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Garcia-Uzquiano R, Barcia G, Losito E, Chemaly N, Kaminska A, Desguerre I, Blauwblomme T, Boddaert N, Nabbout R. Genetic testing, another important tool in presurgical evaluation of focal epilepsies in childhood. Epilepsia Open 2024. [PMID: 38829689 DOI: 10.1002/epi4.12964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 05/03/2024] [Indexed: 06/05/2024] Open
Abstract
Epilepsy surgery may be a curative therapy for patients with drug-resistant epilepsies when focal lesions or foci are identified. Genetic testing is not yet routinely included in many presurgical evaluation programs although recent evidence support that finding a germline genetic mutation could help to better delineate the patient candidacy to surgery and provide valuable information on the expected surgery outcome. In this study, we report nine patients presenting drug-resistant focal epilepsy enrolled in presurgical evaluation. We show how the identification of genetic pathogenic variant in epilepsy known genes led to the interruption of the presurgical work-up and ruled out surgery in 7 of them. We observed that the co-existence of some recurrent clinical characteristics as early seizures' onset, frequent precipitating factors including fever, and developmental delay or intellectual disability may be useful markers for germline genetic pathogenic variants. In this group, genetic assessment should be mandatory during presurgical work up, mainly in patients with negative magnetic resonance imaging (MRI) or doubtful structural lesions. The integration of next generation targeted sequencing into the presurgical evaluation can improve the selection of candidates for resective surgery and fosters a personalized medicine approach with a better outcome. PLAINE LANGUAGE ABSTRACT: Genetic testing is not yet systematically included in the pre-surgical assessment of patients with drug-resistant focal epilepsies. In this study, through the description of nine patients, we underline how the integration of genomics into the presurgical work up can help in evaluating the patient candidacy to surgery and provide valuable information on expected surgery outcome.
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Affiliation(s)
- Rocio Garcia-Uzquiano
- Department of Pediatric Neurology, Reference Centre for Rare Epilepsies, Paris, France
| | - Giulia Barcia
- Department of Genetics, Necker Enfants Malades Hospital, AP-HP, Paris, France
- Imagine Institute, Laboratory of Translational Research for Neurological Disorders, INSERM UMR 1163, Paris, France
- University of Paris Cité, Paris, France
| | - Emma Losito
- Department of Pediatric Neurology, Reference Centre for Rare Epilepsies, Paris, France
- Unit of Pediatric Neurophysiology, Necker Enfants Malades Hospital, AP-HP, Paris, France
| | - Nicole Chemaly
- Department of Pediatric Neurology, Reference Centre for Rare Epilepsies, Paris, France
- Imagine Institute, Laboratory of Translational Research for Neurological Disorders, INSERM UMR 1163, Paris, France
- University of Paris Cité, Paris, France
| | - Anna Kaminska
- Department of Pediatric Neurology, Reference Centre for Rare Epilepsies, Paris, France
- Unit of Pediatric Neurophysiology, Necker Enfants Malades Hospital, AP-HP, Paris, France
| | - Isabelle Desguerre
- Department of Pediatric Neurology, Reference Centre for Rare Epilepsies, Paris, France
- University of Paris Cité, Paris, France
| | - Thomas Blauwblomme
- University of Paris Cité, Paris, France
- Department of Pediatric Neurosurgery, Necker Enfants Malades Hospital, AP-HP, Paris, France
| | - Nathalie Boddaert
- University of Paris Cité, Paris, France
- Department of Pediatric Radiology, Necker Enfants Malades Hospital, AP-HP, Paris, France
| | - Rima Nabbout
- Department of Pediatric Neurology, Reference Centre for Rare Epilepsies, Paris, France
- Imagine Institute, Laboratory of Translational Research for Neurological Disorders, INSERM UMR 1163, Paris, France
- University of Paris Cité, Paris, France
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2
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Shore AN, Li K, Safari M, Qunies AM, Spitznagel BD, Weaver CD, Emmitte KA, Frankel WN, Weston MC. Heterozygous expression of a Kcnt1 gain-of-function variant has differential effects on SST- and PV-expressing cortical GABAergic neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.10.11.561953. [PMID: 37873369 PMCID: PMC10592778 DOI: 10.1101/2023.10.11.561953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
More than twenty recurrent missense gain-of-function (GOF) mutations have been identified in the sodium-activated potassium (K Na ) channel gene KCNT1 in patients with severe developmental and epileptic encephalopathies (DEEs), most of which are resistant to current therapies. Defining the neuron types most vulnerable to KCNT1 GOF will advance our understanding of disease mechanisms and provide refined targets for precision therapy efforts. Here, we assessed the effects of heterozygous expression of a Kcnt1 GOF variant (Y777H) on K Na currents and neuronal physiology among cortical glutamatergic and GABAergic neurons in mice, including those expressing vasoactive intestinal polypeptide (VIP), somatostatin (SST), and parvalbumin (PV), to identify and model the pathogenic mechanisms of autosomal dominant KCNT1 GOF variants in DEEs. Although the Kcnt1 -Y777H variant had no effects on glutamatergic or VIP neuron function, it increased subthreshold K Na currents in both SST and PV neurons but with opposite effects on neuronal output; SST neurons became hypoexcitable with a higher rheobase current and lower action potential (AP) firing frequency, whereas PV neurons became hyperexcitable with a lower rheobase current and higher AP firing frequency. Further neurophysiological and computational modeling experiments showed that the differential effects of the Y777H variant on SST and PV neurons are not likely due to inherent differences in these neuron types, but to an increased persistent sodium current in PV, but not SST, neurons. The Y777H variant also increased excitatory input onto, and chemical and electrical synaptic connectivity between, SST neurons. Together, these data suggest differential pathogenic mechanisms, both direct and compensatory, contribute to disease phenotypes, and provide a salient example of how a pathogenic ion channel variant can cause opposite functional effects in closely related neuron subtypes due to interactions with other ionic conductances.
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3
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Iraci N, Carotenuto L, Ciaglia T, Belperio G, Di Matteo F, Mosca I, Carleo G, Giovanna Basilicata M, Ambrosino P, Turcio R, Puzo D, Pepe G, Gomez-Monterrey I, Soldovieri MV, Di Sarno V, Campiglia P, Miceli F, Bertamino A, Ostacolo C, Taglialatela M. In Silico Assisted Identification, Synthesis, and In Vitro Pharmacological Characterization of Potent and Selective Blockers of the Epilepsy-Associated KCNT1 Channel. J Med Chem 2024. [PMID: 38782404 DOI: 10.1021/acs.jmedchem.4c00268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2024]
Abstract
Gain-of-function (GoF) variants in KCNT1 channels cause severe, drug-resistant forms of epilepsy. Quinidine is a known KCNT1 blocker, but its clinical use is limited due to severe drawbacks. To identify novel KCNT1 blockers, a homology model of human KCNT1 was built and used to screen an in-house library of compounds. Among the 20 molecules selected, five (CPK4, 13, 16, 18, and 20) showed strong KCNT1-blocking ability in an in vitro fluorescence-based assay. Patch-clamp experiments confirmed a higher KCNT1-blocking potency of these compounds when compared to quinidine, and their selectivity for KCNT1 over hERG and Kv7.2 channels. Among identified molecules, CPK20 displayed the highest metabolic stability; this compound also blocked KCNT2 currents, although with a lower potency, and counteracted GoF effects prompted by 2 recurrent epilepsy-causing KCNT1 variants (G288S and A934T). The present results provide solid rational basis for future design of novel compounds to counteract KCNT1-related neurological disorders.
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Affiliation(s)
- Nunzio Iraci
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences (CHIBIOFARAM), University of Messina, Viale F. Stagno d'Alcontres 31, 98166 Messina, Italy
| | - Lidia Carotenuto
- Department of Neuroscience, Reproductive Sciences and Dentistry, University Federico II of Naples, Via S. Pansini, 5, 80131 Naples, Italy
| | - Tania Ciaglia
- Department of Pharmacy, University of Salerno, Via G. Paolo II 132, 84084 Fisciano, SA, Italy
| | - Giorgio Belperio
- Department of Science and Technology, University of Sannio, Via F. De Sanctis, 82100 Benevento, Italy
| | - Francesca Di Matteo
- Department of Pharmacy, University of Salerno, Via G. Paolo II 132, 84084 Fisciano, SA, Italy
| | - Ilaria Mosca
- Department of Medicine and Health Science Vincenzo Tiberio, University of Molise, Via C. Gazzani, 86100 Campobasso, Italy
| | - Giusy Carleo
- Department of Neuroscience, Reproductive Sciences and Dentistry, University Federico II of Naples, Via S. Pansini, 5, 80131 Naples, Italy
| | - Manuela Giovanna Basilicata
- Department of Advanced Medical and Surgical Sciences, University of Campania "Luigi Vanvitelli", P.zza L. Miraglia 2, 80138 Naples, Italy
| | - Paolo Ambrosino
- Department of Science and Technology, University of Sannio, Via F. De Sanctis, 82100 Benevento, Italy
| | - Rita Turcio
- Department of Pharmacy, University of Salerno, Via G. Paolo II 132, 84084 Fisciano, SA, Italy
| | - Deborah Puzo
- Department of Medicine and Health Science Vincenzo Tiberio, University of Molise, Via C. Gazzani, 86100 Campobasso, Italy
| | - Giacomo Pepe
- Department of Pharmacy, University of Salerno, Via G. Paolo II 132, 84084 Fisciano, SA, Italy
| | - Isabel Gomez-Monterrey
- Department of Pharmacy, University Federico II of Naples, Via D. Montesano 49, 80131 Naples, Italy
| | - Maria Virginia Soldovieri
- Department of Medicine and Health Science Vincenzo Tiberio, University of Molise, Via C. Gazzani, 86100 Campobasso, Italy
| | - Veronica Di Sarno
- Department of Pharmacy, University of Salerno, Via G. Paolo II 132, 84084 Fisciano, SA, Italy
| | - Pietro Campiglia
- Department of Pharmacy, University of Salerno, Via G. Paolo II 132, 84084 Fisciano, SA, Italy
| | - Francesco Miceli
- Department of Neuroscience, Reproductive Sciences and Dentistry, University Federico II of Naples, Via S. Pansini, 5, 80131 Naples, Italy
| | - Alessia Bertamino
- Department of Pharmacy, University of Salerno, Via G. Paolo II 132, 84084 Fisciano, SA, Italy
| | - Carmine Ostacolo
- Department of Pharmacy, University of Salerno, Via G. Paolo II 132, 84084 Fisciano, SA, Italy
| | - Maurizio Taglialatela
- Department of Neuroscience, Reproductive Sciences and Dentistry, University Federico II of Naples, Via S. Pansini, 5, 80131 Naples, Italy
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4
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Cole BA, Kalli AC, Pilati N, Muench SP, Lippiat JD. A molecular switch in RCK2 triggers sodium-dependent activation of K Na1.1 (KCNT1) potassium channels. Biophys J 2024:S0006-3495(24)00251-0. [PMID: 38605520 DOI: 10.1016/j.bpj.2024.04.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 01/12/2024] [Accepted: 04/08/2024] [Indexed: 04/13/2024] Open
Abstract
The Na+-activated K+ channel KNa1.1, encoded by the KCNT1 gene, is an important regulator of neuronal excitability. How intracellular Na+ ions bind and increase channel activity is not well understood. Analysis of KNa1.1 channel structures indicate that there is a large twisting of the βN-αQ loop in the intracellular RCK2 domain between the inactive and Na+-activated conformations, with a lysine (K885, human subunit numbering) close enough to potentially form a salt bridge with an aspartate (D839) in βL in the Na+-activated state. Concurrently, an aspartate (D884) adjacent in the same loop adopts a position within a pocket formed by the βO strand. In carrying out mutagenesis and electrophysiology with human KNa1.1, we found that alanine substitution of selected residues in these regions resulted in almost negligible currents in the presence of up to 40 mM intracellular Na+. The exception was D884A, which resulted in constitutively active channels in both the presence and absence of intracellular Na+. Further mutagenesis of this site revealed an amino acid size-dependent effect. Substitutions at this site by an amino acid smaller than aspartate (D884V) also yielded constitutively active KNa1.1, and D884I had Na+ dependence similar to wild-type KNa1.1, while increasing the side-chain size larger than aspartate (D884E or D884F) yielded channels that could not be activated by up to 40 mM intracellular Na+. We conclude that Na+ binding results in a conformational change that accommodates D884 in the βO pocket, which triggers further conformational changes in the RCK domains and channel activation.
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Affiliation(s)
- Bethan A Cole
- School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
| | - Antreas C Kalli
- Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, United Kingdom; Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds, United Kingdom
| | | | - Stephen P Muench
- School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom; Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds, United Kingdom
| | - Jonathan D Lippiat
- School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom.
