alsace, Strasbourg, France
| |
Collapse
|
91
|
Kao HY, Hu S, Mihaylova T, Ziobro J, Ahn E, Fine C, Brang D, Watson BO, Wang Y. Defining the latent period of epileptogenesis and epileptogenic zone in a focal cortical dysplasia type II (FCDII) rat model. Epilepsia 2021; 62:1268-1279. [PMID: 33735460 PMCID: PMC8211029 DOI: 10.1111/epi.16868] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 02/21/2021] [Accepted: 02/22/2021] [Indexed: 12/14/2022]
Abstract
Objectives Focal cortical dysplasia type II (FCDII) is one of the most common underlying pathologies in patients with drug‐resistant epilepsy. However, mechanistic understanding of FCDII fails to keep pace with genetic discoveries, primarily due to the significant challenge in developing a clinically relevant animal model. Conceptually and clinically important questions, such as the unknown latent period of epileptogenesis and the controversial epileptogenic zone, remain unknown in all experimental FCDII animal models, making it even more challenging to investigate the underlying epileptogenic mechanisms. Methods In this study, we used continuous video‐electroencephalography (EEG) monitoring to detect the earliest interictal and ictal events in a clustered regularly interspaced short palindromic repeats (CRISPR)‐in utero electroporation (IUE) FCDII rat model that shares genetic, pathological, and electroclinical signatures with those observed in humans. We then took advantage of in vivo local field potential (LFP) recordings to localize the epileptogenic zone in these animals. Results To the best of our knowledge, we showed for the first time that epileptiform discharges emerged during the third postnatal week, and that the first seizure occurred as early as during the fourth postnatal week. We also showed that both interictal and ictal discharges are localized within the dysplastic cortex, concordant with human clinical data. Significance Together, our work identified the temporal and spatial frame of epileptogenesis in a highly clinically relevant FCDII animal model, paving the way for mechanistic studies at molecular, cellular, and circuitry levels.
Collapse
Affiliation(s)
- Hsin-Yi Kao
- Department of Neurology, University of Michigan, Ann Arbor, USA
| | - Shuntong Hu
- Department of Neurology, University of Michigan, Ann Arbor, USA.,Department of Neurology, the Third Xiangya Hospital, Central South University, Changsha, China
| | | | - Julie Ziobro
- Department of Pediatrics, University of Michigan, Ann Arbor, USA
| | - EunSeon Ahn
- Department of Psychology, University of Michigan, Ann Arbor, USA
| | - Carli Fine
- Department of Psychology, University of Michigan, Ann Arbor, USA
| | - David Brang
- Department of Psychology, University of Michigan, Ann Arbor, USA
| | - Brendon O Watson
- Department of Psychiatry, University of Michigan, Ann Arbor, USA.,Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, USA
| | - Yu Wang
- Department of Neurology, University of Michigan, Ann Arbor, USA
| |
Collapse
|
92
|
Yang X, Zhang X, Ma Y, Wang Z, Huang K, Liu G, Shen K, Zhu G, Wang T, Lv S, Zhang C, Yang H, Liu S. Abnormal Rat Cortical Development Induced by Ventricular Injection of rHMGB1 Mimics the Pathophysiology of Human Cortical Dysplasia. Front Cell Dev Biol 2021; 9:634405. [PMID: 33748118 PMCID: PMC7969805 DOI: 10.3389/fcell.2021.634405] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 02/12/2021] [Indexed: 11/17/2022] Open
Abstract
Cortical dysplasia (CD) is a common cause of drug-resistant epilepsy. Increasing studies have implicated innate immunity in CD with epilepsy. However, it is unclear whether innate immune factors induce epileptogenic CD. Here, we injected recombinant human high mobility group box 1 (rHMGB1) into embryonic rat ventricles to determine whether rHMGB1 can induce epileptogenic CD with pathophysiological characteristics similar to those of human CD. Compared with controls and 0.1 μg rHMGB1-treated rats, the cortical organization was severely disrupted in the 0.2 μg rHMGB1-treated rats, and microgyria and heterotopia also emerged; additionally, disoriented and deformed neurons were observed in the cortical lesions and heterotopias. Subcortical heterotopia appeared in the white matter and the gray–white junction of the 0.2 μg rHMGB1-treated rats. Moreover, there was decreased number of neurons in layer V–VI and an increased number of astrocytes in layer I and V of the cortical lesions. And the HMGB1 antagonist dexmedetomidine alleviated the changes induced by rHMGB1. Further, we found that TLR4 and NF-κB were increased after rHMGB1 administration. In addition, the excitatory receptors, N-methyl-D-aspartate receptor 1 (NR1), 2A (NR2A), and 2B (NR2B) immunoreactivity were increased, and immunoreactivity of excitatory amino acid transporter 1 (EAAT1) and 2 (EAAT2) were reduced in 0.2 μg rHMGB1-treated rats compared with controls. While there were no differences in the glutamic acid decarboxylase 