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Riza AL, Streață I, Roza E, Budișteanu M, Iliescu C, Burloiu C, Dobrescu MA, Dorobanțu S, Dragoș A, Grigorescu A, Tătaru T, Ioana M, Teleanu R. Phenotypic and Genotypic Spectrum of Early-Onset Developmental and Epileptic Encephalopathies-Data from a Romanian Cohort. Genes (Basel) 2022; 13. [PMID: 35886038 DOI: 10.3390/genes13071253] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 07/11/2022] [Accepted: 07/12/2022] [Indexed: 02/01/2023] Open
Abstract
Early-onset developmental epileptic encephalopathy (DEE) refers to an age-specific, diverse group of epilepsy syndromes with electroclinical anomalies that are associated with severe cognitive, behavioral, and developmental impairments. Genetic DEEs have heterogeneous etiologies. This study includes 36 Romanian patients referred to the Regional Centre for Medical Genetics Dolj for genetic testing between 2017 and 2020. The patients had been admitted to and clinically evaluated at Doctor Victor Gomoiu Children’s Hospital and Prof. Dr. Alexandru Obregia Psychiatry Hospital in Bucharest. Panel testing was performed using the Illumina® TruSight™ One “clinical exome” (4811 genes), and the analysis focused on the known genes reported in DEEs and clinical concordance. The overall diagnostic rate was 25% (9/36 cases). Seven cases were diagnosed with Dravet syndrome (likely pathogenic/pathogenic variants in SCN1A) and two with Genetic Epilepsy with Febrile Seizures Plus (SCN1B). For the diagnosed patients, seizure onset was <1 year, and the seizure type was generalized tonic-clonic. Four additional plausible variants of unknown significance in SCN2A, SCN9A, and SLC2A1 correlated with the reported phenotype. Overall, we are reporting seven novel variants. Comprehensive clinical phenotyping is crucial for variant interpretation. Genetic assessment of patients with severe early-onset DEE can be a powerful diagnostic tool for clinicians, with implications for the management and counseling of the patients and their families.
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Inuzuka LM, Macedo-Souza LI, Guerra-Peixe M, Cobas Pedreira C, Della-Ripa B, Souza Delgado D, Monteiro F, Kitajima JP, Garzon E, Kok F. Parental germline mosaicism in SCN3A-related severe developmental disorder. Brain Dev 2021; 43:669-70. [PMID: 33494954 DOI: 10.1016/j.braindev.2020.12.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 12/16/2020] [Accepted: 12/17/2020] [Indexed: 11/23/2022]
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Romantseva L, Lin N. Acute Seizures-Work-Up and Management in Children. Semin Neurol 2020; 40:606-616. [PMID: 33155186 DOI: 10.1055/s-0040-1718718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Seizures are common in the pediatric population; however, most children do not go on to develop epilepsy later in life. Selecting appropriate diagnostic modalities to determine an accurate diagnosis and appropriate treatment as well as with counseling families regarding the etiology and prognosis of seizures, is essential. This article will review updated definitions of seizures, including provoked versus unprovoked, as well as the International League Against Epilepsy operational definition of epilepsy. A variety of specific acute symptomatic seizures requiring special consideration are discussed, along with neonatal seizures and seizure mimics, which are common in pediatric populations.
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Affiliation(s)
- Lubov Romantseva
- Section of Pediatric Neurology, Department of Pediatrics, Rush University Medical Center, Chicago, Illinois
| | - Nan Lin
- Section of Pediatric Neurology, Department of Pediatrics, Rush University Medical Center, Chicago, Illinois
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Noebels JL. Predicting the impact of sodium channel mutations in human brain disease. Epilepsia 2020; 60 Suppl 3:S8-S16. [PMID: 31904123 PMCID: PMC6953257 DOI: 10.1111/epi.14724] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 03/15/2019] [Accepted: 03/18/2019] [Indexed: 12/21/2022]
Abstract
Genetic alteration of the sodium channel provides a remarkable opportunity to understand how epilepsy and its comorbidities arise from a molecular disease of excitable membranes, and a chance to create a better future for children with epileptic encephalopathy. In a single cell, the channel reliably acts as a voltage-sensitive switch, enabling axon impulse firing, whereas at a network level, it becomes a variable rheostat for regulating dynamic patterns of neuronal oscillations, including those underlying cognitive development, seizures, and even premature lethality. Despite steady progress linking genetic variation of the channels with distinctive clinical syndromes, our understanding of the intervening biologic complexity underlying each of them is only just beginning. More research on the functional contribution of individual channel subunits to specific brain networks and cellular plasticity in the developing brain is needed before we can reliably advance from precision diagnosis to precision treatment of inherited sodium channel disorders.