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5
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Mosca I, Freri E, Ambrosino P, Belperio G, Granata T, Canafoglia L, Ragona F, Solazzi R, Filareto I, Castellotti B, Messina G, Gellera C, DiFrancesco JC, Soldovieri MV, Taglialatela M. Case report: Marked electroclinical improvement by fluoxetine treatment in a patient with KCNT1-related drug-resistant focal epilepsy. Front Cell Neurosci 2024; 18:1367838. [PMID: 38644974 PMCID: PMC11027738 DOI: 10.3389/fncel.2024.1367838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 03/11/2024] [Indexed: 04/23/2024] Open
Abstract
Variants in KCNT1 are associated with a wide spectrum of epileptic phenotypes, including epilepsy of infancy with migrating focal seizures (EIMFS), non-EIMFS developmental and epileptic encephalopathies, autosomal dominant or sporadic sleep-related hypermotor epilepsy, and focal epilepsy. Here, we describe a girl affected by drug-resistant focal seizures, developmental delay and behavior disorders, caused by a novel, de novo heterozygous missense KCNT1 variant (c.2809A > G, p.S937G). Functional characterization in transiently transfected Chinese Hamster Ovary (CHO) cells revealed a strong gain-of-function effect determined by the KCNT1 p.S937G variant compared to wild-type, consisting in an increased maximal current density and a hyperpolarizing shift in current activation threshold. Exposure to the antidepressant drug fluoxetine inhibited currents expressed by both wild-type and mutant KCNT1 channels. Treatment of the proband with fluoxetine led to a prolonged electroclinical amelioration, with disappearance of seizures and better EEG background organization, together with an improvement in behavior and mood. Altogether, these results suggest that, based on the proband's genetic and functional characteristics, the antidepressant drug fluoxetine may be repurposed for the treatment of focal epilepsy caused by gain-of-function variants in KCNT1. Further studies are needed to verify whether this approach could be also applied to other phenotypes of the KCNT1-related epilepsies spectrum.
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Affiliation(s)
- Ilaria Mosca
- Department of Medicine and Health Sciences “Vincenzo Tiberio”, University of Molise, Campobasso, Italy
| | - Elena Freri
- Department of Pediatric Neuroscience, Fondazione IRCCS Istituto Neurologico “Carlo Besta”, Milan, Italy
| | - Paolo Ambrosino
- Department of Science and Technology, University of Sannio, Benevento, Italy
| | - Giorgio Belperio
- Department of Science and Technology, University of Sannio, Benevento, Italy
| | - Tiziana Granata
- Department of Pediatric Neuroscience, Fondazione IRCCS Istituto Neurologico “Carlo Besta”, Milan, Italy
| | - Laura Canafoglia
- Department of Diagnostic and Technology, Fondazione IRCCS Istituto Neurologico “Carlo Besta”, Milan, Italy
| | - Francesca Ragona
- Department of Pediatric Neuroscience, Fondazione IRCCS Istituto Neurologico “Carlo Besta”, Milan, Italy
| | - Roberta Solazzi
- Department of Pediatric Neuroscience, Fondazione IRCCS Istituto Neurologico “Carlo Besta”, Milan, Italy
| | - Ilaria Filareto
- Department of Pediatric Neuroscience, Fondazione IRCCS Istituto Neurologico “Carlo Besta”, Milan, Italy
| | - Barbara Castellotti
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico C. Besta, Milan, Italy
| | - Giuliana Messina
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico C. Besta, Milan, Italy
| | - Cinzia Gellera
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico C. Besta, Milan, Italy
| | | | - Maria Virginia Soldovieri
- Department of Medicine and Health Sciences “Vincenzo Tiberio”, University of Molise, Campobasso, Italy
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6
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Dhanapalaratnam R, Issar T, Poynten AM, Milner KL, Kwai NCG, Krishnan AV. Progression of axonal excitability abnormalities with increasing clinical severity of diabetic peripheral neuropathy. Clin Neurophysiol 2024; 160:12-18. [PMID: 38367309 DOI: 10.1016/j.clinph.2024.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 01/18/2024] [Accepted: 02/05/2024] [Indexed: 02/19/2024]
Abstract
OBJECTIVE Diabetic peripheral neuropathy (DPN) is a frequent complication for persons with type 2 diabetes. Previous studies have failed to demonstrate any significant impact of treatment for DPN. The present study assessed the role of axonal ion channel dysfunction in DPN and explored the hypothesis that there may be a progressive change in ion channel abnormalities that varied with disease stage. METHODS Neurophysiological studies were conducted using axonal excitability techniques, a clinical method of assessing ion channel dysfunction. Studies were conducted in 178 persons with type 2 diabetes, with participants allocated into four groups according to clinical severity of neuropathy, assessed using the Total Neuropathy Grade. RESULTS Analysis of excitability data demonstrated a progressive and stepwise reduction in two parameters that are related to the activity of Kv1.1 channels, namely superexcitability and depolarizing threshold electrotonus at 10-20 ms (p < 0.001), and mathematical modelling of axonal excitability findings supported progressive upregulation of Kv1.1 conductances with increasing greater disease severity. CONCLUSION The findings are consistent with a progressive upregulation of juxtaparanodal Kv1.1 conductances with increasing clinical severity of diabetic peripheral neuropathy. SIGNIFICANCE From a translational perspective, the study suggests that blockade of Kv1.1 channels using 4-aminopyridine derivatives such as fampridine may be a potential treatment for DPN.
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Affiliation(s)
- Roshan Dhanapalaratnam
- School of Clinical Medicine, UNSW Sydney, NSW 2031, Australia; Department of Neurology, Prince of Wales Hospital, Sydney, NSW 2031, Australia
| | - Tushar Issar
- School of Clinical Medicine, UNSW Sydney, NSW 2031, Australia
| | - Ann M Poynten
- School of Clinical Medicine, UNSW Sydney, NSW 2031, Australia; Department of Endocrinology, Prince of Wales Hospital, Sydney, NSW 2031, Australia
| | - Kerry-Lee Milner
- School of Clinical Medicine, UNSW Sydney, NSW 2031, Australia; Department of Endocrinology, Prince of Wales Hospital, Sydney, NSW 2031, Australia
| | - Natalie C G Kwai
- School of Medical, Indigenous and Health Sciences, University of Wollongong, Australia
| | - Arun V Krishnan
- School of Clinical Medicine, UNSW Sydney, NSW 2031, Australia; Department of Neurology, Prince of Wales Hospital, Sydney, NSW 2031, Australia.
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7
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Chengyan L, Chupeng X, You W, Yinhui C, Binglong H, Dang A, Ling L, Chuan T. Identification of genetic causes in children with unexplained epilepsy based on trio-whole exome sequencing. Clin Genet 2024. [PMID: 38468460 DOI: 10.1111/cge.14519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 02/25/2024] [Accepted: 02/26/2024] [Indexed: 03/13/2024]
Abstract
Genotype and clinical phenotype analyses of 128 children were performed based on whole exome sequencing (WES), providing a reference for the provision of genetic counseling and the precise diagnosis and treatment of epilepsy. A total of 128 children with unexplained epilepsy were included in this study, and all their clinical data were analyzed. The children's treatments, epilepsy control, and neurodevelopmental levels were regularly followed up every 3 months. The genetic diagnostic yield of the 128 children with epilepsy is 50.8%, with an SNV diagnostic yield of 39.8% and a CNV diagnostic yield of 12.5%. Among the 128 children with epilepsy, 57.0% had onset of epilepsy in infancy, 25.8% have more than two clinical seizure forms, 62.5% require two or more anti-epileptic drug treatments, and 72.7% of the children have varying degrees of psychomotor development retardation. There are significant differences between ages of onset, neurodevelopmental levels and the presence of drug resistance in the genetic diagnostic yield (all p < 0.05). The 52 pathogenic/likely pathogenic SNVs involve 31 genes, with genes encoding ion channels having the largest number of mutations (30.8%). There were 16 cases of pathogenic/possibly pathogenic CNVs, among which the main proportions of CNVs were located in chromosome 15 and chromosome 16. Trio-WES is an essential tool for the genetic diagnosis of unexplained epilepsy, with a genetic diagnostic yield of up to 50.8%. Early genetic testing can provide an initiate appropriate therapies and accurate molecular diagnosis.
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Affiliation(s)
- Li Chengyan
- Department of Pediatrics, Affiliated Hospital of Guangdong Medical University, Zhanjiang, People's Republic of China
| | - Xue Chupeng
- Department of Pediatrics, Affiliated Hospital of Guangdong Medical University, Zhanjiang, People's Republic of China
- Department of Pediatrics, Shantou Central Hospital, Shantou, People's Republic of China
| | - Wang You
- Department of Pediatrics, Affiliated Hospital of Guangdong Medical University, Zhanjiang, People's Republic of China
| | - Chen Yinhui
- Department of Pediatrics, Affiliated Hospital of Guangdong Medical University, Zhanjiang, People's Republic of China
| | - Huang Binglong
- Department of Pediatrics, Affiliated Hospital of Guangdong Medical University, Zhanjiang, People's Republic of China
| | - Ao Dang
- Department of Pediatrics, Affiliated Hospital of Guangdong Medical University, Zhanjiang, People's Republic of China
| | - Liu Ling
- Department of Pediatrics, Affiliated Hospital of Guangdong Medical University, Zhanjiang, People's Republic of China
| | - Tian Chuan
- Department of Pediatrics, Affiliated Hospital of Guangdong Medical University, Zhanjiang, People's Republic of China
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8
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Hussain R, Lim CX, Shaukat Z, Islam A, Caseley EA, Lippiat JD, Rychkov GY, Ricos MG, Dibbens LM. Drosophila expressing mutant human KCNT1 transgenes make an effective tool for targeted drug screening in a whole animal model of KCNT1-epilepsy. Sci Rep 2024; 14:3357. [PMID: 38336906 PMCID: PMC10858247 DOI: 10.1038/s41598-024-53588-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 02/01/2024] [Indexed: 02/12/2024] Open
Abstract
Mutations in the KCNT1 potassium channel cause severe forms of epilepsy which are poorly controlled with current treatments. In vitro studies have shown that KCNT1-epilepsy mutations are gain of function, significantly increasing K+ current amplitudes. To investigate if Drosophila can be used to model human KCNT1 epilepsy, we generated Drosophila melanogaster lines carrying human KCNT1 with the patient mutation G288S, R398Q or R928C. Expression of each mutant channel in GABAergic neurons gave a seizure phenotype which responded either positively or negatively to 5 frontline epilepsy drugs most commonly administered to patients with KCNT1-epilepsy, often with little or no improvement of seizures. Cannabidiol showed the greatest reduction of the seizure phenotype while some drugs increased the seizure phenotype. Our study shows that Drosophila has the potential to model human KCNT1- epilepsy and can be used as a tool to assess new treatments for KCNT1- epilepsy.
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Affiliation(s)
- Rashid Hussain
- Epilepsy Research Group, Clinical and Health Sciences, Australian Centre for Precision Health, University of South Australia, Adelaide, SA, 5000, Australia
| | - Chiao Xin Lim
- Epilepsy Research Group, Clinical and Health Sciences, Australian Centre for Precision Health, University of South Australia, Adelaide, SA, 5000, Australia
- Pharmacy, School of Health and Biomedical Sciences, RMIT University, Bundoora, VIC, 3083, Australia
| | - Zeeshan Shaukat
- Epilepsy Research Group, Clinical and Health Sciences, Australian Centre for Precision Health, University of South Australia, Adelaide, SA, 5000, Australia
| | - Anowarul Islam
- Epilepsy Research Group, Clinical and Health Sciences, Australian Centre for Precision Health, University of South Australia, Adelaide, SA, 5000, Australia
- College of Medicine and Public Health, Flinders University, Bedford Park, SA, 5042, Australia
| | - Emily A Caseley
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Jonathan D Lippiat
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Grigori Y Rychkov
- Epilepsy Research Group, Clinical and Health Sciences, Australian Centre for Precision Health, University of South Australia, Adelaide, SA, 5000, Australia
- School of Biomedicine, University of Adelaide, Adelaide, SA, 5005, Australia
- South Australian Health and Medical Research Institute, Adelaide, SA, 5005, Australia
| | - Michael G Ricos
- Epilepsy Research Group, Clinical and Health Sciences, Australian Centre for Precision Health, University of South Australia, Adelaide, SA, 5000, Australia
| | - Leanne M Dibbens
- Epilepsy Research Group, Clinical and Health Sciences, Australian Centre for Precision Health, University of South Australia, Adelaide, SA, 5000, Australia.
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9
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Yuan T, Wang Y, Jin Y, Yang H, Xu S, Zhang H, Chen Q, Li N, Ma X, Song H, Peng C, Geng Z, Dong J, Duan G, Sun Q, Yang Y, Yang F, Huang Z. Coupling of Slack and Na V1.6 sensitizes Slack to quinidine blockade and guides anti-seizure strategy development. eLife 2024; 12:RP87559. [PMID: 38289338 PMCID: PMC10942592 DOI: 10.7554/elife.87559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2024] Open
Abstract
Quinidine has been used as an anticonvulsant to treat patients with KCNT1-related epilepsy by targeting gain-of-function KCNT1 pathogenic mutant variants. However, the detailed mechanism underlying quinidine's blockade against KCNT1 (Slack) remains elusive. Here, we report a functional and physical coupling of the voltage-gated sodium channel NaV1.6 and Slack. NaV1.6 binds to and highly sensitizes Slack to quinidine blockade. Homozygous knockout of NaV1.6 reduces the sensitivity of native sodium-activated potassium currents to quinidine blockade. NaV1.6-mediated sensitization requires the involvement of NaV1.6's N- and C-termini binding to Slack's C-terminus and is enhanced by transient sodium influx through NaV1.6. Moreover, disrupting the Slack-NaV1.6 interaction by viral expression of Slack's C-terminus can protect against SlackG269S-induced seizures in mice. These insights about a Slack-NaV1.6 complex challenge the traditional view of 'Slack as an isolated target' for anti-epileptic drug discovery efforts and can guide the development of innovative therapeutic strategies for KCNT1-related epilepsy.