65/67 (GAD65/67) immunoreactivity between the two groups. These results indicate that the excitation of cortical lesions was significantly increased. Furthermore, electroencephalogram (EEG) showed a shorter latency of seizure onset and a higher incidence of status epilepticus in the 0.2 μg rHMGB1-treated rats; the frequency and amplitude of EEG were higher in the treated rats than controls. Intriguingly, spontaneous electrographic seizure discharges were detected in the 0.2 μg rHMGB1-treated rats after 5 months of age, and spike-wave discharges of approximately 8 Hz were the most significantly increased synchronous propagated waves throughout the general brain cortex. Taken together, these findings indicate that rHMGB1 exposure during pregnancy could contribute to the development of epileptogenic CD, which mimicked some pathophysiological characteristics of human CD.
Collapse
Affiliation(s)
- Xiaolin Yang
- National Comprehensive Epilepsy Center, Department of Neurosurgery, Second Affiliated Hospital, Army Medical University, Chongqing, China
| | - Xiaoqing Zhang
- National Comprehensive Epilepsy Center, Department of Neurosurgery, Second Affiliated Hospital, Army Medical University, Chongqing, China
| | - Yuanshi Ma
- National Comprehensive Epilepsy Center, Department of Neurosurgery, Second Affiliated Hospital, Army Medical University, Chongqing, China.,Department of Neurosurgery, First People's Hospital, Zhaotong, China
| | - Zhongke Wang
- National Comprehensive Epilepsy Center, Department of Neurosurgery, Second Affiliated Hospital, Army Medical University, Chongqing, China
| | - Kaixuan Huang
- National Comprehensive Epilepsy Center, Department of Neurosurgery, Second Affiliated Hospital, Army Medical University, Chongqing, China
| | - Guolong Liu
- National Comprehensive Epilepsy Center, Department of Neurosurgery, Second Affiliated Hospital, Army Medical University, Chongqing, China
| | - Kaifeng Shen
- National Comprehensive Epilepsy Center, Department of Neurosurgery, Second Affiliated Hospital, Army Medical University, Chongqing, China
| | - Gang Zhu
- National Comprehensive Epilepsy Center, Department of Neurosurgery, Second Affiliated Hospital, Army Medical University, Chongqing, China
| | - Tingting Wang
- National Comprehensive Epilepsy Center, Department of Neurosurgery, Second Affiliated Hospital, Army Medical University, Chongqing, China
| | - Shengqing Lv
- National Comprehensive Epilepsy Center, Department of Neurosurgery, Second Affiliated Hospital, Army Medical University, Chongqing, China
| | - Chunqing Zhang
- National Comprehensive Epilepsy Center, Department of Neurosurgery, Second Affiliated Hospital, Army Medical University, Chongqing, China
| | - Hui Yang
- National Comprehensive Epilepsy Center, Department of Neurosurgery, Second Affiliated Hospital, Army Medical University, Chongqing, China
| | - Shiyong Liu
- National Comprehensive Epilepsy Center, Department of Neurosurgery, Second Affiliated Hospital, Army Medical University, Chongqing, China
| |
Collapse
|
93
|
Severino M, Geraldo AF, Utz N, Tortora D, Pogledic I, Klonowski W, Triulzi F, Arrigoni F, Mankad K, Leventer RJ, Mancini GMS, Barkovich JA, Lequin MH, Rossi A. Definitions and classification of malformations of cortical development: practical guidelines. Brain 2021; 143:2874-2894. [PMID: 32779696 PMCID: PMC7586092 DOI: 10.1093/brain/awaa174] [Citation(s) in RCA: 120] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 03/14/2020] [Accepted: 03/30/2020] [Indexed: 12/31/2022] Open
Abstract
Malformations of cortical development are a group of rare disorders commonly manifesting with developmental delay, cerebral palsy or seizures. The neurological outcome is extremely variable depending on the type, extent and severity of the malformation and the involved genetic pathways of brain development. Neuroimaging plays an essential role in the diagnosis of these malformations, but several issues regarding malformations of cortical development definitions and classification remain unclear. The purpose of this consensus statement is to provide standardized malformations of cortical development terminology and classification for neuroradiological pattern interpretation. A committee of international experts in paediatric neuroradiology prepared systematic literature reviews and formulated neuroimaging recommendations in collaboration with geneticists, paediatric neurologists and pathologists during consensus meetings in the context of the European Network Neuro-MIG initiative on Brain Malformations (https://www.neuro-mig.org/). Malformations of cortical development neuroimaging features and practical recommendations are provided to aid both expert and non-expert radiologists and neurologists who may encounter patients with malformations of cortical development in their practice, with the aim of improving malformations of cortical development diagnosis and imaging interpretation worldwide.