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Affiliation(s)
- Jeffrey L Noebels
- Blue Bird Circle Developmental Neurogenetics Laboratory, Departments of Neurology, Neuroscience, and Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
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de Lange IM, Koudijs MJ, van ‘t Slot R, Sonsma ACM, Mulder F, Carbo EC, van Kempen MJA, Nijman IJ, Ernst RF, Savelberg SMC, Knoers NVAM, Brilstra EH, Koeleman BPC. Assessment of parental mosaicism in SCN1A-related epilepsy by single-molecule molecular inversion probes and next-generation sequencing. J Med Genet 2018; 56:75-80. [DOI: 10.1136/jmedgenet-2018-105672] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 09/24/2018] [Accepted: 09/30/2018] [Indexed: 01/08/2023]
Abstract
BackgroundDravet syndrome is a severe genetic encephalopathy, caused by pathogenic variants in SCN1A. Low-grade parental mosaicism occurs in a substantial proportion of families (7%–13%) and has important implications for recurrence risks. However, parental mosaicism can remain undetected by methods regularly used in diagnostics. In this study, we use single-molecule molecular inversion probes (smMIP), a technique with high sensitivity for detecting low-grade mosaic variants and high cost-effectiveness, to investigate the incidence of parental mosaicism of SCN1A variants in a cohort of 90 families and assess the feasibility of this technique.MethodsDeep sequencing of SCN1A was performed using smMIPs. False positive rates for each of the proband’s pathogenic variants were determined in 145 unrelated samples. If parents showed corresponding variant alleles at a significantly higher rate than the established noise ratio, mosaicism was confirmed by droplet digital PCR (ddPCR).ResultsSequence coverage of at least 100× at the location of the corresponding pathogenic variant was reached for 80 parent couples. The variant ratio was significantly higher than the established noise ratio in eight parent couples, of which four (5%) were regarded as true mosaics, based on ddPCR results. The false positive rate of smMIP analysis without ddPCR was therefore 50%. Three of these variants had previously been considered de novo in the proband by Sanger sequencing.ConclusionsmMIP technology combined withnext generation sequencing (NGS) performs better than Sanger sequencing in the detection of parental mosaicism. Because parental mosaicism has important implications for genetic counselling and recurrence risks, we stress the importance of implementing high-sensitivity NGS-based assays in standard diagnostics.
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de Lange IM, Koudijs MJ, van 't Slot R, Gunning B, Sonsma ACM, van Gemert LJJM, Mulder F, Carbo EC, van Kempen MJA, Verbeek NE, Nijman IJ, Ernst RF, Savelberg SMC, Knoers NVAM, Brilstra EH, Koeleman BPC. Mosaicism of de novo pathogenic SCN1A
variants in epilepsy is a frequent phenomenon that correlates with variable phenotypes. Epilepsia 2018; 59:690-703. [DOI: 10.1111/epi.14021] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/16/2018] [Indexed: 11/28/2022]
Affiliation(s)
- Iris M. de Lange
- Department of Genetics; Center for Molecular Medicine; University Medical Center Utrecht; Utrecht the Netherlands
| | - Marco J. Koudijs
- Department of Genetics; Center for Molecular Medicine; University Medical Center Utrecht; Utrecht the Netherlands
| | - Ruben van 't Slot
- Department of Genetics; Center for Molecular Medicine; University Medical Center Utrecht; Utrecht the Netherlands
| | | | - Anja C. M. Sonsma
- Department of Genetics; Center for Molecular Medicine; University Medical Center Utrecht; Utrecht the Netherlands
| | | | - Flip Mulder
- Department of Genetics; Center for Molecular Medicine; University Medical Center Utrecht; Utrecht the Netherlands
| | - Ellen C. Carbo
- Department of Genetics; Center for Molecular Medicine; University Medical Center Utrecht; Utrecht the Netherlands
| | - Marjan J. A. van Kempen
- Department of Genetics; Center for Molecular Medicine; University Medical Center Utrecht; Utrecht the Netherlands
| | - Nienke E. Verbeek
- Department of Genetics; Center for Molecular Medicine; University Medical Center Utrecht; Utrecht the Netherlands
| | - Isaac J. Nijman
- Department of Genetics; Center for Molecular Medicine; University Medical Center Utrecht; Utrecht the Netherlands
| | - Robert F. Ernst
- Department of Genetics; Center for Molecular Medicine; University Medical Center Utrecht; Utrecht the Netherlands
| | - Sanne M. C. Savelberg
- Department of Genetics; Center for Molecular Medicine; University Medical Center Utrecht; Utrecht the Netherlands
| | - Nine V. A. M. Knoers
- Department of Genetics; Center for Molecular Medicine; University Medical Center Utrecht; Utrecht the Netherlands
| | - Eva H. Brilstra
- Department of Genetics; Center for Molecular Medicine; University Medical Center Utrecht; Utrecht the Netherlands
| | - Bobby P. C. Koeleman
- Department of Genetics; Center for Molecular Medicine; University Medical Center Utrecht; Utrecht the Netherlands