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Affiliation(s)
- Tian Yuan
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science CenterBeijingChina
| | - Yifan Wang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science CenterBeijingChina
| | - Yuchen Jin
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science CenterBeijingChina
| | - Hui Yang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science CenterBeijingChina
| | - Shuai Xu
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science CenterBeijingChina
| | - Heng Zhang
- NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang UniversityZhejiangChina
| | - Qian Chen
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science CenterBeijingChina
| | - Na Li
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science CenterBeijingChina
| | - Xinyue Ma
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science CenterBeijingChina
| | - Huifang Song
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science CenterBeijingChina
| | - Chao Peng
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science CenterBeijingChina
| | - Ze Geng
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science CenterBeijingChina
| | - Jie Dong
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science CenterBeijingChina
| | - Guifang Duan
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science CenterBeijingChina
| | - Qi Sun
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science CenterBeijingChina
| | - Yang Yang
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue UniversityWest LafayetteUnited States
| | - Fan Yang
- NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang UniversityZhejiangChina
- Department of Biophysics, Kidney Disease Center of the First Affiliated Hospital, Zhejiang University School of Medicine, HangzhouZhejiangChina
| | - Zhuo Huang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science CenterBeijingChina
- IDG/McGovern Institute for Brain Research, Peking UniversityBeijingChina
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10
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Skrabak D, Bischof H, Pham T, Ruth P, Ehinger R, Matt L, Lukowski R. Slack K + channels limit kainic acid-induced seizure severity in mice by modulating neuronal excitability and firing. Commun Biol 2023; 6:1029. [PMID: 37821582 PMCID: PMC10567740 DOI: 10.1038/s42003-023-05387-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 09/25/2023] [Indexed: 10/13/2023] Open
Abstract
Mutations of the Na+-activated K+ channel Slack (KCNT1) are associated with terrible epilepsy syndromes that already begin in infancy. Here we report increased severity of acute kainic acid-induced seizures in adult and juvenile Slack knockout mice (Slack-/-) in vivo. Fittingly, we find exacerbation of cell death following kainic acid exposure in organotypic hippocampal slices as well as dissociated hippocampal cultures from Slack-/- in vitro. Furthermore, in cultured Slack-/- neurons, kainic acid-triggered Ca2+ influx and K+ efflux as well as depolarization-induced tetrodotoxin-sensitive inward currents are higher compared to the respective controls. This apparent changes in ion homeostasis could possibly explain altered action potential kinetics of Slack-/- neurons: steeper rise slope, decreased threshold, and duration of afterhyperpolarization, which ultimately lead to higher action potential frequencies during kainic acid application or injection of depolarizing currents. Based on our data, we propose Slack as crucial gatekeeper of neuronal excitability to acutely limit seizure severity.
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Affiliation(s)
- David Skrabak
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Helmut Bischof
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Thomas Pham
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Peter Ruth
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Rebekka Ehinger
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Lucas Matt
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Robert Lukowski
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany.
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11
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Hinckley CA, Zhu Z, Chu JH, Gubbels C, Danker T, Cherry JJ, Whelan CD, Engle SJ, Nguyen V. Functional evaluation of epilepsy-associated KCNT1 variants in multiple cellular systems reveals a predominant gain of function impact on channel properties. Epilepsia 2023; 64:2126-2136. [PMID: 37177976 DOI: 10.1111/epi.17648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 05/11/2023] [Accepted: 05/11/2023] [Indexed: 05/15/2023]
Abstract
OBJECTIVE Gain of function variants in the sodium-activated potassium channel KCNT1 have been associated with pediatric epilepsy disorders. Here, we systematically examine a spectrum of KCNT1 variants and establish their impact on channel function in multiple cellular systems. METHODS KCNT1 variants identified from published reports and genetic screening of pediatric epilepsy patients were expressed in Xenopus oocytes and HEK cell lines. Variant impact on current magnitude, current-voltage relationships, and sodium ion modulation were examined. RESULTS We determined basic properties of KCNT1 in Xenopus oocyte and HEK systems, including the role of extra- and intracellular sodium in regulating KCNT1 activity. The most common six KCNT1 variants demonstrated strong gain of function (GOF) effects on one or more channel properties. Analysis of 36 total variants identified phenotypic heterogeneity but a strong tendency for pathogenic variants to exert GOF effects on channel properties. By controlling intracellular sodium, we demonstrate that multiple pathogenic KCNT1 variants modulate channel voltage dependence by altering the sensitivity to sodium ions. SIGNIFICANCE This study represents the largest systematic functional examination of KCNT1 variants to date. We both confirm previously reported GOF channel phenotypes and expand the number of variants with in vitro GOF effects. Our data provide further evidence that novel KCNT1 variants identified in epilepsy patients lead to disease through generalizable GOF mechanisms including increases in current magnitude and/or current-voltage relationships.
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Affiliation(s)
| | | | | | | | - Timm Danker
- NMI Technologietransfer GmbH, Reutlingen, Germany
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12
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Wojcik MH, Poduri AH, Holm IA, MacRae CA, Goldstein RD. The fundamental need for unifying phenotypes in sudden unexpected pediatric deaths. Front Med (Lausanne) 2023; 10:1166188. [PMID: 37332751 PMCID: PMC10273404 DOI: 10.3389/fmed.2023.1166188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 05/03/2023] [Indexed: 06/20/2023] Open
Abstract
A definitive, authoritative approach to evaluate the causes of unexpected, and ultimately unexplained, pediatric deaths remains elusive, relegating final conclusions to diagnoses of exclusion in the vast majority of cases. Research into unexplained pediatric deaths has focused primarily on sudden infant deaths (under 1 year of age) and led to the identification of several potential, albeit incompletely understood, contributory factors: nonspecific pathology findings, associations with sleep position and environment that may not be uniformly relevant, and the elucidation of a role for serotonin that is practically difficult to estimate in any individual case. Any assessment of progress in this field must also acknowledge the failure of current approaches to substantially decrease mortality rates in decades. Furthermore, potential commonalities with pediatric deaths across a broader age spectrum have not been widely considered. Recent epilepsy-related observations and genetic findings, identified post-mortem in both infants and children who died suddenly and unexpectedly, suggest a role for more intense and specific phenotyping efforts as well as an expanded role for genetic and genomic evaluation. We therefore present a new approach to reframe the phenotype in sudden unexplained deaths in the pediatric age range, collapsing many distinctions based on arbitrary factors (such as age) that have previously guided research in this area, and discuss its implications for the future of postmortem investigation.
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Affiliation(s)
- Monica H. Wojcik
- Robert’s Program for Sudden Unexpected Death in Pediatrics, Boston Children’s Hospital, Boston, MA, United States
- Division of Newborn Medicine, Department of Pediatrics, Boston Children’s Hospital, Boston, MA, United States
- Division of Genetics and Genomics, Department of Pediatrics, Boston Children’s Hospital, Boston, MA, United States
- Harvard Medical School, Boston, MA, United States
| | - Annapurna H. Poduri
- Robert’s Program for Sudden Unexpected Death in Pediatrics, Boston Children’s Hospital, Boston, MA, United States
- Harvard Medical School, Boston, MA, United States
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, United States
- Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, MA, United States
| | - Ingrid A. Holm
- Robert’s Program for Sudden Unexpected Death in Pediatrics, Boston Children’s Hospital, Boston, MA, United States
- Division of Genetics and Genomics, Department of Pediatrics, Boston Children’s Hospital, Boston, MA, United States
- Harvard Medical School, Boston, MA, United States
| | - Calum A. MacRae
- Harvard Medical School, Boston, MA, United States
- Department of Medicine, Brigham and Women's Hospital, Boston, MA, United States
| | - Richard D. Goldstein
- Robert’s Program for Sudden Unexpected Death in Pediatrics, Boston Children’s Hospital, Boston, MA, United States
- Harvard Medical School, Boston, MA, United States
- Division of General Pediatrics, Department of Pediatrics, Boston Children's Hospital, Boston, MA, United States
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13
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Donnan AM, Schneider AL, Russ-Hall S, Churilov L, Scheffer IE. Rates of Status Epilepticus and Sudden Unexplained Death in Epilepsy in People With Genetic Developmental and Epileptic Encephalopathies. Neurology 2023; 100:e1712-e1722. [PMID: 36750385 PMCID: PMC10115508 DOI: 10.1212/wnl.0000000000207080] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Accepted: 01/05/2023] [Indexed: 02/09/2023] Open
Abstract
BACKGROUND AND OBJECTIVES The genetic developmental and epileptic encephalopathies (DEEs) comprise a large group of severe epilepsy syndromes, with a wide phenotypic spectrum. Currently, the rates of convulsive status epilepticus (CSE), nonconvulsive status epilepticus (NCSE), and sudden unexplained death in epilepsy (SUDEP) in these diseases are not well understood. We aimed to describe the proportions of patients with frequently observed genetic DEEs who developed CSE, NCSE, mortality, and SUDEP. Understanding the risks of these serious presentations in each genetic DEE will enable earlier diagnosis and appropriate management. METHODS In this retrospective analysis of patients with a genetic DEE, we estimated the proportions with CSE, NCSE, and SUDEP and the overall and SUDEP-specific mortality rates for each genetic diagnosis. We included patients with a pathogenic variant in the genes SCN1A, SCN2A, SCN8A, SYNGAP1, NEXMIF, CHD2, PCDH19, STXBP1, GRIN2A, KCNT1, and KCNQ2 and with Angelman syndrome (AS). RESULTS The cohort comprised 510 individuals with a genetic DEE, in whom we observed CSE in 47% and NCSE in 19%. The highest proportion of CSE occurred in patients with SCN1A-associated DEEs, including 181/203 (89%; 95% CI 84-93) patients with Dravet syndrome and 8/15 (53%; 95% CI 27-79) non-Dravet SCN1A-DEEs. CSE was also notable in patients with pathogenic variants in KCNT1 (6/10; 60%; 95% CI 26-88) and SCN2A (8/15; 53%; 95% CI 27-79). NCSE was common in patients with non-Dravet SCN1A-DEEs (8/15; 53%; 95% CI 27-79) and was notable in patients with CHD2-DEEs (6/14; 43%; 95% CI 18-71) and AS (6/19; 32%; 95% CI 13-57). There were 42/510 (8%) deaths among the cohort, producing a mortality rate of 6.1 per 1,000 person-years (95% CI 4.4-8.3). Cases of SUDEP accounted for 19/42 (48%) deaths. Four genes were associated with SUDEP: SCN1A, SCN2A, SCN8A, and STXBP1. The estimated SUDEP rate was 2.8 per 1,000 person-years (95% CI 1.6-4.3). DISCUSSION We showed that proportions of patients with CSE, NCSE, and SUDEP differ for commonly encountered genetic DEEs. The estimates for each genetic DEE studied will inform early diagnosis and management of status epilepticus and SUDEP and inform disease-specific counseling for patients and families in this high-risk group of conditions.
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Affiliation(s)
- Alice M Donnan
- From the Epilepsy Research Centre (A.M.D., A.L.S., S.R.-H., I.E.S.), Department of Medicine, The University of Melbourne, Austin Health; Melbourne Medical School (L.C.), Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville; The Florey Institute of Neurosciences and Mental Health (L.C., I.E.S.), Melbourne; and Department of Paediatrics (I.E.S.), The University of Melbourne, Royal Children's Hospital, and Murdoch Children's Research Institute, Victoria, Australia
| | - Amy L Schneider
- From the Epilepsy Research Centre (A.M.D., A.L.S., S.R.-H., I.E.S.), Department of Medicine, The University of Melbourne, Austin Health; Melbourne Medical School (L.C.), Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville; The Florey Institute of Neurosciences and Mental Health (L.C., I.E.S.), Melbourne; and Department of Paediatrics (I.E.S.), The University of Melbourne, Royal Children's Hospital, and Murdoch Children's Research Institute, Victoria, Australia
| | - Sophie Russ-Hall
- From the Epilepsy Research Centre (A.M.D., A.L.S., S.R.-H., I.E.S.), Department of Medicine, The University of Melbourne, Austin Health; Melbourne Medical School (L.C.), Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville; The Florey Institute of Neurosciences and Mental Health (L.C., I.E.S.), Melbourne; and Department of Paediatrics (I.E.S.), The University of Melbourne, Royal Children's Hospital, and Murdoch Children's Research Institute, Victoria, Australia
| | - Leonid Churilov
- From the Epilepsy Research Centre (A.M.D., A.L.S., S.R.-H., I.E.S.), Department of Medicine, The University of Melbourne, Austin Health; Melbourne Medical School (L.C.), Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville; The Florey Institute of Neurosciences and Mental Health (L.C., I.E.S.), Melbourne; and Department of Paediatrics (I.E.S.), The University of Melbourne, Royal Children's Hospital, and Murdoch Children's Research Institute, Victoria, Australia
| | - Ingrid E Scheffer
- From the Epilepsy Research Centre (A.M.D., A.L.S., S.R.-H., I.E.S.), Department of Medicine, The University of Melbourne, Austin Health; Melbourne Medical School (L.C.), Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville; The Florey Institute of Neurosciences and Mental Health (L.C., I.E.S.), Melbourne; and Department of Paediatrics (I.E.S.), The University of Melbourne, Royal Children's Hospital, and Murdoch Children's Research Institute, Victoria, Australia.
