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Xiao T, Chen X, Xu Y, Chen H, Dong X, Yang L, Wu B, Chen L, Li L, Zhuang D, Chen D, Zhou Y, Wang H, Zhou W. Clinical Study of 30 Novel KCNQ2 Variants/Deletions in KCNQ2-Related Disorders. Front Mol Neurosci 2022; 15:809810. [PMID: 35557555 PMCID: PMC9088225 DOI: 10.3389/fnmol.2022.809810] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 03/02/2022] [Indexed: 11/24/2022] Open
Abstract
Background KCNQ2-related disorder is typically characterized as neonatal onset seizure and epileptic encephalopathy. The relationship between its phenotype and genotype is still elusive. This study aims to provide clinical features, management, and prognosis of patients with novel candidate variants of the KCNQ2 gene. Methods We enrolled patients with novel variants in the KCNQ2 gene from the China Neonatal Genomes Project between January 2018 and January 2021. All patients underwent next-generation sequencing tests and genetic data were analyzed by an in-house pipeline. The pathogenicity of variants was classified according to the guideline of the American College of Medical Genetics. Each case was evaluated by two geneticists back to back. Patients' information was acquired from clinical records. Results A total of 30 unrelated patients with novel variants in the KCNQ2 gene were identified, including 19 patients with single-nucleotide variants (SNVs) and 11 patients with copy number variants (CNVs). For the 19 SNVs, 12 missense variants and 7 truncating variants were identified. Of them, 36.8% (7/19) of the KCNQ2 variants were located in C-terminal regions, 15.7% (3/19) in segment S2, and 15.7% (3/19) in segment S4. Among them, 18 of 19 patients experienced seizures in the early neonatal period. However, one patient presented neurodevelopmental delay (NDD) as initial phenotype when he was 2 months old, and he had severe NDD when he was 3 years old. This patient did not present seizure but had abnormal electrographic background activity and brain imaging. Moreover, for the 11 patients with CNVs, 20q13.3 deletions involving EEF1A2, KCNQ2, and CHRNA4 genes were detected. All of them presented neonatal-onset seizures, responded to antiepileptic drugs, and had normal neurological development. Conclusion In this study, patients with novel KCNQ2 variants have variable phenotypes, whereas patients with 20q13.3 deletion involving EEF1A2, KCNQ2, and CHRNA4 genes tend to have normal neurological development.
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Affiliation(s)
- Tiantian Xiao
- Department of Neonatology, National Children's Medical Center, Children's Hospital of Fudan University, Shanghai, China
| | - Xiang Chen
- Department of Neonatology, National Children's Medical Center, Children's Hospital of Fudan University, Shanghai, China
| | - Yan Xu
- Division of Neurology, National Children's Medical Center, Children's Hospital of Fudan University, Shanghai, China
| | - Huiyao Chen
- Center for Molecular Medicine, National Children's Medical Center, Children's Hospital of Fudan University, Shanghai, China
| | - Xinran Dong
- Center for Molecular Medicine, National Children's Medical Center, Children's Hospital of Fudan University, Shanghai, China
| | - Lin Yang
- Department of Endocrinology and Inherited Metabolic Diseases, National Children's Medical Center, Children's Hospital of Fudan University, Shanghai, China
| | - Bingbing Wu
- Center for Molecular Medicine, National Children's Medical Center, Children's Hospital of Fudan University, Shanghai, China
| | - Liping Chen
- Jiangxi Provincial Children's Hospital, Nanchang, China
| | - Long Li
- Department of Neonatology, People's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, China
| | | | - Dongmei Chen
- Quanzhou Women and Children's Hospital, Quanzhou, China
| | - Yuanfeng Zhou
- Division of Neurology, National Children's Medical Center, Children's Hospital of Fudan University, Shanghai, China
- *Correspondence: Yuanfeng Zhou
| | - Huijun Wang
- Center for Molecular Medicine, National Children's Medical Center, Children's Hospital of Fudan University, Shanghai, China
- Huijun Wang
| | - Wenhao Zhou
- Department of Neonatology, National Children's Medical Center, Children's Hospital of Fudan University, Shanghai, China
- Center for Molecular Medicine, National Children's Medical Center, Children's Hospital of Fudan University, Shanghai, China
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Nikitin ES, Vinogradova LV. Potassium channels as prominent targets and tools for the treatment of epilepsy. Expert Opin Ther Targets 2021; 25:223-235. [PMID: 33754930 DOI: 10.1080/14728222.2021.1908263] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
INTRODUCTION K+ channels are of great interest to epilepsy research as mutations in their genes are found in humans with inherited epilepsy. At the level of cellular physiology, K+ channels control neuronal intrinsic excitability and are the main contributors to membrane repolarization of active neurons. Recently, a genetically modified voltage-dependent K+ channel has been patented as a remedy for epileptic seizures. AREAS COVERED We review the role of potassium channels in excitability, clinical and experimental evidence for the association of potassium channelopathies with epilepsy, the targeting of K+ channels by drugs, and perspectives of gene therapy in epilepsy with the expression of extra K+ channels in the brain. EXPERT OPINION Control over K+ conductance is of great potential benefit for the treatment of epilepsy. Nowadays, gene therapy affecting K+ channels is one of the most promising approaches to treat pharmacoresistant focal epilepsy.