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Dunn P, Albury CL, Maksemous N, Benton MC, Sutherland HG, Smith RA, Haupt LM, Griffiths LR. Next Generation Sequencing Methods for Diagnosis of Epilepsy Syndromes. Front Genet 2018; 9:20. [PMID: 29467791 PMCID: PMC5808353 DOI: 10.3389/fgene.2018.00020] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 01/16/2018] [Indexed: 12/28/2022] Open
Abstract
Epilepsy is a neurological disorder characterized by an increased predisposition for seizures. Although this definition suggests that it is a single disorder, epilepsy encompasses a group of disorders with diverse aetiologies and outcomes. A genetic basis for epilepsy syndromes has been postulated for several decades, with several mutations in specific genes identified that have increased our understanding of the genetic influence on epilepsies. With 70-80% of epilepsy cases identified to have a genetic cause, there are now hundreds of genes identified to be associated with epilepsy syndromes which can be analyzed using next generation sequencing (NGS) techniques such as targeted gene panels, whole exome sequencing (WES) and whole genome sequencing (WGS). For effective use of these methodologies, diagnostic laboratories and clinicians require information on the relevant workflows including analysis and sequencing depth to understand the specific clinical application and diagnostic capabilities of these gene sequencing techniques. As epilepsy is a complex disorder, the differences associated with each technique influence the ability to form a diagnosis along with an accurate detection of the genetic etiology of the disorder. In addition, for diagnostic testing, an important parameter is the cost-effectiveness and the specific diagnostic outcome of each technique. Here, we review these commonly used NGS techniques to determine their suitability for application to epilepsy genetic diagnostic testing.
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Affiliation(s)
- Paul Dunn
- Genomics Research Centre, School of Biomedical Sciences, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, Australia
| | - Cassie L Albury
- Genomics Research Centre, School of Biomedical Sciences, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, Australia
| | - Neven Maksemous
- Genomics Research Centre, School of Biomedical Sciences, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, Australia
| | - Miles C Benton
- Genomics Research Centre, School of Biomedical Sciences, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, Australia
| | - Heidi G Sutherland
- Genomics Research Centre, School of Biomedical Sciences, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, Australia
| | - Robert A Smith
- Genomics Research Centre, School of Biomedical Sciences, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, Australia
| | - Larisa M Haupt
- Genomics Research Centre, School of Biomedical Sciences, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, Australia
| | - Lyn R Griffiths
- Genomics Research Centre, School of Biomedical Sciences, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, Australia
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Ishii A, Watkins JC, Chen D, Hirose S, Hammer MF. Clinical implications of SCN1A missense and truncation variants in a large Japanese cohort with Dravet syndrome. Epilepsia 2016; 58:282-290. [PMID: 28012175 DOI: 10.1111/epi.13639] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/14/2016] [Indexed: 12/28/2022]
Abstract
OBJECTIVE Two major classes of SCN1A variants are associated with Dravet syndrome (DS): those that result in haploinsufficiency (truncating) and those that result in an amino acid substitution (missense). The aim of this retrospective study was to describe the first large cohort of Japanese patients with SCN1A mutation-positive DS (n = 285), and investigate the relationship between variant (type and position) and clinical expression and response to treatment. METHODS We sequenced all exons and intron-exon boundaries of SCN1A in our cohort, investigated differences in the distribution of truncating and missense variants, tested for associations between variant type and phenotype, and compared these patterns with those of cohorts with milder epilepsy and healthy individuals. RESULTS Unlike truncation variants, missense variants are found at higher density in the S4 voltage sensor and pore loops and at lower density in the domain I-II and II-III linkers and the first three segments of domain II. Relative to healthy individuals, there is an increased frequency of truncating (but not missense) variants in the noncoding C-terminus. The rate of cognitive decline is more rapid for patients with truncation variants regardless of age at seizure onset, whereas age at onset is a predictor of the rate of cognitive decline for patients with missense variants. SIGNIFICANCE We found significant differences in the distribution of truncating and missense variants across the SCN1A sequence among healthy individuals, patients with DS, and those with milder forms of SCN1A-variant positive epilepsy. Testing for associations with phenotype revealed that variant type can be predictive of rate of cognitive decline. Analysis of descriptive medication data suggests that in addition to conventional drug therapy in DS, bromide, clonazepam and topiramate may reduce seizure frequency.