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14
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Ruggiero SM, Xian J, Helbig I. The current landscape of epilepsy genetics: where are we, and where are we going? Curr Opin Neurol 2023; 36:86-94. [PMID: 36762645 PMCID: PMC10088099 DOI: 10.1097/wco.0000000000001141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
PURPOSE OF REVIEW In this review, we aim to analyse the progress in understanding the genetic basis of the epilepsies, as well as ongoing efforts to define the increasingly diverse and novel presentations, phenotypes and divergences from the expected that have continually characterized the field. RECENT FINDINGS A genetic workup is now considered to be standard of care for individuals with an unexplained epilepsy, due to mounting evidence that genetic diagnoses significantly influence treatment choices, prognostication, community support, and increasingly, access to clinical trials. As more individuals with epilepsy are tested, novel presentations of known epilepsy genes are being discovered, and more individuals with self-limited epilepsy are able to attain genetic diagnoses. In addition, new genes causative of epilepsy are being uncovered through both traditional and novel methods, including large international data-sharing collaborations and massive sequencing efforts as well as computational methods and analyses driven by the Human Phenotype Ontology (HPO). SUMMARY New approaches to gene discovery and characterization are advancing rapidly our understanding of the genetic and phenotypic architecture of the epilepsies. This review highlights relevant and groundbreaking studies published recently that have pushed forward the field of epilepsy genetics.
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Affiliation(s)
- Sarah M Ruggiero
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- The Epilepsy NeuroGenetics Initiative (ENGIN), Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Department of Biomedical and Health Informatics (DBHi), Children’s Hospital of Philadelphia, Philadelphia, PA, 19146, USA
| | - Julie Xian
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- The Epilepsy NeuroGenetics Initiative (ENGIN), Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Department of Biomedical and Health Informatics (DBHi), Children’s Hospital of Philadelphia, Philadelphia, PA, 19146, USA
| | - Ingo Helbig
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- The Epilepsy NeuroGenetics Initiative (ENGIN), Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Department of Biomedical and Health Informatics (DBHi), Children’s Hospital of Philadelphia, Philadelphia, PA, 19146, USA
- Department of Neurology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
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15
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Pruunsild P, Bengtson CP, Loss I, Lohrer B, Bading H. Expression of the primate-specific LINC00473 RNA in mouse neurons promotes excitability and CREB-regulated transcription. J Biol Chem 2023; 299:104671. [PMID: 37019214 DOI: 10.1016/j.jbc.2023.104671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Revised: 03/27/2023] [Accepted: 03/30/2023] [Indexed: 04/05/2023] Open
Abstract
The LINC00473 (Lnc473) gene has previously been shown to be associated with cancer and psychiatric disorders. Its expression is elevated in several types of tumors and decreased in the brains of patients diagnosed with schizophrenia or major depression. In neurons, Lnc473 transcription is strongly responsive to synaptic activity, suggesting a role in adaptive, plasticity-related mechanisms. However, the function of Lnc473 is largely unknown. Here, using a recombinant adeno-associated viral vector, we introduced a primate-specific human Lnc473 RNA into mouse primary neurons. We show that this resulted in a transcriptomic shift comprising downregulation of epilepsy-associated genes and a rise in cAMP response element binding protein (CREB) activity, which was driven by augmented CREB-regulated transcription coactivator 1 (CRTC1) nuclear localization. Moreover, we demonstrate that ectopic Lnc473 expression increased neuronal excitability as well as network excitability. These findings suggest that primates may possess a lineage-specific activity-dependent modulator of CREB-regulated neuronal excitability.
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16
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Ye Z, Bennett MF, Neal A, Laing JA, Hunn MK, Wittayacharoenpong T, Todaro M, Patel SK, Bahlo M, Kwan P, O'Brien TJ, Scheffer IE, Berkovic SF, Perucca P, Hildebrand MS. Somatic Mosaic Pathogenic Variant Gradient Detected in Trace Brain Tissue From Stereo-EEG Depth Electrodes. Neurology 2022; 99:1036-1041. [PMID: 36192176 DOI: 10.1212/wnl.0000000000201469] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 09/09/2022] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND AND OBJECTIVES Mosaic pathogenic variants restricted to the brain are increasingly recognized as a cause of focal epilepsies. We aimed to identify a mosaic pathogenic variant and its anatomical gradient in brain DNA derived from trace tissue on explanted stereoelectroencephalography (SEEG) electrodes. METHODS We studied a patient with nonlesional multifocal epilepsy undergoing presurgical evaluation with SEEG. After explantation, the electrodes were divided into 3 pools based on their brain location (right posterior quadrant, left posterior quadrant, hippocampus/temporal neocortex). Tissue from each pool was processed for trace DNA that was whole genome amplified prior to high-depth exome sequencing. Droplet digital PCR was performed to quantify mosaicism. A brain-specific glial fibrillary acidic protein (GFAP) assay enabled cell-of-origin analysis. RESULTS We demonstrated a mosaic gradient for a novel pathogenic KCNT1 loss-of-function variant (c.530G>A, p.W177X) predicted to lead to nonsense-mediated decay. Strikingly, the mosaic gradient correlated strongly with the SEEG findings because the highest variant allele frequency was in the right posterior quadrant, reflecting the most epileptogenic region on EEG studies. An elevated GFAP level indicated enrichment of brain-derived cells in SEEG cell suspension. DISCUSSION This study demonstrates a proof of concept that mosaic gradients of pathogenic variants can be established using trace tissue from explanted SEEG electrodes.
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Affiliation(s)
- Zimeng Ye
- From the Department of Medicine (Austin Health) (Z.Y., M.F.B., S.K.P., I.E.S., S.F.B., P.P., M.S.H.), University of Melbourne, Heidelberg; Population Health and Immunity Division (M.F.B., M.B.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Medical Biology (M.F.B., M.B.), The University of Melbourne, Parkville; Department of Neurology (A.N., P.K., T.J.O.B., P.P.), Royal Melbourne Hospital, Parkville; Department of Neurology (A.N., J.A.L., T.W., M.T., P.K., T.J.O.B., P.P.), Alfred Hospital, Melbourne; Department of Medicine (A.N., P.K., T.J.O.B.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurosciences (A.N., J.A.L., T.W., M.T., P.K., T.J.O.B., P.P.), The Central Clinical School, Monash University, Melbourne; Department of Neurology (A.N.), St Vincent's Hospital, Fitzroy; Department of Neurosurgery (M.K.H.), The Alfred Hospital, Melbourne; Florey Institute of Neuroscience and Mental Health (S.K.P., I.E.S.), Heidelberg; Murdoch Children's Research Institute (I.E.S., M.S.H.), Parkville; Department of Paediatrics (I.E.S.), University of Melbourne, Royal Children's Hospital, Parkville; and Bladin-Berkovic Comprehensive Epilepsy Program (S.F.B., P.P.), Department of Neurology, Austin Health, Heidelberg, Australia
| | - Mark F Bennett
- From the Department of Medicine (Austin Health) (Z.Y., M.F.B., S.K.P., I.E.S., S.F.B., P.P., M.S.H.), University of Melbourne, Heidelberg; Population Health and Immunity Division (M.F.B., M.B.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Medical Biology (M.F.B., M.B.), The University of Melbourne, Parkville; Department of Neurology (A.N., P.K., T.J.O.B., P.P.), Royal Melbourne Hospital, Parkville; Department of Neurology (A.N., J.A.L., T.W., M.T., P.K., T.J.O.B., P.P.), Alfred Hospital, Melbourne; Department of Medicine (A.N., P.K., T.J.O.B.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurosciences (A.N., J.A.L., T.W., M.T., P.K., T.J.O.B., P.P.), The Central Clinical School, Monash University, Melbourne; Department of Neurology (A.N.), St Vincent's Hospital, Fitzroy; Department of Neurosurgery (M.K.H.), The Alfred Hospital, Melbourne; Florey Institute of Neuroscience and Mental Health (S.K.P., I.E.S.), Heidelberg; Murdoch Children's Research Institute (I.E.S., M.S.H.), Parkville; Department of Paediatrics (I.E.S.), University of Melbourne, Royal Children's Hospital, Parkville; and Bladin-Berkovic Comprehensive Epilepsy Program (S.F.B., P.P.), Department of Neurology, Austin Health, Heidelberg, Australia
| | - Andrew Neal
- From the Department of Medicine (Austin Health) (Z.Y., M.F.B., S.K.P., I.E.S., S.F.B., P.P., M.S.H.), University of Melbourne, Heidelberg; Population Health and Immunity Division (M.F.B., M.B.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Medical Biology (M.F.B., M.B.), The University of Melbourne, Parkville; Department of Neurology (A.N., P.K., T.J.O.B., P.P.), Royal Melbourne Hospital, Parkville; Department of Neurology (A.N., J.A.L., T.W., M.T., P.K., T.J.O.B., P.P.), Alfred Hospital, Melbourne; Department of Medicine (A.N., P.K., T.J.O.B.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurosciences (A.N., J.A.L., T.W., M.T., P.K., T.J.O.B., P.P.), The Central Clinical School, Monash University, Melbourne; Department of Neurology (A.N.), St Vincent's Hospital, Fitzroy; Department of Neurosurgery (M.K.H.), The Alfred Hospital, Melbourne; Florey Institute of Neuroscience and Mental Health (S.K.P., I.E.S.), Heidelberg; Murdoch Children's Research Institute (I.E.S., M.S.H.), Parkville; Department of Paediatrics (I.E.S.), University of Melbourne, Royal Children's Hospital, Parkville; and Bladin-Berkovic Comprehensive Epilepsy Program (S.F.B., P.P.), Department of Neurology, Austin Health, Heidelberg, Australia
| | - Joshua A Laing
- From the Department of Medicine (Austin Health) (Z.Y., M.F.B., S.K.P., I.E.S., S.F.B., P.P., M.S.H.), University of Melbourne, Heidelberg; Population Health and Immunity Division (M.F.B., M.B.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Medical Biology (M.F.B., M.B.), The University of Melbourne, Parkville; Department of Neurology (A.N., P.K., T.J.O.B., P.P.), Royal Melbourne Hospital, Parkville; Department of Neurology (A.N., J.A.L., T.W., M.T., P.K., T.J.O.B., P.P.), Alfred Hospital, Melbourne; Department of Medicine (A.N., P.K., T.J.O.B.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurosciences (A.N., J.A.L., T.W., M.T., P.K., T.J.O.B., P.P.), The Central Clinical School, Monash University, Melbourne; Department of Neurology (A.N.), St Vincent's Hospital, Fitzroy; Department of Neurosurgery (M.K.H.), The Alfred Hospital, Melbourne; Florey Institute of Neuroscience and Mental Health (S.K.P., I.E.S.), Heidelberg; Murdoch Children's Research Institute (I.E.S., M.S.H.), Parkville; Department of Paediatrics (I.E.S.), University of Melbourne, Royal Children's Hospital, Parkville; and Bladin-Berkovic Comprehensive Epilepsy Program (S.F.B., P.P.), Department of Neurology, Austin Health, Heidelberg, Australia
| | - Martin K Hunn
- From the Department of Medicine (Austin Health) (Z.Y., M.F.B., S.K.P., I.E.S., S.F.B., P.P., M.S.H.), University of Melbourne, Heidelberg; Population Health and Immunity Division (M.F.B., M.B.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Medical Biology (M.F.B., M.B.), The University of Melbourne, Parkville; Department of Neurology (A.N., P.K., T.J.O.B., P.P.), Royal Melbourne Hospital, Parkville; Department of Neurology (A.N., J.A.L., T.W., M.T., P.K., T.J.O.B., P.P.), Alfred Hospital, Melbourne; Department of Medicine (A.N., P.K., T.J.O.B.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurosciences (A.N., J.A.L., T.W., M.T., P.K., T.J.O.B., P.P.), The Central Clinical School, Monash University, Melbourne; Department of Neurology (A.N.), St Vincent's Hospital, Fitzroy; Department of Neurosurgery (M.K.H.), The Alfred Hospital, Melbourne; Florey Institute of Neuroscience and Mental Health (S.K.P., I.E.S.), Heidelberg; Murdoch Children's Research Institute (I.E.S., M.S.H.), Parkville; Department of Paediatrics (I.E.S.), University of Melbourne, Royal Children's Hospital, Parkville; and Bladin-Berkovic Comprehensive Epilepsy Program (S.F.B., P.P.), Department of Neurology, Austin Health, Heidelberg, Australia
