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Falace A, Volpedo G, Scala M, Zara F, Striano P, Fassio A. V-ATPase Dysfunction in the Brain: Genetic Insights and Therapeutic Opportunities. Cells 2024; 13:1441. [PMID: 39273013 PMCID: PMC11393946 DOI: 10.3390/cells13171441] [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: 07/06/2024] [Revised: 08/23/2024] [Accepted: 08/25/2024] [Indexed: 09/15/2024] Open
Abstract
Vacuolar-type ATPase (v-ATPase) is a multimeric protein complex that regulates H+ transport across membranes and intra-cellular organelle acidification. Catabolic processes, such as endocytic degradation and autophagy, strictly rely on v-ATPase-dependent luminal acidification in lysosomes. The v-ATPase complex is expressed at high levels in the brain and its impairment triggers neuronal dysfunction and neurodegeneration. Due to their post-mitotic nature and highly specialized function and morphology, neurons display a unique vulnerability to lysosomal dyshomeostasis. Alterations in genes encoding subunits composing v-ATPase or v-ATPase-related proteins impair brain development and synaptic function in animal models and underlie genetic diseases in humans, such as encephalopathies, epilepsy, as well as neurodevelopmental, and degenerative disorders. This review presents the genetic and functional evidence linking v-ATPase subunits and accessory proteins to various brain disorders, from early-onset developmental epileptic encephalopathy to neurodegenerative diseases. We highlight the latest emerging therapeutic strategies aimed at mitigating lysosomal defects associated with v-ATPase dysfunction.
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Affiliation(s)
- Antonio Falace
- Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto Giannina Gaslini, 16147 Genoa, Italy
| | - Greta Volpedo
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, 16132 Genoa, Italy
| | - Marcello Scala
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, 16132 Genoa, Italy
- Medical Genetics Unit, IRCCS Istituto Giannina Gaslini, 16147 Genoa, Italy
| | - Federico Zara
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, 16132 Genoa, Italy
- Medical Genetics Unit, IRCCS Istituto Giannina Gaslini, 16147 Genoa, Italy
| | - Pasquale Striano
- Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto Giannina Gaslini, 16147 Genoa, Italy
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, 16132 Genoa, Italy
| | - Anna Fassio
- Department of Experimental Medicine, University of Genoa, 16132 Genoa, Italy
- IRCCS, Ospedale Policlinico San Martino, 16132 Genoa, Italy
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Lei P, Zhu Q, Dong W. Investigation of a novel TBC1D24 variation causing autosomal dominant non-syndromic hearing loss. Sci Rep 2024; 14:4734. [PMID: 38413761 PMCID: PMC10899226 DOI: 10.1038/s41598-024-55435-5] [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: 09/05/2023] [Accepted: 02/23/2024] [Indexed: 02/29/2024] Open
Abstract
Hearing loss is considered one of the most common sensory neurological defects, with approximately 60% of cases attributed to genetic factors. Human pathogenic variants in the TBC1D24 gene are associated with various clinical phenotypes, including dominant nonsyndromic hearing loss DFNA65, characterized by progressive hearing loss after the development of language. This study provides an in-depth analysis of the causative gene and mutations in a family with hereditary deafness. We recruited a three-generation family with autosomal dominant nonsyndromic hearing loss (ADNSHL) and conducted detailed medical histories and relevant examinations. Next-generation sequencing (NGS) was used to identify genetic variants in the proband, which were then validated using Sanger sequencing. Multiple computational software tools were employed to predict the impact of the variant on the function and structure of the TBC1D24 protein. A series of bioinformatics tools were applied to determine the conservation characteristics of the sequence, establish a three-dimensional structural model, and investigate changes in molecular dynamics. A detailed genotype and phenotype analysis were carried out. The family exhibited autosomal dominant, progressive, postlingual, and nonsyndromic sensorineural hearing loss. A novel heterozygous variant, c.1459C>T (p.His487Tyr), in the TBC1D24 gene was identified and confirmed to be associated with the hearing loss phenotype in this family. Conservation analysis revealed high conservation of the amino acid affected by this variant across different species. The mutant protein showed alterations in thermodynamic stability, elasticity, and conformational dynamics. Molecular dynamics simulations indicated changes in RMSD, RMSF, Rg, and SASA of the mutant structure. We computed the onset age of non-syndromic hearing loss associated with mutations in the TBC1D24 gene and identified variations in the hearing progression time and annual threshold deterioration across different frequencies. The identification of a new variant associated with rare autosomal dominant nonsyndromic hereditary hearing loss in this family broadens the range of mutations in the TBC1D24 gene. This variant has the potential to influence the interaction between the TLDc domain and TBC domain, thereby affecting the protein's biological function.