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Affiliation(s)
- Atsushi Ishii
- ARL Division of Biotechnology, University of Arizona, Tucson, Arizona, U.S.A.,Department of Pediatrics, School of Medicine and Central Research Institute for the Molecular Pathogeneses of Epilepsy, Fukuoka University, Fukuoka, Japan
| | - Joseph C Watkins
- Department of Mathematics, University of Arizona, Tucson, Arizona, U.S.A
| | - Debbie Chen
- ARL Division of Biotechnology, University of Arizona, Tucson, Arizona, U.S.A
| | - Shinichi Hirose
- Department of Pediatrics, School of Medicine and Central Research Institute for the Molecular Pathogeneses of Epilepsy, Fukuoka University, Fukuoka, Japan
| | - Michael F Hammer
- ARL Division of Biotechnology, University of Arizona, Tucson, Arizona, U.S.A.,Department of Neurology, University of Arizona, Tucson, Arizona, U.S.A
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Xiong Z, Yi L, Cao D, He W, Chen J, Gao S, Sun X. Dravet syndrome with autism inherited from a paternal mosaic heterozygous mutation on SCN1A. J Neurol Sci 2016; 369:53-56. [PMID: 27653866 DOI: 10.1016/j.jns.2016.07.038] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 06/13/2016] [Accepted: 07/14/2016] [Indexed: 11/19/2022]
Affiliation(s)
- Zeyu Xiong
- Key Laboratory for Major Obstetric Diseases of Guangdong Province, The Third Affiliated Hospital, Guangzhou Medical University, Guangdong, People's Republic of China
| | - Li Yi
- School of Life Sciences and Technology, Tongji University, Shanghai, People's Republic of China
| | - Dingya Cao
- Key Laboratory for Major Obstetric Diseases of Guangdong Province, The Third Affiliated Hospital, Guangzhou Medical University, Guangdong, People's Republic of China
| | - Wenteng He
- School of Life Sciences and Technology, Tongji University, Shanghai, People's Republic of China
| | - Jiayu Chen
- Clinical and Translational Research Center of Shanghai First Maternity & Infant Hospital, School of Life Sciences and Technology, Tongji University,1239 Siping Road, Shanghai, 200092, People's Republic of China
| | - Shaorong Gao
- Clinical and Translational Research Center of Shanghai First Maternity & Infant Hospital, School of Life Sciences and Technology, Tongji University,1239 Siping Road, Shanghai, 200092, People's Republic of China.
| | - Xiaofang Sun
- Key Laboratory for Major Obstetric Diseases of Guangdong Province, The Third Affiliated Hospital, Guangzhou Medical University, Guangdong, 510150, People's Republic of China.
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Gao QW, Hua LD, Wang J, Fan CX, Deng WY, Li B, Bian WJ, Shao CX, He N, Zhou P, Liao WP, Shi YW. A Point Mutation in SCN1A 5' Genomic Region Decreases the Promoter Activity and Is Associated with Mild Epilepsy and Seizure Aggravation Induced by Antiepileptic Drug. Mol Neurobiol 2017; 54:2428-34. [PMID: 26969601 DOI: 10.1007/s12035-016-9800-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 02/16/2016] [Indexed: 01/05/2023]
Abstract
The SCN1A gene with 1274 point mutations in the coding regions or genomic rearrangements is the most clinically relevant epilepsy gene. Recent studies have demonstrated that variations in the noncoding regions are potentially associated with epilepsies, but no distinct mutation has been reported. We sequenced the 5' upstream region of SCN1A in 166 patients with epilepsy and febrile seizures who were negative for point mutations in the coding regions or genomic rearrangements. A heterozygous mutation h1u-1962 T > G was identified in a patient with partial epilepsy and febrile seizures, which was aggravated by oxcarbazepine. This mutation was transmitted from the patient's asymptomatic mother and not found in the 110 normal controls. h1u-1962 T > G was located upstream the most frequently used noncoding exon and within the promoter sequences. Further experiments showed that this mutation decreased the promoter activity by 42.1 % compared with that of the paired haplotype (P < 0.001). In contrast to the null expression that results in haploinsufficiency and severe phenotype, this mutation caused relatively less impairment, explaining the mild epilepsy with incomplete penetrance. The antiepileptic drug-induced seizure aggravation in this patient suggests clinical attention for mutations or variations in noncoding regions that may affect SCN1A expression.