| | - Thanomporn Wittayacharoenpong
- From the Department of Medicine (Austin Health) (Z.Y., M.F.B., S.K.P., I.E.S., S.F.B., P.P., M.S.H.), University of Melbourne, Heidelberg; Population Health and Immunity Division (M.F.B., M.B.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Medical Biology (M.F.B., M.B.), The University of Melbourne, Parkville; Department of Neurology (A.N., P.K., T.J.O.B., P.P.), Royal Melbourne Hospital, Parkville; Department of Neurology (A.N., J.A.L., T.W., M.T., P.K., T.J.O.B., P.P.), Alfred Hospital, Melbourne; Department of Medicine (A.N., P.K., T.J.O.B.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurosciences (A.N., J.A.L., T.W., M.T., P.K., T.J.O.B., P.P.), The Central Clinical School, Monash University, Melbourne; Department of Neurology (A.N.), St Vincent's Hospital, Fitzroy; Department of Neurosurgery (M.K.H.), The Alfred Hospital, Melbourne; Florey Institute of Neuroscience and Mental Health (S.K.P., I.E.S.), Heidelberg; Murdoch Children's Research Institute (I.E.S., M.S.H.), Parkville; Department of Paediatrics (I.E.S.), University of Melbourne, Royal Children's Hospital, Parkville; and Bladin-Berkovic Comprehensive Epilepsy Program (S.F.B., P.P.), Department of Neurology, Austin Health, Heidelberg, Australia
| | - Marian Todaro
- From the Department of Medicine (Austin Health) (Z.Y., M.F.B., S.K.P., I.E.S., S.F.B., P.P., M.S.H.), University of Melbourne, Heidelberg; Population Health and Immunity Division (M.F.B., M.B.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Medical Biology (M.F.B., M.B.), The University of Melbourne, Parkville; Department of Neurology (A.N., P.K., T.J.O.B., P.P.), Royal Melbourne Hospital, Parkville; Department of Neurology (A.N., J.A.L., T.W., M.T., P.K., T.J.O.B., P.P.), Alfred Hospital, Melbourne; Department of Medicine (A.N., P.K., T.J.O.B.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurosciences (A.N., J.A.L., T.W., M.T., P.K., T.J.O.B., P.P.), The Central Clinical School, Monash University, Melbourne; Department of Neurology (A.N.), St Vincent's Hospital, Fitzroy; Department of Neurosurgery (M.K.H.), The Alfred Hospital, Melbourne; Florey Institute of Neuroscience and Mental Health (S.K.P., I.E.S.), Heidelberg; Murdoch Children's Research Institute (I.E.S., M.S.H.), Parkville; Department of Paediatrics (I.E.S.), University of Melbourne, Royal Children's Hospital, Parkville; and Bladin-Berkovic Comprehensive Epilepsy Program (S.F.B., P.P.), Department of Neurology, Austin Health, Heidelberg, Australia
| | - Sheila K Patel
- From the Department of Medicine (Austin Health) (Z.Y., M.F.B., S.K.P., I.E.S., S.F.B., P.P., M.S.H.), University of Melbourne, Heidelberg; Population Health and Immunity Division (M.F.B., M.B.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Medical Biology (M.F.B., M.B.), The University of Melbourne, Parkville; Department of Neurology (A.N., P.K., T.J.O.B., P.P.), Royal Melbourne Hospital, Parkville; Department of Neurology (A.N., J.A.L., T.W., M.T., P.K., T.J.O.B., P.P.), Alfred Hospital, Melbourne; Department of Medicine (A.N., P.K., T.J.O.B.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurosciences (A.N., J.A.L., T.W., M.T., P.K., T.J.O.B., P.P.), The Central Clinical School, Monash University, Melbourne; Department of Neurology (A.N.), St Vincent's Hospital, Fitzroy; Department of Neurosurgery (M.K.H.), The Alfred Hospital, Melbourne; Florey Institute of Neuroscience and Mental Health (S.K.P., I.E.S.), Heidelberg; Murdoch Children's Research Institute (I.E.S., M.S.H.), Parkville; Department of Paediatrics (I.E.S.), University of Melbourne, Royal Children's Hospital, Parkville; and Bladin-Berkovic Comprehensive Epilepsy Program (S.F.B., P.P.), Department of Neurology, Austin Health, Heidelberg, Australia
| | - Melanie Bahlo
- From the Department of Medicine (Austin Health) (Z.Y., M.F.B., S.K.P., I.E.S., S.F.B., P.P., M.S.H.), University of Melbourne, Heidelberg; Population Health and Immunity Division (M.F.B., M.B.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Medical Biology (M.F.B., M.B.), The University of Melbourne, Parkville; Department of Neurology (A.N., P.K., T.J.O.B., P.P.), Royal Melbourne Hospital, Parkville; Department of Neurology (A.N., J.A.L., T.W., M.T., P.K., T.J.O.B., P.P.), Alfred Hospital, Melbourne; Department of Medicine (A.N., P.K., T.J.O.B.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurosciences (A.N., J.A.L., T.W., M.T., P.K., T.J.O.B., P.P.), The Central Clinical School, Monash University, Melbourne; Department of Neurology (A.N.), St Vincent's Hospital, Fitzroy; Department of Neurosurgery (M.K.H.), The Alfred Hospital, Melbourne; Florey Institute of Neuroscience and Mental Health (S.K.P., I.E.S.), Heidelberg; Murdoch Children's Research Institute (I.E.S., M.S.H.), Parkville; Department of Paediatrics (I.E.S.), University of Melbourne, Royal Children's Hospital, Parkville; and Bladin-Berkovic Comprehensive Epilepsy Program (S.F.B., P.P.), Department of Neurology, Austin Health, Heidelberg, Australia
| | - Patrick Kwan
- From the Department of Medicine (Austin Health) (Z.Y., M.F.B., S.K.P., I.E.S., S.F.B., P.P., M.S.H.), University of Melbourne, Heidelberg; Population Health and Immunity Division (M.F.B., M.B.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Medical Biology (M.F.B., M.B.), The University of Melbourne, Parkville; Department of Neurology (A.N., P.K., T.J.O.B., P.P.), Royal Melbourne Hospital, Parkville; Department of Neurology (A.N., J.A.L., T.W., M.T., P.K., T.J.O.B., P.P.), Alfred Hospital, Melbourne; Department of Medicine (A.N., P.K., T.J.O.B.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurosciences (A.N., J.A.L., T.W., M.T., P.K., T.J.O.B., P.P.), The Central Clinical School, Monash University, Melbourne; Department of Neurology (A.N.), St Vincent's Hospital, Fitzroy; Department of Neurosurgery (M.K.H.), The Alfred Hospital, Melbourne; Florey Institute of Neuroscience and Mental Health (S.K.P., I.E.S.), Heidelberg; Murdoch Children's Research Institute (I.E.S., M.S.H.), Parkville; Department of Paediatrics (I.E.S.), University of Melbourne, Royal Children's Hospital, Parkville; and Bladin-Berkovic Comprehensive Epilepsy Program (S.F.B., P.P.), Department of Neurology, Austin Health, Heidelberg, Australia
| | - Terence J O'Brien
- From the Department of Medicine (Austin Health) (Z.Y., M.F.B., S.K.P., I.E.S., S.F.B., P.P., M.S.H.), University of Melbourne, Heidelberg; Population Health and Immunity Division (M.F.B., M.B.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Medical Biology (M.F.B., M.B.), The University of Melbourne, Parkville; Department of Neurology (A.N., P.K., T.J.O.B., P.P.), Royal Melbourne Hospital, Parkville; Department of Neurology (A.N., J.A.L., T.W., M.T., P.K., T.J.O.B., P.P.), Alfred Hospital, Melbourne; Department of Medicine (A.N., P.K., T.J.O.B.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurosciences (A.N., J.A.L., T.W., M.T., P.K., T.J.O.B., P.P.), The Central Clinical School, Monash University, Melbourne; Department of Neurology (A.N.), St Vincent's Hospital, Fitzroy; Department of Neurosurgery (M.K.H.), The Alfred Hospital, Melbourne; Florey Institute of Neuroscience and Mental Health (S.K.P., I.E.S.), Heidelberg; Murdoch Children's Research Institute (I.E.S., M.S.H.), Parkville; Department of Paediatrics (I.E.S.), University of Melbourne, Royal Children's Hospital, Parkville; and Bladin-Berkovic Comprehensive Epilepsy Program (S.F.B., P.P.), Department of Neurology, Austin Health, Heidelberg, Australia
| | - Ingrid E Scheffer
- From the Department of Medicine (Austin Health) (Z.Y., M.F.B., S.K.P., I.E.S., S.F.B., P.P., M.S.H.), University of Melbourne, Heidelberg; Population Health and Immunity Division (M.F.B., M.B.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Medical Biology (M.F.B., M.B.), The University of Melbourne, Parkville; Department of Neurology (A.N., P.K., T.J.O.B., P.P.), Royal Melbourne Hospital, Parkville; Department of Neurology (A.N., J.A.L., T.W., M.T., P.K., T.J.O.B., P.P.), Alfred Hospital, Melbourne; Department of Medicine (A.N., P.K., T.J.O.B.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurosciences (A.N., J.A.L., T.W., M.T., P.K., T.J.O.B., P.P.), The Central Clinical School, Monash University, Melbourne; Department of Neurology (A.N.), St Vincent's Hospital, Fitzroy; Department of Neurosurgery (M.K.H.), The Alfred Hospital, Melbourne; Florey Institute of Neuroscience and Mental Health (S.K.P., I.E.S.), Heidelberg; Murdoch Children's Research Institute (I.E.S., M.S.H.), Parkville; Department of Paediatrics (I.E.S.), University of Melbourne, Royal Children's Hospital, Parkville; and Bladin-Berkovic Comprehensive Epilepsy Program (S.F.B., P.P.), Department of Neurology, Austin Health, Heidelberg, Australia
| | - Samuel F Berkovic
- From the Department of Medicine (Austin Health) (Z.Y., M.F.B., S.K.P., I.E.S., S.F.B., P.P., M.S.H.), University of Melbourne, Heidelberg; Population Health and Immunity Division (M.F.B., M.B.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Medical Biology (M.F.B., M.B.), The University of Melbourne, Parkville; Department of Neurology (A.N., P.K., T.J.O.B., P.P.), Royal Melbourne Hospital, Parkville; Department of Neurology (A.N., J.A.L., T.W., M.T., P.K., T.J.O.B., P.P.), Alfred Hospital, Melbourne; Department of Medicine (A.N., P.K., T.J.O.B.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurosciences (A.N., J.A.L., T.W., M.T., P.K., T.J.O.B., P.P.), The Central Clinical School, Monash University, Melbourne; Department of Neurology (A.N.), St Vincent's Hospital, Fitzroy; Department of Neurosurgery (M.K.H.), The Alfred Hospital, Melbourne; Florey Institute of Neuroscience and Mental Health (S.K.P., I.E.S.), Heidelberg; Murdoch Children's Research Institute (I.E.S., M.S.H.), Parkville; Department of Paediatrics (I.E.S.), University of Melbourne, Royal Children's Hospital, Parkville; and Bladin-Berkovic Comprehensive Epilepsy Program (S.F.B., P.P.), Department of Neurology, Austin Health, Heidelberg, Australia
| | - Piero Perucca
- From the Department of Medicine (Austin Health) (Z.Y., M.F.B., S.K.P., I.E.S., S.F.B., P.P., M.S.H.), University of Melbourne, Heidelberg; Population Health and Immunity Division (M.F.B., M.B.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Medical Biology (M.F.B., M.B.), The University of Melbourne, Parkville; Department of Neurology (A.N., P.K., T.J.O.B., P.P.), Royal Melbourne Hospital, Parkville; Department of Neurology (A.N., J.A.L., T.W., M.T., P.K., T.J.O.B., P.P.), Alfred Hospital, Melbourne; Department of Medicine (A.N., P.K., T.J.O.B.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurosciences (A.N., J.A.L., T.W., M.T., P.K., T.J.O.B., P.P.), The Central Clinical School, Monash University, Melbourne; Department of Neurology (A.N.), St Vincent's Hospital, Fitzroy; Department of Neurosurgery (M.K.H.), The Alfred Hospital, Melbourne; Florey Institute of Neuroscience and Mental Health (S.K.P., I.E.S.), Heidelberg; Murdoch Children's Research Institute (I.E.S., M.S.H.), Parkville; Department of Paediatrics (I.E.S.), University of Melbourne, Royal Children's Hospital, Parkville; and Bladin-Berkovic Comprehensive Epilepsy Program (S.F.B., P.P.), Department of Neurology, Austin Health, Heidelberg, Australia
| | - Michael S Hildebrand
- From the Department of Medicine (Austin Health) (Z.Y., M.F.B., S.K.P., I.E.S., S.F.B., P.P., M.S.H.), University of Melbourne, Heidelberg; Population Health and Immunity Division (M.F.B., M.B.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Medical Biology (M.F.B., M.B.), The University of Melbourne, Parkville; Department of Neurology (A.N., P.K., T.J.O.B., P.P.), Royal Melbourne Hospital, Parkville; Department of Neurology (A.N., J.A.L., T.W., M.T., P.K., T.J.O.B., P.P.), Alfred Hospital, Melbourne; Department of Medicine (A.N., P.K., T.J.O.B.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurosciences (A.N., J.A.L., T.W., M.T., P.K., T.J.O.B., P.P.), The Central Clinical School, Monash University, Melbourne; Department of Neurology (A.N.), St Vincent's Hospital, Fitzroy; Department of Neurosurgery (M.K.H.), The Alfred Hospital, Melbourne; Florey Institute of Neuroscience and Mental Health (S.K.P., I.E.S.), Heidelberg; Murdoch Children's Research Institute (I.E.S., M.S.H.), Parkville; Department of Paediatrics (I.E.S.), University of Melbourne, Royal Children's Hospital, Parkville; and Bladin-Berkovic Comprehensive Epilepsy Program (S.F.B., P.P.), Department of Neurology, Austin Health, Heidelberg, Australia.