Collapse
Affiliation(s)
| | - Ana Filipa Geraldo
- Neuroradiology Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy.,Neuroradiology Unit, Imaging Department, Centro Hospitalar Vila Nova de Gaia/Espinho (CHVNG/E), Vila Nova de Gaia, Portugal
| | - Norbert Utz
- Department of Pediatric Radiology, HELIOS Klinikum Krefeld, Germany
| | - Domenico Tortora
- Neuroradiology Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Ivana Pogledic
- Division of Neuroradiology and Musculoskeletal Radiology, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Wlodzimierz Klonowski
- Nalecz Institute of Biocybernetics and Biomedical Engineering Polish Academy of Sciences, Poland
| | - Fabio Triulzi
- Neuroradiology Unit, Fondazione IRCCS Cà Granda, Ospedale Maggiore Policlinico, Department of Pathophysiology and Transplantation, Università degli Studi Milano, Italy
| | - Filippo Arrigoni
- Department of Neuroimaging Lab, Scientific Institute, IRCCS E. Medea, Bosisio Parini, Italy
| | - Kshitij Mankad
- Department of Radiology, Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond Street, London, UK
| | - Richard J Leventer
- Department of Neurology Royal Children's Hospital, Murdoch Children's Research Institute and University of Melbourne Department of Pediatrics, Melbourne, Australia
| | - Grazia M S Mancini
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - James A Barkovich
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA.,Department of Neurology, University of California, San Francisco, CA, USA
| | - Maarten H Lequin
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Andrea Rossi
- Neuroradiology Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| |
Collapse
|
94
|
Jesus-Ribeiro J, Pires LM, Melo JD, Ribeiro IP, Rebelo O, Sales F, Freire A, Melo JB. Genomic and Epigenetic Advances in Focal Cortical Dysplasia Types I and II: A Scoping Review. Front Neurosci 2021; 14:580357. [PMID: 33551717 PMCID: PMC7862327 DOI: 10.3389/fnins.2020.580357] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Accepted: 12/14/2020] [Indexed: 12/19/2022] Open
Abstract
Introduction: Focal cortical dysplasias (FCDs) are a group of malformations of cortical development that constitute a common cause of drug-resistant epilepsy, often subjected to neurosurgery, with a suboptimal long-term outcome. The past few years have witnessed a dramatic leap in our understanding of the molecular basis of FCD. This study aimed to provide an updated review on the genomic and epigenetic advances underlying FCD etiology, to understand a genotype-phenotype correlation and identify priorities to lead future translational research. Methods: A scoping review of the literature was conducted, according to previously described methods. A comprehensive search strategy was applied in PubMed, Embase, and Web of Science from inception to 07 May 2020. References were screened based on title and abstract, and posteriorly full-text articles were assessed for inclusion according to eligibility criteria. Studies with novel gene variants or epigenetic regulatory mechanisms in patients that underwent epilepsy surgery, with histopathological diagnosis of FCD type I or II according to Palmini's or the ILAE classification system, were included. Data were extracted and summarized for an overview of evidence. Results: Of 1,156 candidate papers, 39 met the study criteria and were included in this review. The advent of next-generation sequencing enabled the detection in resected FCD tissue of low-level brain somatic mutations that occurred during embryonic corticogenesis. The mammalian target of rapamycin (mTOR) signaling pathway, involved in neuronal growth and migration, is the key player in the pathogenesis of FCD II. Somatic gain-of-function variants in MTOR and its activators as well as germline, somatic, and second-hit mosaic loss-of-function variants in its related repressors have been reported. However, the genetic background of FCD type I remains elusive, with a pleomorphic repertoire of genes affected. DNA methylation and microRNAs were the two epigenetic mechanisms that proved to have a functional role in FCD and may represent molecular biomarkers. Conclusion: Further research into the possible pathogenic causes of both FCD subtypes is required, incorporating single-cell DNA/RNA sequencing as well as methylome and proteomic analysis. The collected data call for an integrated clinicopathologic and molecular genetic diagnosis in current practice not only to improve diagnostic accuracy but also to guide the development of future targeted treatments.