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Liu J, Gao C, Chen W, Ma W, Li X, Shi Y, Zhang H, Zhang L, Long Y, Xu H, Guo X, Deng S, Yan X, Yu D, Pan G, Chen Y, Lai L, Liao W, Li Z. CRISPR/Cas9 facilitates investigation of neural circuit disease using human iPSCs: mechanism of epilepsy caused by an SCN1A loss-of-function mutation. Transl Psychiatry 2016; 6:e703. [PMID: 26731440 DOI: 10.1038/tp.2015.203] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Accepted: 11/10/2015] [Indexed: 11/10/2022] Open
Abstract
Mutations in SCN1A, the gene encoding the α subunit of Nav1.1 channel, can cause epilepsies with wide ranges of clinical phenotypes, which are associated with the contrasting effects of channel loss-of-function or gain-of-function. In this project, CRISPR/Cas9- and TALEN-mediated genome-editing techniques were applied to induced pluripotent stem cell (iPSC)-based-disease model to explore the mechanism of epilepsy caused by SCN1A loss-of-function mutation. By fluorescently labeling GABAergic subtype in iPSC-derived neurons using CRISPR/Cas9, we for the first time performed electrophysiological studies on SCN1A-expressing neural subtype and monitored the postsynaptic activity of both inhibitory and excitatory types. We found that the mutation c.A5768G, which led to no current of Nav1.1 in exogenously transfected system, influenced the properties of not only Nav current amount, but also Nav activation in Nav1.1-expressing GABAergic neurons. The two alterations in Nav further reduced the amplitudes and enhanced the thresholds of action potential in patient-derived GABAergic neurons, and led to weakened spontaneous inhibitory postsynaptic currents (sIPSCs) in the patient-derived neuronal network. Although the spontaneous excitatory postsynaptic currents (sEPSCs) did not change significantly, when the frequencies of both sIPSCs and sEPSCs were further analyzed, we found the whole postsynaptic activity transferred from the inhibition-dominated state to excitation in patient-derived neuronal networks, suggesting that changes in sIPSCs alone were sufficient to significantly reverse the excitatory level of spontaneous postsynaptic activity. In summary, our findings fill the gap of our knowledge regarding the relationship between SCN1A mutation effect recorded on exogenously transfected cells and on Nav1.1-expressing neurons, and reveal the physiological basis underlying epileptogenesis caused by SCN1A loss-of-function mutation.
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Xu X, Yang X, Wu Q, Liu A, Yang X, Ye AY, Huang AY, Li J, Wang M, Yu Z, Wang S, Zhang Z, Wu X, Wei L, Zhang Y. Amplicon Resequencing Identified Parental Mosaicism for Approximately 10% of "de novo" SCN1A Mutations in Children with Dravet Syndrome. Hum Mutat 2015; 36:861-72. [PMID: 26096185 PMCID: PMC5034833 DOI: 10.1002/humu.22819] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 05/28/2015] [Indexed: 12/13/2022]
Abstract
The majority of children with Dravet syndrome (DS) are caused by de novo SCN1A mutations. To investigate the origin of the mutations, we developed and applied a new method that combined deep amplicon resequencing with a Bayesian model to detect and quantify allelic fractions with improved sensitivity. Of 174 SCN1A mutations in DS probands which were considered "de novo" by Sanger sequencing, we identified 15 cases (8.6%) of parental mosaicism. We identified another five cases of parental mosaicism that were also detectable by Sanger sequencing. Fraction of mutant alleles in the 20 cases of parental mosaicism ranged from 1.1% to 32.6%. Thirteen (65% of 20) mutations originated paternally and seven (35% of 20) maternally. Twelve (60% of 20) mosaic parents did not have any epileptic symptoms. Their mutant allelic fractions were significantly lower than those in mosaic parents with epileptic symptoms (P = 0.016). We identified mosaicism with varied allelic fractions in blood, saliva, urine, hair follicle, oral epithelium, and semen, demonstrating that postzygotic mutations could affect multiple somatic cells as well as germ cells. Our results suggest that more sensitive tools for detecting low-level mosaicism in parents of families with seemingly "de novo" mutations will allow for better informed genetic counseling.