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Affiliation(s)
- E S Nikitin
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
| | - L V Vinogradova
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
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Targeted gene panel sequencing in early infantile onset developmental and epileptic encephalopathy. Brain Dev 2020; 42:438-448. [PMID: 32139178 DOI: 10.1016/j.braindev.2020.02.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 02/13/2020] [Accepted: 02/16/2020] [Indexed: 01/06/2023]
Abstract
BACKGROUND Early-onset developmental and epileptic encephalopathy (DEE) is characterized by repeated seizures beginning within 3 months of birth and severe interictal epileptiform discharge, including burst suppression. This study assessed the utility of targeted gene panel sequencing in the genetic diagnosis of this disease. MATERIALS AND METHODS Targeted gene panel sequencing was performed in 150 early infantile-onset DEE patients (≤3 months of age), and we extensively reviewed their clinical characteristics, including therapeutic efficacy, according to genotype. RESULTS Of the early infantile-onset DEE patients, 70 were neonatal-onset DEE and the other 80 patients began experiencing seizures from 1 to 3 months after birth. There were 11 different pathogenic or likely pathogenic variants among 34.7% (52/150) of patients with early infantile-onset DEE, in whom KCNQ2, STXBP1, CDKL5, and SCN1A were the major pathogenic variants. Among the neonatal-onset DEE patients, pathological genes were identified in 42.9% (30/70), indicating a significantly higher diagnostic yield than in 27.5% (22/80) of patients who experienced seizure onset 1 to 3 months after birth (p = 0.048). Among the neonatal-onset DEE group, variants in KCNQ2, STXBP1, and CDKL5 were detected at high frequencies, accounting for 66.7% (20/30) of the pathogenic or likely pathogenic variants found in this study. CONCLUSION Targeted gene panel sequencing demonstrated a high yield of pathogenic variants in the diagnosis of early-onset epileptic encephalopathy, especially in those with neonatal-onset DEE. Early diagnosis of early-onset epileptic encephalopathy may improve the prognosis of patients by earlier selection of appropriate treatment based on pathogenic variant.
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Lee IC, Chang TM, Liang JS, Li SY. KCNQ2 mutations in childhood nonlesional epilepsy: Variable phenotypes and a novel mutation in a case series. Mol Genet Genomic Med 2019; 7:e00816. [PMID: 31199083 PMCID: PMC6625149 DOI: 10.1002/mgg3.816] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 03/25/2019] [Accepted: 05/29/2019] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Epilepsy caused by a KCNQ2 gene mutation usually manifests as neonatal seizures during the first week of life. The genotypes and phenotypes of KCNQ2 mutations are noteworthy. METHODS The KCNQ2 sequencings done were selected from 131 nonconsanguineous pediatric epileptic patients (age range: 2 days to 18 years) with nonlesional epilepsy. RESULTS Seven (5%) index patients had verified KCNQ2 mutations: c.387+1 G>T (splicing), c.1741 C>T (p.Arg581*), c.740 C>T p.(Ser247Leu), c.853 C>A p.(Pro285Thr), c.860 C>T p.(Thr287Ile), c.1294 C>T p.(Arg432Cys), and c.1627 G>A p.(Val543Met). We found, after their paternity had been confirmed, that three patients had de novo p.(Ser247Leu), p.(Pro285Thr), and p.(Thr287Ile) mutations and neonatal-onset epileptic encephalopathy; however, their frequent seizures remitted after they turned 6 months old. Those with the c.387+1G>T (splicing), (p.Arg581*), and p.(Val543Met) mutations presented with benign familial neonatal convulsions. In addition to their relatives, 14 patients had documented KCNQ2 mutations, and 12 (86%) had neonatal seizures. The seizures of all five patients treated with oxcarbazepine remitted. CONCLUSION KCNQ2-related epilepsy led to varied outcomes (from benign to severe) in our patients. KCNQ2 mutations accounted for 13% of patients with seizure onset before 2 months old in our study. KCNQ2 mutations can cause different phenotypes in children. p.(Pro 285Thr) is a novel mutation, and the p.(Pro 285Thr), p.(Ser247Leu), and p.(Thr287Ile) variants can cause neonatal-onset epileptic encephalopathy.