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Affiliation(s)
- Peiliang Lei
- Department of Otolaryngology Head & Neck Surgery, The Second Hospital of Hebei Medical University, Heping West Road No. 215, Shijiazhuang, 050000, Hebei, China
- Department of Otolaryngology Head & Neck Surgery, The Third Hospital of Shijiazhuang, Tiyu South Street No.15, Shijiazhuang, 050011, Hebei, China
| | - Qingwen Zhu
- Department of Otolaryngology Head & Neck Surgery, The Second Hospital of Hebei Medical University, Heping West Road No. 215, Shijiazhuang, 050000, Hebei, China.
| | - Wenrong Dong
- Department of Otolaryngology Head & Neck Surgery, The Third Hospital of Shijiazhuang, Tiyu South Street No.15, Shijiazhuang, 050011, Hebei, China
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Bagnall RD, Perucca P. ILAE Genetic Literacy Series: Postmortem Genetic Testing in Sudden Unexpected Death in Epilepsy. Epileptic Disord 2023; 25:472-479. [PMID: 37340991 DOI: 10.1002/epd2.20090] [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: 03/15/2023] [Revised: 05/31/2023] [Accepted: 06/17/2023] [Indexed: 06/22/2023]
Abstract
A 24-year-old man with non-lesional bitemporal lobe epilepsy since age 16 years was found dead in bed around midday. He was last seen the previous night when he was witnessed to have a tonic-clonic seizure. Before his death, he was experiencing weekly focal impaired awareness seizures and up to two focal-to-bilateral tonic-clonic seizures each year. He had trialed several antiseizure medications and was on levetiracetam 1500 mg/day, lamotrigine 400 mg/day, and clobazam 10 mg/day at the time of death. Other than epilepsy, his medical history was unremarkable. Of note, he had an older brother with a history of febrile seizures and a paternal first cousin with epilepsy. No cause of death was identified following a comprehensive postmortem investigation. The coroner classified the death as "sudden unexpected death in epilepsy" (SUDEP), and it would qualify as "definite SUDEP" using the current definitions.1 This left the family with many questions unanswered; in particular, they wish to know what caused the death and whether it could happen to other family members. Could postmortem genetic testing identify a cause of death, provide closure to the family, and facilitate cascade genetic testing of first-degree family members who may be at risk of sudden death? While grieving family members struggle with uncertainty about the cause of death, we as clinicians also face similar uncertainties about genetic contributions to SUDEP, especially when the literature is sparse, and the utility of genetic testing is still being worked out. We aim to shed some light on this topic, highlighting areas where data is emerging but also areas where uncertainty remains, keeping our case in mind as we examine this clinically important area.