Collapse
Affiliation(s)
- Joana Jesus-Ribeiro
- Epilepsy and Sleep Monitoring Unit, Neurology Department, Coimbra University Hospital Center, Coimbra, Portugal.,iCBR/CIMAGO, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Luís Miguel Pires
- iCBR/CIMAGO, Faculty of Medicine, University of Coimbra, Coimbra, Portugal.,Laboratory of Cytogenetics and Genomics, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | | | - Ilda Patrícia Ribeiro
- iCBR/CIMAGO, Faculty of Medicine, University of Coimbra, Coimbra, Portugal.,Laboratory of Cytogenetics and Genomics, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Olinda Rebelo
- Neuropathology Laboratory, Neurology Department, Coimbra University Hospital Center, Coimbra, Portugal
| | - Francisco Sales
- Epilepsy and Sleep Monitoring Unit, Neurology Department, Coimbra University Hospital Center, Coimbra, Portugal
| | - António Freire
- Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Joana Barbosa Melo
- iCBR/CIMAGO, Faculty of Medicine, University of Coimbra, Coimbra, Portugal.,Laboratory of Cytogenetics and Genomics, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| |
Collapse
|
95
|
Abstract
PURPOSE OF REVIEW To review the evolution of the concept of epileptic encephalopathy during the course of past years and analyze how the current definition might impact on both clinical practice and research. RECENT FINDINGS Developmental delay in children with epilepsy could be the expression of the cause, consequence of intense epileptiform activity (seizures and EEG abnormalities), or because of the combination of both factors. Therefore, the current International League Against Epilepsy classification identified three electroclinical entities that are those of developmental encephalopathy, epileptic encephalopathy, and developmental and epileptic encephalopathy (DEE). Many biological pathways could be involved in the pathogenesis of DEEs. DNA repair, transcriptional regulation, axon myelination, metabolite and ion transport, and peroxisomal function could all be involved in DEE. Also, epilepsy and epileptiform discharges might impact on cognition via several mechanisms, although they are not fully understood. SUMMARY The correct and early identification of cause in DEE might increase the chances of a targeted treatment regimen. Interfering with neurobiological processes of the disease will be the most successful way in order to improve both the cognitive disturbances and epilepsy that are the key features of DEE.
Collapse
|
96
|
The Importance of Magnetic Resonance in Detection of Cortical Dysplasia. CURRENT HEALTH SCIENCES JOURNAL 2021; 47:585-589. [PMID: 35444831 PMCID: PMC8987480 DOI: 10.12865/chsj.47.04.16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 11/20/2021] [Indexed: 11/18/2022]
Abstract
Focal cortical dysplasia is a malformation of cortical development in which there are abnormalities with cortical lamination, neuronal maturation, and neuronal differentiation. It is the most common cause of medically refractory epilepsy in the pediatric population and the second/third most common etiology of medically intractable seizures in adults. Herein, we present the case of 23-years-old female patient, presenting with loss of consciousness, and convulsions. A MRI revealed a 5mm cortical thickening on either side of the posterior aspect of the right superior temporal gyrus without transmantle extension towards ventricle. This abnormal area is measured about 24x16mm and there was no evidence for mesial temporal sclerosis. Both hippocampi are normal is size, morphology and signal. These features are consistent with cortical dysplasia type 1. This case report emphasizes the importance of MRI in the detection of FCD. MRI can show no abnormalities in type 1 FCD, but when the changes are apparent, they are on the temporal lobe, and seizures presents most commonly in adults.