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Affiliation(s)
- Inn-Chi Lee
- Division of Pediatric Neurology, Department of Pediatrics, Chung Shan Medical University Hospital, Taichung, Taiwan.,Institute of Medicine, School of Medicine, Chung Shan Medical University, Taichung, Taiwan
| | - Tung-Ming Chang
- Department of Pediatric Neurology, Changhua Christian Children's Hospital, Changhua, Taiwan.,Graduate Institute of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Jao-Shwann Liang
- Department of Pediatrics, Far Eastern Memorial Hospital, New Taipei City, Taiwan
| | - Shuan-Yow Li
- Institute of Medicine, School of Medicine, Chung Shan Medical University, Taichung, Taiwan.,Genetics Laboratory and Department of Biomedical Sciences, Chung Shan Medical University, Taichung, Taiwan
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Laccetta G, Fiori S, Giampietri M, Ferrari A, Cetica V, Bernardini M, Chesi F, Mazzotti S, Parrini E, Ciantelli M, Guzzetta A, Ghirri P. A de novo KCNQ2 Gene Mutation Associated With Non-familial Early Onset Seizures: Case Report and Revision of Literature Data. Front Pediatr 2019; 7:348. [PMID: 31552204 PMCID: PMC6743415 DOI: 10.3389/fped.2019.00348] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 08/05/2019] [Indexed: 12/20/2022] Open
Abstract
Among neonatal epileptic syndromes, benign familial neonatal seizures (BFNS) are often due to autosomal-dominant mutations of the KCNQ2 gene. Seizures are usually characterized by asymmetric tonic posturing with apnea with onset in the first 7 days of life; they may even occur more than 10 times per day or evolve into status epilepticus. The delivery course of our patient was uneventful and family history was negative; on the second day of life the baby became pale, rigid, and apnoic during breastfeeding and appeared jittery and irritable when stimulated or examined. At age 3 days, she experienced clusters of generalized tonic seizures with pallor, desaturation, bradycardia, and partial response to intravenous phenobarbital; during her 4th and 5th days of life, three episodes of tonic seizures were noticed. At age 6 days, the patient experienced about 10 episodes of tonic seizures involving both sides of the body, which gradually responded to intravenous phenytoin. Electroencephalograms revealed abnormalities but brain MRI was normal. The patient is seizure-free since postnatal day 21; she is now 12 months old with cognitive development within normal limits at Bayley III Scale and mild motor delay. The patient is on maintenance therapy with phenobarbital since she was 7 months old. A de novo heterozygous mutation (c.853C>T/p.P285S) in the KCNQ2 gene was identified. We therefore describe a case of de novo KCNQ2-related neonatal convulsions with necessity of multiple anticonvulsants for the control of seizures, mutation occurring in the pore channel of the voltage-gated potassium channel subfamily Q member 2 associated with a likely benign course; furthermore, the same mutation of the KCNQ2 gene and a similar one (c.854C>A/p.P285H) have already been described in association with Ohtahara syndrome. Probably acquired environmental, perinatal and genetic risk factors are very important in determining the different phenotype; we hope that the rapid progress of analysis tools in molecular diagnosis can also be used in the search of an individualized therapeutic approach for these patients.
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Affiliation(s)
- Gianluigi Laccetta
- Division of Neonatology and Neonatal Intensive Care Unit, Department of Maternal and Child Health, Santa Chiara Hospital, University of Pisa, Pisa, Italy
| | - Simona Fiori
- Department of Developmental Neuroscience, IRCCS Stella Maris, Pisa, Italy
| | - Matteo Giampietri
- Division of Neonatology and Neonatal Intensive Care Unit, Department of Maternal and Child Health, Santa Chiara Hospital, University of Pisa, Pisa, Italy
| | - Annarita Ferrari
- Department of Developmental Neuroscience, IRCCS Stella Maris, Pisa, Italy
| | - Valentina Cetica
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Neuroscience Department, Meyer Children's University Hospital, University of Florence, Florence, Italy
| | - Manuela Bernardini
- Division of Neonatology and Neonatal Intensive Care Unit, Department of Maternal and Child Health, Santa Chiara Hospital, University of Pisa, Pisa, Italy
| | - Francesca Chesi
- Division of Neonatology and Neonatal Intensive Care Unit, Department of Maternal and Child Health, Santa Chiara Hospital, University of Pisa, Pisa, Italy
| | - Sara Mazzotti
- Department of Developmental Neuroscience, IRCCS Stella Maris, Pisa, Italy
| | - Elena Parrini
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Neuroscience Department, Meyer Children's University Hospital, University of Florence, Florence, Italy
| | - Massimiliano Ciantelli
- Division of Neonatology and Neonatal Intensive Care Unit, Department of Maternal and Child Health, Santa Chiara Hospital, University of Pisa, Pisa, Italy
| | - Andrea Guzzetta
- Department of Developmental Neuroscience, IRCCS Stella Maris, Pisa, Italy.,Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Paolo Ghirri
- Division of Neonatology and Neonatal Intensive Care Unit, Department of Maternal and Child Health, Santa Chiara Hospital, University of Pisa, Pisa, Italy
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