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Affiliation(s)
- Richard D Bagnall
- Agnes Ginges Centre for Molecular Cardiology at Centenary Institute, University of Sydney, Sydney, New South Wales, Australia
- Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia
| | - Piero Perucca
- Department of Medicine (Austin Health), Epilepsy Research Centre, The University of Melbourne, Melbourne, Victoria, Australia
- Bladin-Berkovic Comprehensive Epilepsy Program, Department of Neurology, Austin Health, Melbourne, Victoria, Australia
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Victoria, Australia
- Department of Neurology, Alfred Health, Melbourne, Victoria, Australia
- Department of Neurology, The Royal Melbourne Hospital, Melbourne, Victoria, Australia
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Spagnoli C, Fusco C, Pisani F. Pediatric-Onset Epilepsy and Developmental Epileptic Encephalopathies Followed by Early-Onset Parkinsonism. Int J Mol Sci 2023; 24:ijms24043796. [PMID: 36835207 PMCID: PMC9965035 DOI: 10.3390/ijms24043796] [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: 01/10/2023] [Revised: 02/09/2023] [Accepted: 02/10/2023] [Indexed: 02/16/2023] Open
Abstract
Genetic early-onset Parkinsonism is unique due to frequent co-occurrence of hyperkinetic movement disorder(s) (MD), or additional neurological of systemic findings, including epilepsy in up to 10-15% of cases. Based on both the classification of Parkinsonism in children proposed by Leuzzi and coworkers and the 2017 ILAE epilepsies classification, we performed a literature review in PubMed. A few discrete presentations can be identified: Parkinsonism as a late manifestation of complex neurodevelopmental disorders, characterized by developmental and epileptic encephalopathies (DE-EE), with multiple, refractory seizure types and severely abnormal EEG characteristics, with or without preceding hyperkinetic MD; Parkinsonism in the context of syndromic conditions with unspecific reduced seizure threshold in infancy and childhood; neurodegenerative conditions with brain iron accumulation, in which childhood DE-EE is followed by neurodegeneration; and finally, monogenic juvenile Parkinsonism, in which a subset of patients with intellectual disability or developmental delay (ID/DD) develop hypokinetic MD between 10 and 30 years of age, following unspecific, usually well-controlled, childhood epilepsy. This emerging group of genetic conditions leading to epilepsy or DE-EE in childhood followed by juvenile Parkinsonism highlights the need for careful long-term follow-up, especially in the context of ID/DD, in order to readily identify individuals at increased risk of later Parkinsonism.
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Affiliation(s)
- Carlotta Spagnoli
- Child Neurology and Psychiatry Unit, Department of Pediatrics, Presidio Ospedaliero Santa Maria Nuova, AUSL-IRCCS di Reggio Emilia, 42122 Reggio Emilia, Italy
- Correspondence: ; Tel.: +39-0522-296033
| | - Carlo Fusco
- Child Neurology and Psychiatry Unit, Department of Pediatrics, Presidio Ospedaliero Santa Maria Nuova, AUSL-IRCCS di Reggio Emilia, 42122 Reggio Emilia, Italy
| | - Francesco Pisani
- Human Neurosciences Department, Sapienza University of Rome, 00185 Rome, Italy
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Michetti C, Falace A, Benfenati F, Fassio A. Synaptic genes and neurodevelopmental disorders: From molecular mechanisms to developmental strategies of behavioral testing. Neurobiol Dis 2022; 173:105856. [PMID: 36070836 DOI: 10.1016/j.nbd.2022.105856] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 08/29/2022] [Accepted: 08/30/2022] [Indexed: 10/14/2022] Open
Abstract
Synaptopathies are a class of neurodevelopmental disorders caused by modification in genes coding for synaptic proteins. These proteins oversee the process of neurotransmission, mainly controlling the fusion and recycling of synaptic vesicles at the presynaptic terminal, the expression and localization of receptors at the postsynapse and the coupling between the pre- and the postsynaptic compartments. Murine models, with homozygous or heterozygous deletion for several synaptic genes or knock-in for specific pathogenic mutations, have been developed. They have proved to be extremely informative for understanding synaptic physiology, as well as for clarifying the patho-mechanisms leading to developmental delay, epilepsy and motor, cognitive and social impairments that are the most common clinical manifestations of neurodevelopmental disorders. However, the onset of these disorders emerges during infancy and adolescence while the behavioral phenotyping is often conducted in adult mice, missing important information about the impact of synaptic development and maturation on the manifestation of the behavioral phenotype. Here, we review the main achievements obtained by behavioral testing in murine models of synaptopathies and propose a battery of behavioral tests to improve classification, diagnosis and efficacy of potential therapeutic treatments. Our aim is to underlie the importance of studying behavioral development and better focusing on disease onset and phenotypes.
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Affiliation(s)
- Caterina Michetti
- Department of Experimental Medicine, University of Genoa, Genoa, Italy; Center for Synaptic Neuroscience, Istituto Italiano di Tecnologia, Genoa, Italy.
| | - Antonio Falace
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Children's Hospital A. Meyer-University of Florence, Florence, Italy
| | - Fabio Benfenati
- Center for Synaptic Neuroscience, Istituto Italiano di Tecnologia, Genoa, Italy; IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Anna Fassio
- Department of Experimental Medicine, University of Genoa, Genoa, Italy; IRCCS Ospedale Policlinico San Martino, Genoa, Italy.