Collapse
|
97
|
Benova B, Sanders MWCB, Uhrova-Meszarosova A, Belohlavkova A, Hermanovska B, Novak V, Stanek D, Vlckova M, Zamecnik J, Aronica E, Braun KPJ, Koeleman BPC, Jansen FE, Krsek P. GATOR1-related focal cortical dysplasia in epilepsy surgery patients and their families: A possible gradient in severity? Eur J Paediatr Neurol 2021; 30:88-96. [PMID: 33461085 DOI: 10.1016/j.ejpn.2020.12.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 10/16/2020] [Accepted: 12/04/2020] [Indexed: 12/23/2022]
Abstract
BACKGROUND Variants of GATOR1-genes represent a recognised cause of focal cortical dysplasia (FCD), the most common structural aetiology in paediatric drug-resistant focal epilepsy. Reports on familial cases of GATOR1-associated FCD are limited, especially with respect to epilepsy surgery outcomes. METHODS We present phenotypical manifestations of four unrelated patients with drug-resistant focal epilepsy, FCD and a first-degree relative with epilepsy. All patients underwent targeted gene panel sequencing as a part of the presurgical work up. Literature search was performed to compare our findings to previously published cases. RESULTS The children (probands) had a more severe phenotype than their parents, including drug-resistant epilepsy and developmental delay, and they failed to achieve seizure freedom post-surgically. All patients had histopathologically confirmed FCD (types IIa, IIb, Ia). In Patient 1 and her affected father, we detected a known pathogenic NPRL2 variant. In patients 2 and 3 and their affected parents, we found novel likely pathogenic germline DEPDC5 variants. In family 4, we detected a novel variant in NPRL3. We identified 15 additional cases who underwent epilepsy surgery for GATOR1-associated FCD, with a positive family history of epilepsy in the literature; in 8/13 tested, the variant was inherited from an asymptomatic parent. CONCLUSION The presented cases displayed a severity gradient in phenotype with children more severely affected than the parents. Although patients with GATOR1-associated FCD are considered good surgical candidates, post-surgical seizure outcome was poor in our familial cases, suggesting that accurate identification of the epileptogenic zone may be more challenging in this subgroup of patients.
Collapse
Affiliation(s)
- Barbora Benova
- Department of Paediatric Neurology, Motol Epilepsy Center, 2nd Faculty of Medicine, Charles University and Motol University Hospital, V Uvalu 84, 15006, Prague, Czech Republic; Neurogenetics Laboratory of the Department of Paediatric Neurology, 2nd Faculty of Medicine, Charles University and Motol University Hospital, V Uvalu 84, Prague, 15006, Czech Republic.
| | - Maurits W C B Sanders
- Department of Child Neurology, Brain Center University Medical Center Utrecht, the Netherlands.
| | - Anna Uhrova-Meszarosova
- Department of Paediatric Neurology, Motol Epilepsy Center, 2nd Faculty of Medicine, Charles University and Motol University Hospital, V Uvalu 84, 15006, Prague, Czech Republic; Neurogenetics Laboratory of the Department of Paediatric Neurology, 2nd Faculty of Medicine, Charles University and Motol University Hospital, V Uvalu 84, Prague, 15006, Czech Republic.
| | - Anezka Belohlavkova
- Department of Paediatric Neurology, Motol Epilepsy Center, 2nd Faculty of Medicine, Charles University and Motol University Hospital, V Uvalu 84, 15006, Prague, Czech Republic.
| | - Barbora Hermanovska
- Department of Paediatric Neurology, Motol Epilepsy Center, 2nd Faculty of Medicine, Charles University and Motol University Hospital, V Uvalu 84, 15006, Prague, Czech Republic.
| | - Vilem Novak
- Department of Paediatric Neurology, Ostrava Faculty Hospital, 17. Listopadu 1790, 708 00, Ostrava-Poruba, Czech Republic.
| | - David Stanek
- Neurogenetics Laboratory of the Department of Paediatric Neurology, 2nd Faculty of Medicine, Charles University and Motol University Hospital, V Uvalu 84, Prague, 15006, Czech Republic.
| | - Marketa Vlckova
- Department of Biology and Medical Genetics, 2nd Faculty of Medicine, Charles University and Motol University Hospital, V Uvalu 84, 15006, Prague, Czech Republic.
| | - Josef Zamecnik
- Department of Pathology and Molecular Medicine, 2nd Faculty of Medicine, Charles University and Motol University Hospital, V Uvalu 84, 15006, Prague, Czech Republic.