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Rychkov GY, Shaukat Z, Lim CX, Hussain R, Roberts BJ, Bonardi CM, Rubboli G, Meaney BF, Whitney R, Møller RS, Ricos MG, Dibbens LM. Functional Effects of Epilepsy Associated KCNT1 Mutations Suggest Pathogenesis via Aberrant Inhibitory Neuronal Activity. Int J Mol Sci 2022; 23:ijms232315133. [PMID: 36499459 PMCID: PMC9740882 DOI: 10.3390/ijms232315133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 11/28/2022] [Accepted: 11/29/2022] [Indexed: 12/05/2022] Open
Abstract
KCNT1 (K+ channel subfamily T member 1) is a sodium-activated potassium channel highly expressed in the nervous system which regulates neuronal excitability by contributing to the resting membrane potential and hyperpolarisation following a train of action potentials. Gain of function mutations in the KCNT1 gene are the cause of neurological disorders associated with different forms of epilepsy. To gain insights into the underlying pathobiology we investigated the functional effects of 9 recently published KCNT1 mutations, 4 previously studied KCNT1 mutations, and one previously unpublished KCNT1 variant of unknown significance. We analysed the properties of KCNT1 potassium currents and attempted to find a correlation between the changes in KCNT1 characteristics due to the mutations and severity of the neurological disorder they cause. KCNT1 mutations identified in patients with epilepsy were introduced into the full length human KCNT1 cDNA using quick-change site-directed mutagenesis protocol. Electrophysiological properties of different KCNT1 constructs were investigated using a heterologous expression system (HEK293T cells) and patch clamping. All mutations studied, except T314A, increased the amplitude of KCNT1 currents, and some mutations shifted the voltage dependence of KCNT1 open probability, increasing the proportion of channels open at the resting membrane potential. The T314A mutation did not affect KCNT1 current amplitude but abolished its voltage dependence. We observed a positive correlation between the severity of the neurological disorder and the KCNT1 channel open probability at resting membrane potential. This suggests that gain of function KCNT1 mutations cause epilepsy by increasing resting potassium conductance and suppressing the activity of inhibitory neurons. A reduction in action potential firing in inhibitory neurons due to excessively high resting potassium conductance leads to disinhibition of neural circuits, hyperexcitability and seizures.
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Affiliation(s)
- Grigori Y. Rychkov
- Clinical and Health Sciences, Australian Centre for Precision Health, University of South Australia, Adelaide, SA 5000, Australia
- School of Biomedicine, University of Adelaide, Adelaide, SA 5005, Australia
- South Australian Health and Medical Research Institute, Adelaide, SA 5005, Australia
- Correspondence:
| | - Zeeshan Shaukat
- Clinical and Health Sciences, Australian Centre for Precision Health, University of South Australia, Adelaide, SA 5000, Australia
| | - Chiao Xin Lim
- Clinical and Health Sciences, Australian Centre for Precision Health, University of South Australia, Adelaide, SA 5000, Australia
| | - Rashid Hussain
- Clinical and Health Sciences, Australian Centre for Precision Health, University of South Australia, Adelaide, SA 5000, Australia
| | - Ben J. Roberts
- Clinical and Health Sciences, Health and Biomedical Innovation, University of South Australia, Adelaide, SA 5000, Australia
| | - Claudia M. Bonardi
- Department of Woman’s and Child’s Health, Padua University Hospital, 35128 Padua, Italy
- The Danish Epilepsy Centre, 4293 Dianalund, Denmark
| | - Guido Rubboli
- Denmark Department of Clinical Medicine, Copenhagen University Hospital, 2200 Copenhagen, Denmark
| | - Brandon F. Meaney
- Division of Neurology, Department of Paediatrics, McMaster University, Hamilton, ON 8SL 4L8, Canada
| | - Robyn Whitney
- Division of Neurology, Department of Paediatrics, McMaster University, Hamilton, ON 8SL 4L8, Canada
| | - Rikke S. Møller
- Department of Epilepsy Genetics and Personalized Treatment, Member of the ERN EpiCARE, The Danish Epilepsy Centre, 4293 Dianalund, Denmark
- Department of Regional Health Research, University of Southern Denmark, 5000 Odense, Denmark
| | - Michael G. Ricos
- Clinical and Health Sciences, Australian Centre for Precision Health, University of South Australia, Adelaide, SA 5000, Australia
| | - Leanne M. Dibbens
- Clinical and Health Sciences, Australian Centre for Precision Health, University of South Australia, Adelaide, SA 5000, Australia
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18
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Miziak B, Czuczwar SJ. Approaches for the discovery of drugs that target K Na 1.1 channels in KCNT1-associated epilepsy. Expert Opin Drug Discov 2022; 17:1313-1328. [PMID: 36408599 DOI: 10.1080/17460441.2023.2150164] [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: 11/22/2022]
Abstract
INTRODUCTION There are approximately 70 million people with epilepsy and about 30% of patients are not satisfactorily treated. A link between gene mutations and epilepsy is well documented. A number of pathological variants of KCNT1 gene (encoding the weakly voltage-dependent sodium-activated potassium channel - KNa 1.1) mutations has been found. For instance, epilepsy of infancy with migrating focal seizures, autosomal sleep-related hypermotor epilepsy or Ohtahara syndrome have been associated with KCNT1 gene mutations. AREAS COVERED Several methods for studies on KNa 1.1 channels have been reviewed - patch clamp analysis, Förster resonance energy transfer spectroscopy and whole-exome sequencing. The authors also review available drugs for the management of KCNT1 epilepsies. EXPERT OPINION The current methods enable deeper insights into electrophysiology of KNa 1.1 channels or its functioning in different activation states. It is also possible to identify a given KCNT1 mutation. Quinidine and cannabidiol show variable efficacy as add-on to baseline antiepileptic drugs so more effective treatments are required. A combined approach with the methods shown above, in silico methods and the animal model of KCNT1 epilepsies seems likely to create personalized treatment of patients with KCNT1 gene mutations.
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Affiliation(s)
- Barbara Miziak
- Department of Pathophysiology, Medical University of Lublin, Lublin, Poland
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Wang M, Geng G, Meng Y, Zhang H, Gao Z, Shi J. Long-term follow-up of vagus nerve stimulation in drug-resistant KCNT1-related epilepsy: a case presentation. ACTA EPILEPTOLOGICA 2022. [DOI: 10.1186/s42494-022-00105-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Abstract
Background
The KCNT1 gene encodes a Na+-activated K+ channel. Gain-of-function mutations of KCNT1 lead to autosomal dominant sleep-related hypermotor epilepsy, early-onset epileptic encephalopathy, focal epilepsy and other epileptic encephalopathies. In this paper, we report a boy carrying a KCNT1 gene mutation, who presented with drug-resistant focal-onset seizures. He had decreased seizure frequency and improvement of background changes in electroencephalography (EEG) after vagus nerve stimulation (VNS).
Case presentation
The case was a nonverbal 9-year-old male who presented with drug-resistant focal-onset seizures since age 3 and had underwent VNS therapy for 2 years. He had hypermotor symptoms, automatism and bilateral asymmetric tonic seizures with cognitive decline and aphasis from age 3. The patient had a variety of seizure types that only occurred at night. The most common seizure type was automatisms, and ictal video EEG showed high-amplitude delta waves, followed by a fast rhythmic sharp activity in the mesial frontal and bitemporal regions. The patient was diagnosed with KCNT1-related epilepsy, epileptic encephalopathy and cognitive disorder. He was refractory to multiple anti-seizure medicines (ASM) and ketogenic diet. After VNS treatment at age 7, the frequency of seizures was reduced significantly and EEG was improved in background slowing.
Conclusions
Children with KCNT1-related epilepsy usually have early onset of disease, are nonverbal, and are refractory to ASM. This boy with drug-resistant KCNT1-related epilepsy showed significantly reduced seizure frequency after VNS. This report may provide reference for management of cases of KCNT1-related epilepsy.
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Incidence of Aicardi-Goutières syndrome and KCNT1-related epilepsy in Denmark. Mol Genet Metab Rep 2022; 33:100924. [PMID: 36262748 PMCID: PMC9574483 DOI: 10.1016/j.ymgmr.2022.100924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 10/07/2022] [Accepted: 10/08/2022] [Indexed: 11/06/2022] Open
Abstract
Objective To estimate the incidence of Aicardi-Goutières syndrome (AGS) and potassium sodium-activated channel subfamily T member 1 (KCNT1)-related epilepsy in Denmark and to characterize the patients diagnosed with AGS and KCNT1-related epilepsy. Background AGS and KCNT1-related epilepsy are 2 distinct rare genetic disorders. Due to the rarity of AGS and KCNT1-related epilepsy, the epidemiology remains unclear. The incidences for these diseases or the carriers with disease-related genetic variants remain unknown. Materials and methods This is a retrospective, non-interventional, population-based study using aggregate data from the Danish population register and hospital-based patient-level data in Denmark to identify persons with genetically confirmed AGS between January 2010 to December 2020 and KCNT1-related epilepsies between January 2012 to December 2020. Cases of these disorders were identified from in-hospital databases, and pathogenic variants were identified and confirmed by Sanger and/or whole exome (panel-based) sequencing. The incidence of AGS and KCNT1-related epilepsy were estimated in separate statistical analyses. Results A total of 7 AGS patients were identified. The mean age at AGS diagnosis was 19.4 months (median age 14 months). TREX1 (n < 5) and RNASEH2B (n ≥ 5) genes were reported with confirmed pathogenic variants. The birth incidence of AGS was <0.7600 per 100,000 live births. The average annual incidence rate was calculated as 0.0539 (95% CI: 0.0217–0.1111) per 100,000 persons per year in the total population < 18 years (n = 7); the average annual incidence rate was <0.7538 per 100,000 persons per year (n < 5) in the population < 12 months, and the average annual incidence rate in the population ≥ 12 months and < 18 years was <0.0406 per 100,000 persons per year (n < 5). A total of 14 KCNT1-related epilepsy cases were identified during the study period (n = 5 in 2016, remaining 9 cases in 2013 and 2015). The mean age at diagnosis was 20.6 years (median 19 years) for KCNT1 cases. A total of 8 cases (57.1%) were ≥ 18 years, and 6 (42.9%) were < 18 years at diagnosis. The phenotype autosomal dominant or sporadic sleep-related hypermotor epilepsy (ADSHE) (n = 10, 71.4%) was most reported; the remaining 4 cases had either epilepsy of infancy with migrating focal seizures (EIMFS) or an unclassifiable developmental and epileptic encephalopathy (DEE). The birth incidence of KCNT1-related epilepsy was ≤1.1205 per 100,000 live births. The average annual incidence rates per 100,000 persons per year during the study period were 0.0431 (95% confidence interval [CI]: 0.0236–0.0723; n = 14) in the overall population ≤ 50 years, 0.0568 (95% CI: 0.0209–0.1237; n = 6) in the population < 18 years, and 0.0365 (95% CI: 0.0157–0.0718; n = 8) in the population ≥ 18 and ≤ 50 years. There were 3 families with at least 2 cases diagnosed with KCNT1-related epilepsies (on average 3.3 cases per family), indicating 10 cases in total within the 3 families. All KCNT1 cases of ADSHE phenotype came from the 3 families. The higher incidence of older ages and ADSHE cases compared with previous KCNT1 studies is likely due to the capture of prevalent and familial previously undiagnosed cases. Excluding these family cases, the average annual incidence was 0.0123 (95% CI: 0.0034–0.0315, n = 4) per 100,000 persons per year in the population ≤ 50 years during 2012–2020. Conclusions AGS and KCNT1-related epilepsy are particularly rare diseases. The annual average incidence rate of AGS was 0.0539 per 100,000 persons per year in the population < 18 years and birth incidence was <0.7600 per 100,000 live births during 2010–2020. The average annual incidence rate of KCNT1-related epilepsy was 0.0431 per 100,000 persons per year in the population ≤ 50 years and the birth incidence was ≤1.1205 per 100,000 live births during 2012–2020. Given similar healthcare systems and genetic pools, these findings may provide insight on the incidence of these rare diseases in the Nordics.