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Affiliation(s)
- Xiaojing Xu
- Department of PediatricsPeking University First HospitalBeijingChina
| | - Xiaoxu Yang
- Center for BioinformaticsState Key Laboratory of Protein and Plant Gene ResearchSchool of Life SciencesPeking UniversityBeijingChina
| | - Qixi Wu
- National Institute of Biological SciencesBeijingChina
| | - Aijie Liu
- Department of PediatricsPeking University First HospitalBeijingChina
| | - Xiaoling Yang
- Department of PediatricsPeking University First HospitalBeijingChina
| | - Adam Yongxin Ye
- Center for BioinformaticsState Key Laboratory of Protein and Plant Gene ResearchSchool of Life SciencesPeking UniversityBeijingChina
- Peking‐Tsinghua Center for Life SciencesBeijingChina
- Academy for Advanced Interdisciplinary StudiesPeking UniversityBeijingChina
| | | | - Jiarui Li
- Center for BioinformaticsState Key Laboratory of Protein and Plant Gene ResearchSchool of Life SciencesPeking UniversityBeijingChina
| | - Meng Wang
- Center for BioinformaticsState Key Laboratory of Protein and Plant Gene ResearchSchool of Life SciencesPeking UniversityBeijingChina
| | - Zhe Yu
- National Institute of Biological SciencesBeijingChina
| | - Sheng Wang
- National Institute of Biological SciencesBeijingChina
- College of Biological SciencesChina Agricultural UniversityBeijingChina
| | - Zhichao Zhang
- Andrology CenterPeking University First HospitalBeijingChina
| | - Xiru Wu
- Department of PediatricsPeking University First HospitalBeijingChina
| | - Liping Wei
- Center for BioinformaticsState Key Laboratory of Protein and Plant Gene ResearchSchool of Life SciencesPeking UniversityBeijingChina
- National Institute of Biological SciencesBeijingChina
| | - Yuehua Zhang
- Department of PediatricsPeking University First HospitalBeijingChina
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Tuncer FN, Gormez Z, Calik M, Altiokka Uzun G, Sagiroglu MS, Yuceturk B, Yuksel B, Baykan B, Bebek N, Iscan A, Ugur Iseri SA, Ozbek U. A clinical variant in SCN1A inherited from a mosaic father cosegregates with a novel variant to cause Dravet syndrome in a consanguineous family. Epilepsy Res 2015; 113:5-10. [DOI: 10.1016/j.eplepsyres.2015.02.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 02/12/2015] [Accepted: 02/27/2015] [Indexed: 11/26/2022]
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14
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Guala A, Peruzzi C, Gennaro E, Pennese L, Danesino C. Maternal germinal mosaicism forSCN1Ain sibs with a mild form of Dravet syndrome. Am J Med Genet A 2015; 167A:1165-7. [DOI: 10.1002/ajmg.a.36990] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 01/04/2015] [Indexed: 11/06/2022]
Affiliation(s)
- Andrea Guala
- SOC Pediatria; Ospedale Castelli; Verbania Italy
| | | | - Elena Gennaro
- Laboratorio di Genetica Umana; E.O. Ospedali Galliera; Genova Italy
| | - Loredana Pennese
- Laboratorio di Genetica Umana; E.O. Ospedali Galliera; Genova Italy
| | - Cesare Danesino
- Dipartimento di Medicina Molecolare; University of Pavia, and IRCCS S. Matteo; Pavia Italy
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Meng H, Xu HQ, Yu L, Lin GW, He N, Su T, Shi YW, Li B, Wang J, Liu XR, Tang B, Long YS, Yi YH, Liao WP. TheSCN1AMutation Database: Updating Information and Analysis of the Relationships among Genotype, Functional Alteration, and Phenotype. Hum Mutat 2015; 36:573-80. [PMID: 25754450 DOI: 10.1002/humu.22782] [Citation(s) in RCA: 136] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 02/25/2015] [Indexed: 11/11/2022]
Affiliation(s)
- Heng Meng
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University; Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
- Department of Neurology; The First Affiliated Hospital of Jinan University; Guangzhou China
| | - Hai-Qing Xu
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University; Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
| | - Lu Yu
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University; Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
| | - Guo-Wang Lin
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University; Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
| | - Na He
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University; Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
| | - Tao Su
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University; Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
| | - Yi-Wu Shi
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University; Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
| | - Bin Li
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University; Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
| | - Jie Wang
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University; Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
| | - Xiao-Rong Liu
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University; Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
| | - Bin Tang
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University; Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
| | - Yue-Sheng Long
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University; Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
| | - Yong-Hong Yi
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University; Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
| | - Wei-Ping Liao
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University; Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
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16
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Abstract
PURPOSE OF REVIEW There is a long-standing hypothesis that febrile status epilepticus (FSE) can cause brain injury, particularly to the hippocampus. This review will evaluate recent evidence on the relationships between FSE and later epilepsy and cognitive impairments. Potential strategies for minimizing adverse outcomes will be discussed. RECENT FINDINGS There are two major longitudinal studies evaluating the outcomes for FSE. These studies provide evidence of acute hippocampal edema that evolves to mesial temporal sclerosis in a small number of children (∼7%). However, none of these children have developed temporal lobe epilepsy. There is also evidence of more global white matter injury. Development is affected, with a loss of about 10 developmental quotient points and there is evidence for accelerated forgetting. These findings do not correlate with MRI parameters. Therefore, FSE can cause a wide spectrum of injury, but the relationship between this and clinically relevant adverse outcomes remains uncertain. SUMMARY Although there is accumulating evidence that FSE can cause brain injury, the strategies to minimize the impact remain uncertain. Imaging requires sedation, with inherent risks, and may not be appropriate for all children with FSE, given the small number with significant hippocampal edema that could be a biomarker. The alternative of treating all children requires a very safe drug which currently does not exist.