| | - Eleonora Aronica
- Amsterdam UMC, University of Amsterdam, Department of (Neuro)Pathology, Amsterdam, Meibergdreef 9, 1105, AZ Amsterdam, the Netherlands; Stichting Epilepsie Instellingen Nederland (SEIN), Achterweg 2, 2103, SW, Heemstede, the Netherlands.
| | - Kees P J Braun
- Department of Child Neurology, Brain Center University Medical Center Utrecht, the Netherlands.
| | - Bobby P C Koeleman
- Department of Genetics, University Medical Center Utrecht, Utrecht, the Netherlands.
| | - Floor E Jansen
- Department of Child Neurology, Brain Center University Medical Center Utrecht, the Netherlands.
| | - Pavel Krsek
- Department of Paediatric Neurology, Motol Epilepsy Center, 2nd Faculty of Medicine, Charles University and Motol University Hospital, V Uvalu 84, 15006, Prague, Czech Republic.
| |
Collapse
|
98
|
Wang Y, Chen Y, Wang SM, Liu X, Gu YN, Feng Z. Prenatal diagnosis of Duchenne muscular dystrophy revealed a novel mosaic mutation in Dystrophin gene: a case report. BMC MEDICAL GENETICS 2020; 21:222. [PMID: 33176713 PMCID: PMC7661169 DOI: 10.1186/s12881-020-01157-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 10/25/2020] [Indexed: 11/10/2022]
Abstract
BACKGROUND Duchenne muscular dystrophies (DMDs) are X-linked recessive neuromuscular disorders with malfunction or absence of the Dystrophin protein. Precise genetic diagnosis is critical for proper planning of patient care and treatment. In this study, we described a Chinese family with mosaic DMD mutations and discussed the best method for prenatal diagnosis and genetic counseling of X-linked familial disorders. METHODS We investigated all variants of the whole dystrophin gene using multiple DNA samples isolated from the affected family and identified two variants of the DMD gene in a sick boy and two female carriers by targeted next generation sequencing (TNGS), Sanger sequencing, and haplotype analysis. RESULTS We identified the hemizygous mutation c.6794delG (p.G2265Efs*6) of DMD in the sick boy, which was inherited from his mother. Unexpectedly, a novel heterozygous mutation c.6796delA (p.I2266Ffs*5) of the same gene, which was considered to be a de novo variant, was detected from his younger sister instead of his mother by Sanger sequencing. However, further NGS analysis of the mother and her amniotic fluid samples revealed that the mother carried a low-level mosaic c.6796delA mutation. CONCLUSIONS We reported two different mutations of the DMD gene in two siblings, including the novel mutation c.6796delA (p.I2266Ffs*5) inherited from the asymptomatic mosaic-carrier mother. This finding has enriched the knowledge of the pathogenesis of DMD. If no mutation is detected in obligate carriers, the administration of intricate STR/NGS/Sanger analysis will provide new ideas on the prenatal diagnosis of DMD.
Collapse
Affiliation(s)
- Yan Wang
- Department of Clinical Genetics, BaYi Children's Hospital, Seventh Medical Center of Chinese PLA General Hospital, Beijing, 100700, China. .,National Engineering Laboratory for Birth defects prevention and control of key technology, Beijing, 100700, China. .,Beijing Key Laboratory of Pediatric Organ Failure, Beijing, 100700, China. .,Clinical Biobank Center, Chinese PLA General Hospital, Beijing, 100853, China.