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Syrbe S. Developmental and epileptic encephalopathies - therapeutic consequences of genetic testing. MED GENET-BERLIN 2022; 34:215-224. [PMID: 38835873 PMCID: PMC11006352 DOI: 10.1515/medgen-2022-2145] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2024]
Abstract
Developmental and epileptic encephalopathies comprise a heterogeneous group of monogenic neurodevelopmental disorders characterized by early-onset seizures, marked epileptic activity and abnormal neurocognitive development. The identification of an increasing number of underlying genetic alterations and their pathophysiological roles in cellular signaling drives the way toward novel precision therapies. The implementation of novel treatments that target the underlying mechanisms gives hope for disease modification that will improve not only the seizure burden but also the neurodevelopmental outcome of affected children. So far, beneficial effects are mostly reported in individual trials and small numbers of patients. There is a need for international collaborative studies to define the natural history and relevant outcome measures and to test novel pharmacological approaches.
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Affiliation(s)
- Steffen Syrbe
- Division of Paediatric Epileptology, Centre for Paediatrics and Adolescent Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany
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22
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Liu HF, Yuan TY, Yang JW, Li F, Wang F, Fu HM. A novel de novo heterozygous variant of the KCNQ2 gene: Contribution to early‑onset epileptic encephalopathy in a female infant. Mol Med Rep 2022; 26:282. [PMID: 35856407 PMCID: PMC9364154 DOI: 10.3892/mmr.2022.12797] [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: 12/25/2021] [Accepted: 06/29/2022] [Indexed: 11/16/2022] Open
Abstract
Early-onset epileptic encephalopathy (EOEE) represents one of the most severe epilepsies, characterized by recurrent seizures during early infancy, electroencephalogram (EEG) abnormalities and varying degrees of neurodevelopmental delay. The KCNQ2 gene has been reported to have a major role in EOEE. In the present study, a 3-month-old female infant from the Chinese Lisu minority with EOEE was analyzed. Detailed clinical evaluations and next-generation sequencing were performed to investigate the clinical and genetic characteristics of this patient, respectively. Furthermore, the three-dimensional structure of the mutant protein was predicted by SWISS-Model and the expression of KCNQ2 protein in the patient was assessed by flow cytometry. It was observed that the patient presented with typical clinical features of EOEE, including repeated non-febrile seizures and significant EEG abnormalities. A novel heterozygous missense variant c.431G>C (p.R144P) in KCNQ2 was identified in the patient and the genotyping of KCNQ2 in the patient's parents suggested that this variant was de novo. Subsequently, the breakage of hydrogen bonds between certain amino acids was predicted by structural analysis of the mutant protein. Flow cytometric analysis detected a significant reduction buts not complete loss of native KCNQ2 protein expression in the patient (25.1%). In conclusion, a novel variant in KCNQ2 was confirmed as the genetic cause for EOEE in this patient. The present study expanded the pathogenic mutation spectrum of KCNQ2, enhanced the understanding of the molecular pathogenesis of EOEE and provided novel clues for research on the genotype-phenotype correlation in this disease.
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Affiliation(s)
- Hai-Feng Liu
- Department of Pulmonary and Critical Care Medicine, Kunming Children's Hospital and Yunnan Key Laboratory of Children's Major Disease Research, Kunming, Yunnan 650034, P.R. China
| | - Ting-Yun Yuan
- Department of Pulmonary and Critical Care Medicine, Kunming Children's Hospital and Yunnan Key Laboratory of Children's Major Disease Research, Kunming, Yunnan 650034, P.R. China
| | - Jia-Wu Yang
- Department of Pulmonary and Critical Care Medicine, Kunming Children's Hospital and Yunnan Key Laboratory of Children's Major Disease Research, Kunming, Yunnan 650034, P.R. China
| | - Feng Li
- Department of Pulmonary and Critical Care Medicine, Kunming Children's Hospital and Yunnan Key Laboratory of Children's Major Disease Research, Kunming, Yunnan 650034, P.R. China
| | - Fan Wang
- Department of Pulmonary and Critical Care Medicine, Kunming Children's Hospital and Yunnan Key Laboratory of Children's Major Disease Research, Kunming, Yunnan 650034, P.R. China
| | - Hong-Min Fu
- Department of Pulmonary and Critical Care Medicine, Kunming Children's Hospital and Yunnan Key Laboratory of Children's Major Disease Research, Kunming, Yunnan 650034, P.R. China
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23
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Lu J, Zhao G, Lv D, Cao L, Zhao G. Autosomal dominant sleep-related hypermotor epilepsy associated with a novel mutation of KCNT1. Transl Neurosci 2022; 13:240-245. [PMID: 36117860 PMCID: PMC9438967 DOI: 10.1515/tnsci-2022-0241] [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: 06/18/2022] [Revised: 08/08/2022] [Accepted: 08/09/2022] [Indexed: 11/24/2022] Open
Abstract
Autosomal dominant sleep-related hypermotor epilepsy (ADSHE) is characterized by severe sleep-related rigid hypermotor seizures. The pathogenic genes of ADSHE include genes encoding subunits of the neuronal nicotinic acetylcholine receptor, KCNT1, DEPDC5, NPRL2/3, CABP4, and CRH. Individuals with KCNT1-related ADSHE are more likely to develop seizures at a younger age, have cognitive comorbidity, and display psychiatric and behavioral problems. In this study, a 12-year-old Chinese girl was referred for genetic evaluation of grand mal seizures. She had paroxysmal convulsions of the limbs and loss of consciousness just after falling asleep without obvious triggers. A novel heterozygous missense mutation c.2797C > T (p.Arg933Cys) in exon 24 of the KCNT1 was identified in the proband by whole-exome sequencing and Sanger sequencing, and the clinical symptoms were compatible with ADSHE. The proband’s father has been showing similar symptoms for more than 20 years and had the same site mutation. Her mother and sister were physically and genetically normal. The study revealed a novel variant in the KCNT1 and expanded the mutation spectrum for this clinical condition. Our results provide further evidence supporting a causative role in KCNT1 variants in ADSHE.
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Affiliation(s)
- Jinyu Lu
- Department of Neurology, The Fourth Affiliated Hospital, Zhejiang University School of Medicine , Yiwu , China
| | - Gaohua Zhao
- Department of Neurology, The Fourth Affiliated Hospital, Zhejiang University School of Medicine , Yiwu , China
| | - Dayao Lv
- Department of Neurology, The Fourth Affiliated Hospital, Zhejiang University School of Medicine , Yiwu , China
| | - Lanxiao Cao
- Department of Neurology, The Fourth Affiliated Hospital, Zhejiang University School of Medicine , Yiwu , China
| | - Guohua Zhao
- Department of Neurology, The Fourth Affiliated Hospital, Zhejiang University School of Medicine , Yiwu , China
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24
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Xu D, Chen S, Yang J, Wang X, Fang Z, Li M. Precision therapy with quinidine of KCNT1-related epileptic disorders: a systematic review. Br J Clin Pharmacol 2022; 88:5096-5112. [PMID: 35940594 DOI: 10.1111/bcp.15479] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 07/04/2022] [Accepted: 07/27/2022] [Indexed: 11/27/2022] Open
Abstract
AIMS Despite numerous studies on quinidine therapies for epilepsies associated with KCNT1 gene mutations, there is no consensus on its clinical utility. Thus, we reviewed studies evaluating the efficacy and safety of quinidine in KCNT1-related epileptic disorders. METHODS Electronic databases were queried for in vivo and in vitro studies on quinidine therapy in KCNT1-related epilepsies published on or before May 1st, 2022. The evaluation of evidence was done as per the American Academy of Neurology's classification scheme. Identification of significant factors that possibly influenced therapeutic effects of quinidine were performed using χ2 tests. RESULTS Twenty-seven studies containing 82 patient records were reviewed. Records of eighty patients with 33 KCNT1 mutations were analyzed, of which 20 patients had gained ≥50% seizure reduction due to quinidine therapy. However, quinidine therapy often had different effects on patients with the same KCNT1 mutation. Age, genotypes of KCNT1 mutations, seizure types and brain MRI did not significantly influence the therapeutic effect of quinidine. Prolonged QTc was the most common among all adverse events with quinidine. Notably, results of in vitro quinidine tests did not correspond with in vivo tests. CONCLUSIONS Therapeutic effects of quinidine on KCNT1-related epilepsies remained indefinite as contradictory results were detected in similar patients. Age, seizure types, genotypes of KCNT1 mutations and brain MRI did not influence the therapeutic effects of quinidine. Insensitivity to quinidine by a certain Kcnt1 genotype in molecular tests predictive of its inefficacy in human populations of the respective mutation.
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Affiliation(s)
- Da Xu
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Shuang Chen
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jun Yang
- Department of neurology, Xiangyang No.1 People's Hospital, Hubei University of Medicine, Xiangyang, China
| | - Xiufeng Wang
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhi Fang
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Man Li
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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25
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Joshi C. Zeroing in on Phenotypes While Also Broadening Our Understanding of KCNT1-Related Epilepsy. Epilepsy Curr 2022; 22:291-293. [PMID: 36285205 PMCID: PMC9549234 DOI: 10.1177/15357597221096002] [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: 11/18/2022] Open
Abstract
KCNT1-Related Epilepsies and Epileptic Encephalopathies: Phenotypic and
Mutational Spectrum Bonardi CM, Heyne HO, Fiannacca M, et al. Brain. 2021;144(12):
3635-3650. doi:10.1093/brain/awab219. Variants in KCNT1, encoding a sodium-gated potassium channel (subfamily T member 1),
have been associated with a spectrum of epilepsies and neurodevelopmental disorders.
These range from familial autosomal dominant or sporadic sleep-related hypermotor
epilepsy to epilepsy of infancy with migrating focal seizures (EIMFS) and include
developmental and epileptic encephalopathies. This study aims to provide a
comprehensive overview of the phenotypic and genotypic spectrum of KCNT1
mutation-related epileptic disorders in 248 individuals, including 66 previously
unpublished and 182 published cases, the largest cohort reported so far. Four
phenotypic groups emerged from our analysis: (i) EIMFS (152 individuals, 33 previously
unpublished); (ii) developmental and epileptic encephalopathies other than EIMFS
(non-EIMFS developmental and epileptic encephalopathies) (37 individuals, 17
unpublished); (iii) autosomal dominant or sporadic sleep-related hypermotor epilepsy
(53 patients, 14 unpublished); and (iv) other phenotypes (6 individuals, 2
unpublished). In our cohort of 66 new cases, the most common phenotypic features were:
(i) in EIMFS, heterogeneity of seizure types, including epileptic spasms, epilepsy
improvement over time, no epilepsy-related deaths; (ii) in non-EIMFS developmental and
epileptic encephalopathies, possible onset with West syndrome, occurrence of atypical
absences, possible evolution to developmental and epileptic encephalopathies with
sleep-related hypermotor epilepsy features; one case of sudden unexplained death in
epilepsy; (iii) in autosomal dominant or sporadic sleep-related hypermotor epilepsy,
we observed a high prevalence of drug-resistance, although seizure frequency improved
with age in some individuals, appearance of cognitive regression after seizure onset
in all patients, no reported severe psychiatric disorders, although
behavioral/psychiatric comorbidities were reported in ∼50% of the patients, sudden
unexplained death in epilepsy in one individual; and (iv) other phenotypes in
individuals with mutation of KCNT1 included temporal lobe epilepsy, and epilepsy with
tonic–clonic seizures and cognitive regression. Genotypic analysis of the whole cohort
of 248 individuals showed only missense mutations and one inframe deletion in KCNT1.
Although the KCNT1 mutations in affected individuals were seen to be distributed among
the different domains of the KCNT1 protein, genotype–phenotype considerations showed
many of the autosomal dominant or sporadic sleep-related hypermotor
epilepsy-associated mutations to be clustered around the RCK2 domain in the C
terminus, distal to the NADP domain. Mutations associated with EIMFS/non-EIMFS
developmental and epileptic encephalopathies did not show a particular pattern of
distribution in the KCNT1 protein. Recurrent KCNT1 mutations were seen to be
associated with both severe and less severe phenotypes. Our study further defines and
broadens the phenotypic and genotypic spectrums of KCNT1-related epileptic conditions
and emphasizes the increasingly important role of this gene in the pathogenesis of
early onset developmental and epileptic encephalopathies as well as of focal
epilepsies, namely autosomal dominant or sporadic sleep-related hypermotor
epilepsy.