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Abstract
Genetic mechanisms explain the pathophysiology of many forms of epilepsy and other paroxysmal disorders, such as alternating hemiplegia of childhood, familial hemiplegic migraine, and paroxysmal dyskinesias. Epilepsy is a key feature of well-defined genetic syndromes including tuberous sclerosis complex, Rett syndrome, Angelman syndrome, and others. There is an increasing number of single-gene causes or susceptibility factors associated with several epilepsy syndromes, including the early-onset epileptic encephalopathies, benign neonatal/infantile seizures, progressive myoclonus epilepsies, genetic generalized and benign focal epilepsies, epileptic aphasias, and familial focal epilepsies. Molecular mechanisms are diverse, and a single gene can be associated with a broad range of phenotypes. Additional features, such as dysmorphisms, head size, movement disorders, and family history may provide clues to a genetic diagnosis. Genetic testing can impact medical care and counseling. We discuss genetic mechanisms of epilepsy and other paroxysmal disorders, tools and indications for genetic testing, known genotype-phenotype associations, the importance of genetic counseling, and a look toward the future of epilepsy genetics.
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Affiliation(s)
- Heather E Olson
- Division of Epilepsy, Department of Neurology, Boston Children's Hospital, Boston, Massachusetts
| | - Annapurna Poduri
- Division of Epilepsy, Department of Neurology, Boston Children's Hospital, Boston, Massachusetts
| | - Phillip L Pearl
- Division of Epilepsy, Department of Neurology, Boston Children's Hospital, Boston, Massachusetts
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18
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Gómez-Ramos A, Sanchez-Sanchez R, Muhaisen A, Rábano A, Soriano E, Avila J. Similarities and differences between exome sequences found in a variety of tissues from the same individual. PLoS One 2014; 9:e101412. [PMID: 24984015 DOI: 10.1371/journal.pone.0101412] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 06/06/2014] [Indexed: 12/30/2022] Open
Abstract
DNA is the most stable nucleic acid and most important store of genetic information. DNA sequences are conserved in virtually all the cells of a multicellular organism. To analyze the sequences of various individuals with distinct pathological disorders, DNA is routinely isolated from blood, independently of the tissue that is the target of the disease. This approach has proven useful for the identification of familial diseases where mutations are present in parental germinal cells. With the capacity to compare DNA sequences from distinct tissues or cells, present technology can be used to study whether DNA sequences in tissues are invariant. Here we explored the presence of specific SNVs (Single Nucleotide Variations) in various tissues of the same individual. We tested for the presence of tissue-specific exonic SNVs, taking blood exome as a control. We analyzed the chromosomal location of these SNVs. The number of SNVs per chromosome was found not to depend on chromosome length, but mainly on the number of protein-coding genes per chromosome. Although similar but not identical patterns of chromosomal distribution of tissue-specific SNVs were found, clear differences were detected. This observation supports the notion that each tissue has a specific SNV exome signature.
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19
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Wang Z, Fan Y, Xu J, Li L, Heng D, Han S, Yin J, Peng B, Liu W, He X. Transcriptome analysis of the hippocampus in novel rat model of febrile seizures. PLoS One 2014; 9:e95237. [PMID: 24736375 PMCID: PMC3988142 DOI: 10.1371/journal.pone.0095237] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Accepted: 03/24/2014] [Indexed: 01/12/2023] Open
Abstract
Febrile seizures (FS) are the most common type of convulsive events in infants and young children, but the precise underlying genetic mechanism remains to be explored. To investigate the underlying pathogenic factors in FS and subsequent epilepsy, alterations in gene expression between the two new strains of rats (hyperthermia-prone [HP] vs hyperthermia-resistant [HR]), were investigated by using the Whole Rat Genome Oligo Microarray. This process identified 1,140 differentially expressed genes (DEGs; 602 upregulated and 538 downregulated), which were analyzed to determine significant Gene Ontology (GO) categories, signaling pathways and gene networks. Based on the GO analyses, the modified genes are closely related to various FS pathogenesis factors, including immune and inflammatory responses and ion transport. Certain DEGs identified have not been previously examined in relation to FS pathogenesis. Among these genes is dipeptidyl peptidase 4 (DPP4), a gene closely linked to interleukin 6 (IL-6), which played a key role in the gene network analysis. Furthermore, sitagliptin, a DPP4 inhibitor significantly decreased epileptic discharge in rats, observed via electroencephalogram, suggesting an important role for DPP4 in FS. The effectiveness of sitagliptin in reducing seizure activity may occur through a mechanism that stabilizes cellular Ca2+ homeostasis. In addition, DPP4 expression may be regulated by DNA methylation. The hippocampal gene expression profiles in novel rat models of FS provides a large database of candidate genes and pathways, which will be useful for researchers interested in disorders of neuronal excitability.