| | - Yuhan Chen
- Department of Clinical Genetics, BaYi Children's Hospital, Seventh Medical Center of Chinese PLA General Hospital, Beijing, 100700, China.,National Engineering Laboratory for Birth defects prevention and control of key technology, Beijing, 100700, China.,Beijing Key Laboratory of Pediatric Organ Failure, Beijing, 100700, China.,Department of Pediatrics, Chinese PLA General Hospital, Beijing, 100700, China
| | - San Mei Wang
- Department of Clinical Genetics, BaYi Children's Hospital, Seventh Medical Center of Chinese PLA General Hospital, Beijing, 100700, China.,National Engineering Laboratory for Birth defects prevention and control of key technology, Beijing, 100700, China.,Beijing Key Laboratory of Pediatric Organ Failure, Beijing, 100700, China.,Department of Pediatrics, Chinese PLA General Hospital, Beijing, 100700, China
| | - Xin Liu
- Department of Clinical Genetics, BaYi Children's Hospital, Seventh Medical Center of Chinese PLA General Hospital, Beijing, 100700, China.,National Engineering Laboratory for Birth defects prevention and control of key technology, Beijing, 100700, China.,Beijing Key Laboratory of Pediatric Organ Failure, Beijing, 100700, China.,Department of Pediatrics, Chinese PLA General Hospital, Beijing, 100700, China
| | - Ya Nan Gu
- Department of Clinical Genetics, BaYi Children's Hospital, Seventh Medical Center of Chinese PLA General Hospital, Beijing, 100700, China.,National Engineering Laboratory for Birth defects prevention and control of key technology, Beijing, 100700, China.,Beijing Key Laboratory of Pediatric Organ Failure, Beijing, 100700, China.,Department of Pediatrics, Chinese PLA General Hospital, Beijing, 100700, China
| | - Zhichun Feng
- Department of Clinical Genetics, BaYi Children's Hospital, Seventh Medical Center of Chinese PLA General Hospital, Beijing, 100700, China. .,National Engineering Laboratory for Birth defects prevention and control of key technology, Beijing, 100700, China. .,Beijing Key Laboratory of Pediatric Organ Failure, Beijing, 100700, China. .,Department of Pediatrics, Chinese PLA General Hospital, Beijing, 100700, China.
| |
Collapse
|
99
|
Castello MA, Gleeson JG. Insight into developmental mechanisms of global and focal migration disorders of cortical development. Curr Opin Neurobiol 2020; 66:77-84. [PMID: 33099181 DOI: 10.1016/j.conb.2020.10.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 10/02/2020] [Accepted: 10/05/2020] [Indexed: 12/20/2022]
Abstract
Cortical development involves neurogenesis followed by migration, maturation, and myelination of immature neurons. Disruptions in these processes can cause malformations of cortical development (MCD). Radial glia (RG) are the stem cells of the brain, both generating neurons and providing the scaffold upon which immature neurons radially migrate. Germline mutations in genes required for cell migration, or cell-cell contact, often lead to global MCDs. Somatic mutations in RG in genes involved in homeostatic function, like mTOR signaling, often lead to focal MCDs. Two different mutations occurring in the same patient can combine in ways we are just beginning to understand. Our growing knowledge about MCD suggests mTOR inhibitors may have expanded utility in treatment-resistant epilepsy, while imaging techniques can better delineate the type and extent of these lesions.
Collapse
Affiliation(s)
- Michael A Castello
- Department of Neurosciences, Division of Child Neurology, University of California San Diego, San Diego, CA, USA
| | - Joseph G Gleeson
- Department of Neurosciences, Rady Children's Institute for Genomic Medicine, University of California San Diego, San Diego, CA, USA.
| |
Collapse
|
100
|
International consensus recommendations on the diagnostic work-up for malformations of cortical development. Nat Rev Neurol 2020; 16:618-635. [PMID: 32895508 PMCID: PMC7790753 DOI: 10.1038/s41582-020-0395-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/20/2020] [Indexed: 12/22/2022]
Abstract
Malformations of cortical development (MCDs) are neurodevelopmental disorders that result from abnormal development of the cerebral cortex in utero. MCDs place a substantial burden on affected individuals, their families and societies worldwide, as these individuals can experience lifelong drug-resistant epilepsy, cerebral palsy, feeding difficulties, intellectual disability and other neurological and behavioural anomalies. The diagnostic pathway for MCDs is complex owing to wide variations in presentation and aetiology, thereby hampering timely and adequate management. In this article, the international MCD network Neuro-MIG provides consensus recommendations to aid both expert and non-expert clinicians in the diagnostic work-up of MCDs with the aim of improving patient management worldwide. We reviewed the literature on clinical presentation, aetiology and diagnostic approaches for the main MCD subtypes and collected data on current practices and recommendations from clinicians and diagnostic laboratories within Neuro-MIG. We reached consensus by 42 professionals from 20 countries, using expert discussions and a Delphi consensus process. We present a diagnostic workflow that can be applied to any individual with MCD and a comprehensive list of MCD-related genes with their associated phenotypes. The workflow is designed to maximize the diagnostic yield and increase the number of patients receiving personalized care and counselling on prognosis and recurrence risk.
Collapse
|