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Affiliation(s)
- Charuta Joshi
- Department of Neurology, Children's Hospital Colorado, Aurora, CO, USA
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26
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Fu Y, Lorrai I, Zorman B, Mercatelli D, Shankula C, Marquez Gaytan J, Lefebvre C, de Guglielmo G, Kim HR, Sumazin P, Giorgi FM, Repunte-Canonigo V, Sanna PP. Escalated (Dependent) Oxycodone Self-Administration Is Associated with Cognitive Impairment and Transcriptional Evidence of Neurodegeneration in Human Immunodeficiency Virus (HIV) Transgenic Rats. Viruses 2022; 14:669. [PMID: 35458399 PMCID: PMC9030762 DOI: 10.3390/v14040669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Revised: 03/02/2022] [Accepted: 03/09/2022] [Indexed: 02/05/2023] Open
Abstract
Substance use disorder is associated with accelerated disease progression in people with human immunodeficiency virus (HIV; PWH). Problem opioid use, including high-dose opioid therapy, prescription drug misuse, and opioid abuse, is high and increasing in the PWH population. Oxycodone is a broadly prescribed opioid in both the general population and PWH. Here, we allowed HIV transgenic (Tg) rats and wildtype (WT) littermates to intravenously self-administer oxycodone under short-access (ShA) conditions, which led to moderate, stable, "recreational"-like levels of drug intake, or under long-access (LgA) conditions, which led to escalated (dependent) drug intake. HIV Tg rats with histories of oxycodone self-administration under LgA conditions exhibited significant impairment in memory performance in the novel object recognition (NOR) paradigm. RNA-sequencing expression profiling of the medial prefrontal cortex (mPFC) in HIV Tg rats that self-administered oxycodone under ShA conditions exhibited greater transcriptional evidence of inflammation than WT rats that self-administered oxycodone under the same conditions. HIV Tg rats that self-administered oxycodone under LgA conditions exhibited transcriptional evidence of an increase in neuronal injury and neurodegeneration compared with WT rats under the same conditions. Gene expression analysis indicated that glucocorticoid-dependent adaptations contributed to the gene expression effects of oxycodone self-administration. Overall, the present results indicate that a history of opioid intake promotes neuroinflammation and glucocorticoid dysregulation, and excessive opioid intake is associated with neurotoxicity and cognitive impairment in HIV Tg rats.
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Affiliation(s)
- Yu Fu
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, San Diego, CA 92037, USA; (Y.F.); (I.L.); (C.S.); (J.M.G.); (C.L.)
- European Bioinformatics Institute (EMBL-EBI), Hinxton CB10 1SD, UK
| | - Irene Lorrai
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, San Diego, CA 92037, USA; (Y.F.); (I.L.); (C.S.); (J.M.G.); (C.L.)
| | - Barry Zorman
- Department of Pediatrics, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX 77030, USA; (B.Z.); (H.R.K.); (P.S.)
| | - Daniele Mercatelli
- Department of Pharmacy and Biotechnology, University of Bologna, 40126 Bologna, Italy; (D.M.); (F.M.G.)
| | - Chase Shankula
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, San Diego, CA 92037, USA; (Y.F.); (I.L.); (C.S.); (J.M.G.); (C.L.)
| | - Jorge Marquez Gaytan
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, San Diego, CA 92037, USA; (Y.F.); (I.L.); (C.S.); (J.M.G.); (C.L.)
| | - Celine Lefebvre
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, San Diego, CA 92037, USA; (Y.F.); (I.L.); (C.S.); (J.M.G.); (C.L.)
- 92160 Antony, France
| | - Giordano de Guglielmo
- Department of Psychiatry, University of California, La Jolla, San Diego, CA 92093, USA;
| | - Hyunjae Ryan Kim
- Department of Pediatrics, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX 77030, USA; (B.Z.); (H.R.K.); (P.S.)
| | - Pavel Sumazin
- Department of Pediatrics, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX 77030, USA; (B.Z.); (H.R.K.); (P.S.)
| | - Federico M. Giorgi
- Department of Pharmacy and Biotechnology, University of Bologna, 40126 Bologna, Italy; (D.M.); (F.M.G.)
| | - Vez Repunte-Canonigo
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, San Diego, CA 92037, USA; (Y.F.); (I.L.); (C.S.); (J.M.G.); (C.L.)
| | - Pietro Paolo Sanna
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, San Diego, CA 92037, USA; (Y.F.); (I.L.); (C.S.); (J.M.G.); (C.L.)
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27
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Yang Z, Cao J, Song Y, Li S, Jiao Z, Ren S, Gao X, Zhang S, Liu J, Chen Y. Whole-exome sequencing identified novel variants in three Chinese Leigh syndrome pedigrees. Am J Med Genet A 2022; 188:1214-1225. [PMID: 35014173 DOI: 10.1002/ajmg.a.62641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 12/12/2021] [Accepted: 12/18/2021] [Indexed: 11/08/2022]
Abstract
Leigh syndrome (LS), the most common mitochondrial disease in early childhood, usually manifests variable neurodegenerative symptoms and typical brain magnetic resonance imaging (MRI) lesions. To date, pathogenic variants in more than 80 genes have been identified. However, there are still many cases without molecular diagnoses, and thus more disease-causing variants need to be unveiled. Here, we presented three clinically suspected LS patients manifesting neurological symptoms including developmental delay, hypotonia, and epilepsy during the first year of age, along with symmetric brain lesions on MRI. We explored disease-associated variants in patients and their nonconsanguineous parents by whole-exome sequencing and subsequent Sanger sequencing verification. Sequencing data revealed three pairs of disease-associated compound heterozygous variants: c.1A>G (p.Met1?) and 409G>C (p.Asp137His) in SDHA, c.1253G>A (p.Arg418His) and 1300C>T (p.Leu434Phe) in NARS2, and c.5C>T (p.Ala2Val) and 773T>G (p.Leu258Trp) in ECHS1. Among them, the likely pathogenic variants c.409G>C (p.Asp137His) in SDHA, c.1300C>T (p.Leu434Phe) in NARS2, and c.773T>G (p.Leu258Trp) in ECHS1 were newly identified. Segregation analysis indicated the possible disease-causing nature of the novel variants. In silico prediction and three-dimensional protein modeling further suggested the potential pathogenicity of these variants. Our discovery of novel variants expands the gene variant spectrum of LS and provides novel evidence for genetic counseling.
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Affiliation(s)
- Zhihua Yang
- Genetic and Prenatal Diagnosis Center, Department of Gynecology and Obstetrics, First Affiliated Hospital, Zhengzhou University, Zhengzhou, China
| | - Jun Cao
- Genetic and Prenatal Diagnosis Center, Department of Gynecology and Obstetrics, First Affiliated Hospital, Zhengzhou University, Zhengzhou, China
| | - Yucen Song
- Genetic and Prenatal Diagnosis Center, Department of Gynecology and Obstetrics, First Affiliated Hospital, Zhengzhou University, Zhengzhou, China
| | - Suyi Li
- Genetic and Prenatal Diagnosis Center, Department of Gynecology and Obstetrics, First Affiliated Hospital, Zhengzhou University, Zhengzhou, China
| | - Zhihui Jiao
- Genetic and Prenatal Diagnosis Center, Department of Gynecology and Obstetrics, First Affiliated Hospital, Zhengzhou University, Zhengzhou, China
| | - Shumin Ren
- Genetic and Prenatal Diagnosis Center, Department of Gynecology and Obstetrics, First Affiliated Hospital, Zhengzhou University, Zhengzhou, China
| | - Xu Gao
- Genetic and Prenatal Diagnosis Center, Department of Gynecology and Obstetrics, First Affiliated Hospital, Zhengzhou University, Zhengzhou, China
| | - Suqin Zhang
- Department of Pediatrics, First Affiliated Hospital, Zhengzhou University, Zhengzhou, China
| | - Jingjing Liu
- Department of MR Imaging, First Affiliated Hospital, Zhengzhou University, Zhengzhou, China
| | - Yibing Chen
- Genetic and Prenatal Diagnosis Center, Department of Gynecology and Obstetrics, First Affiliated Hospital, Zhengzhou University, Zhengzhou, China
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28
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Cherian C, Appendino JP, Ashtiani S, Federico P, Molnar CP, Kerr M, Khan A, Au PYB, Klein KM. The phenotypic spectrum of KCNT1: a new family with variable epilepsy syndromes including mild focal epilepsy. J Neurol 2021; 269:2162-2171. [PMID: 34537872 DOI: 10.1007/s00415-021-10808-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 09/13/2021] [Accepted: 09/14/2021] [Indexed: 11/27/2022]
Abstract
BACKGROUND AND OBJECTIVE Pathogenic variants in KCNT1 have been associated with severe forms of epilepsy, typically sleep-related hypermotor epilepsy or epilepsy of infancy with migrating focal seizures. To show that pathogenic variants in KCNT1 can be associated with mild extra-frontal epilepsy, we report a KCNT1 family with a wide spectrum of phenotypes ranging from developmental and epileptic encephalopathy to mild focal epilepsy without cognitive regression and not consistent with sleep-related hypermotor epilepsy. METHODS A large Canadian family of Caucasian descent including 9 affected family members was recruited. Family members were phenotyped by direct interview and review of existing medical records. Clinical epilepsy gene panel analysis and exome sequencing were performed. RESULTS Phenotypic information was available for five family members of which two had developmental and epileptic encephalopathy and three had normal development and focal epilepsy with presumed extra-frontal onset. All three had predominantly nocturnal seizures that did not show hyperkinetic features. All three reported clusters of seizures at night with a feeling of being unable to breathe associated with gasping for air, choking and/or repetitive swallowing possibly suggesting insular or opercular involvement. Genetic analysis identified a heterozygous KCNT1 c.2882G > A, p.Arg961His variant that was predicted to be deleterious. DISCUSSION This family demonstrates that the phenotypic spectrum associated with KCNT1 pathogenic variants is broader than previously assumed. Our findings indicate that variants in KCNT1 can be associated with mild focal epilepsy and should not be excluded during variant interpretation in such patients based solely on gene-disease validity.
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Affiliation(s)
- Christina Cherian
- Department of Clinical Neurosciences, Cumming School of Medicine, Foothills Medical Centre, University of Calgary, 1403 29 Street NW, Calgary, AB, T2N 2T9, Canada
| | - Juan P Appendino
- Division of Clinical Neuroscience, Department of Pediatrics, Cumming School of Medicine, Alberta Children's Hospital, University of Calgary, Calgary, AB, Canada
| | - Setareh Ashtiani
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Paolo Federico
- Department of Clinical Neurosciences, Cumming School of Medicine, Foothills Medical Centre, University of Calgary, 1403 29 Street NW, Calgary, AB, T2N 2T9, Canada.,Cumming School of Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.,Department of Radiology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Seaman Family MR Research Centre, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Christine P Molnar
- Department of Radiology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Marina Kerr
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada
| | - Aneal Khan
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada
| | - Ping Yee Billie Au
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada
| | - Karl Martin Klein
- Department of Clinical Neurosciences, Cumming School of Medicine, Foothills Medical Centre, University of Calgary, 1403 29 Street NW, Calgary, AB, T2N 2T9, Canada. .,Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada. .,Cumming School of Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada. .,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada. .,Department of Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada. .,Epilepsy Center Frankfurt Rhine-Main, Department of Neurology, Center of Neurology and Neurosurgery, University Hospital, Goethe-University, Frankfurt, Germany. .,Center for Personalized Translational Epilepsy Research (CePTER), Goethe University, Frankfurt, Germany.
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29
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Epilepsy Syndromes in the First Year of Life and Usefulness of Genetic Testing for Precision Therapy. Genes (Basel) 2021; 12:genes12071051. [PMID: 34356067 PMCID: PMC8307222 DOI: 10.3390/genes12071051] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 06/23/2021] [Accepted: 07/05/2021] [Indexed: 12/18/2022] Open
Abstract
The high pace of gene discovery has resulted in thrilling advances in the field of epilepsy genetics. Clinical testing with comprehensive gene panels, exomes, or genomes are now increasingly available and have led to a significant higher diagnostic yield in early-onset epilepsies and enabled precision medicine approaches. These have been instrumental in providing insights into the pathophysiology of both early-onset benign and self-limited syndromes and devastating developmental and epileptic encephalopathies (DEEs). Genetic heterogeneity is seen in many epilepsy syndromes such as West syndrome and epilepsy of infancy with migrating focal seizures (EIMFS), indicating that two or more genetic loci produce the same or similar phenotypes. At the same time, some genes such as SCN2A can be associated with a wide range of epilepsy syndromes ranging from self-limited familial neonatal epilepsy at the mild end to Ohtahara syndrome, EIFMS, West syndrome, Lennox–Gastaut syndrome, or unclassifiable DEEs at the severe end of the spectrum. The aim of this study was to review the clinical and genetic heterogeneity associated with epilepsy syndromes starting in the first year of life including: Self-limited familial neonatal, neonatal-infantile or infantile epilepsies, genetic epilepsy with febrile seizures plus spectrum, myoclonic epilepsy in infancy, Ohtahara syndrome, early myoclonic encephalopathy, West syndrome, Dravet syndrome, EIMFS, and unclassifiable DEEs. We also elaborate on the advantages and pitfalls of genetic testing in such conditions. Finally, we describe how a genetic diagnosis can potentially enable precision therapy in monogenic epilepsies and emphasize that early genetic testing is a cornerstone for such therapeutic strategies.
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