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Affiliation(s)
- Zhongcheng Wang
- Department of Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Yuanteng Fan
- Department of Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Jian Xu
- Department of Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Liang Li
- Department of Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Duanhe Heng
- Department of Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Song Han
- Department of Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Jun Yin
- Department of Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Biwen Peng
- Hubei Provincial Key Laboratory of Developmentally Originated Disease, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Wanhong Liu
- Hubei Province Key Laboratory of Allergy and Immunology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
- * E-mail: (WL); (XH)
| | - Xiaohua He
- Department of Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
- * E-mail: (WL); (XH)
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20
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Tavassoli T, Kolevzon A, Wang AT, Curchack-Lichtin J, Halpern D, Schwartz L, Soffes S, Bush L, Grodberg D, Cai G, Buxbaum JD. De novo SCN2A splice site mutation in a boy with Autism spectrum disorder. BMC Med Genet 2014; 15:35. [PMID: 24650168 PMCID: PMC3994485 DOI: 10.1186/1471-2350-15-35] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Accepted: 03/11/2014] [Indexed: 01/09/2023]
Abstract
BACKGROUND SCN2A is a gene that codes for the alpha subunit of voltage-gated, type II sodium channels, and is highly expressed in the brain. Sodium channel disruptions, such as mutations in SCN2A, may play an important role in psychiatric disorders. Recently, de novo SCN2A mutations in autism spectrum disorder (ASD) have been identified. The current study characterizes a de novo splice site mutation in SCN2A that alters mRNA and protein products. CASE PRESENTATION We describe results from clinical and genetic characterizations of a seven-year-old boy with ASD. Psychiatric interview and gold standard autism diagnostic instruments (ADOS and ADI-R) were used to confirm ASD diagnosis, in addition to performing standardized cognitive and adaptive functioning assessments (Leiter-R and Vineland Adaptive Behavior Scale), and sensory reactivity assessments (Sensory Profile and Sensory Processing Scales). Genetic testing by whole exome sequencing revealed four de novo events, including a splice site mutation c.476 + 1G > A in SCN2A, a missense mutation (c.2263G > A) causing a p.V755I change in the TLE1 gene, and two synonymous mutations (c.2943A > G in the BUB1 gene, and c.1254 T > A in C10orf68 gene). The de novo SCN2A splice site mutation produced a stop codon 10 amino acids downstream, possibly resulting in a truncated protein and/or a nonsense-mediated mRNA decay. The participant met new DSM-5 criteria for ASD, presenting with social and communication impairment, repetitive behaviors, and sensory reactivity issues. The participant's adaptive and cognitive skills fell in the low range of functioning. CONCLUSION This report indicates that a splice site mutation in SCN2A might be contributing to the risk of ASD. Describing the specific phenotype associated with SCN2A mutations might help to reduce heterogeneity seen in ASD.
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Affiliation(s)
- Teresa Tavassoli
- Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
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21
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Abstract
Genetic factors are likely to play a major role in many epileptic conditions, spanning from classical idiopathic (genetic) generalized epilepsies to epileptic encephalopathies and focal epilepsies. In this review we describe the genetic advances in progressive myoclonus epilepsies, which are strictly monogenic disorders, genetic generalized epilepsies, mostly exhibiting complex genetic inheritance, and SCN1A-related phenotypes, namely genetic generalized epilepsy with febrile seizure plus and Dravet syndrome. Particular attention is devoted to a form of familial focal epilepsies, autosomal-dominant lateral temporal epilepsy, which is a model of non-ion genetic epilepsies. This condition is associated with mutations of the LGI1 gene, whose protein is secreted from the neurons and exerts its action on a number of targets, influencing cortical development and neuronal maturation.
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Affiliation(s)
- Roberto Michelucci
- Unit of Neurology, IRCCS Institute of Neurological Sciences, Bellaria Hospital, Via Altura 3, 40139, Bologna, Italy.
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