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Mahdiannasser M, Rashidi-Nezhad A, Badv RS, Akrami SM. Exploring the genetic etiology of drug-resistant epilepsy: incorporation of exome sequencing into practice. Acta Neurol Belg 2022; 122:1457-1468. [PMID: 36127562 DOI: 10.1007/s13760-022-02095-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 09/05/2022] [Indexed: 11/25/2022]
Abstract
BACKGROUND By affecting about 50 million people worldwide, epilepsy is considered a global concern in neurology. Intolerable enough, up to ¼ of all patients do not respond to antiepileptic drugs and have recurring seizures. Therefore, revealing the underlying etiology is quite demanding in a clinical context to improve diagnosis and disease management. METHODS Initially, 85 patients suspected of epilepsy underwent thorough clinical and paraclinical evaluation and 24 individuals with drug-resistant epilepsy entered the study. Using whole-exome sequencing, the genetic etiology of drug-resistant epilepsy was investigated and discerned whether this method could facilitate the management of drug-resistant epilepsy through personalized medicine. Eventually, functional annotation was performed and drug-gene interaction networks were constructed to find potential therapeutic targets. RESULTS We found eleven novel variants in various genes including IRF2BPL, ST3GAL3, and GPAA1, for which a few epilepsy-related variants are available in public databases. The overall diagnostic yield for likely pathogenic and pathogenic variants and the detection rate of novel variants were 25% and 84.6%, respectively. Based on the results, two patients were considered potential candidates for personalized medicine. The highest number of interaction with drugs was demonstrated for SCN1A, SCN2A, and GRIN2A genes. CONCLUSIONS This study highlighted the importance of consanguineous marriage in drug-resistant epilepsy and suggested the possibility of reduced penetrance and variable expressivity in some of the autosomal dominant cases. We also suggest that whole-exome sequencing could facilitate personalized management of drug-resistant epilepsy. Regarding drug-gene interactions, some genes such as SCN1A and SCN2A might serve as therapeutic targets in drug-resistant epilepsy.
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Affiliation(s)
- Mojdeh Mahdiannasser
- Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Poursina St., P.O. Box:14176-13151, Tehran, Iran
| | - Ali Rashidi-Nezhad
- Maternal, Fetal and Neonatal Research Center, Family Health Research Institute, Tehran University of Medical Sciences, Tehran, Iran.,Genetics Ward, Yas Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran
| | - Reza Shervin Badv
- Children's Medical Center, Pediatrics Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Seyed Mohammad Akrami
- Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Poursina St., P.O. Box:14176-13151, Tehran, Iran.
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Shao Q, Shi X, Ma B, Zeng J, Zheng A, Xie W. TBC1D24-related familial infantile multifocal myoclonus: Description of a new Chinese pedigree with a 20 year follow up. Epilepsy Res 2022; 182:106923. [DOI: 10.1016/j.eplepsyres.2022.106923] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 03/24/2022] [Accepted: 04/05/2022] [Indexed: 11/26/2022]
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New avenues in molecular genetics for the diagnosis and application of therapeutics to the epilepsies. Epilepsy Behav 2021; 121:106428. [PMID: 31400936 DOI: 10.1016/j.yebeh.2019.07.029] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Revised: 06/14/2019] [Accepted: 07/06/2019] [Indexed: 11/22/2022]
Abstract
Genetic epidemiology studies have shown that most epilepsies involve some genetic cause. In addition, twin studies have helped strengthen the hypothesis that in most patients with epilepsy, a complex inheritance is involved. More recently, with the development of high-density single-nucleotide polymorphism (SNP) microarrays and next-generation sequencing (NGS) technologies, the discovery of genes related to the epilepsies has accelerated tremendously. Especially, the use of whole exome sequencing (WES) has had a considerable impact on the identification of rare genetic variants with large effect sizes, including inherited or de novo mutations in severe forms of childhood epilepsies. The identification of pathogenic variants in patients with these childhood epilepsies provides many benefits for patients and families, such as the confirmation of the genetic nature of the diseases. This process will allow for better genetic counseling, more accurate therapy decisions, and a significant positive emotional impact. However, to study the genetic component of the more common forms of epilepsy, the use of high-density SNP arrays in genome-wide association studies (GWAS) seems to be the strategy of choice. As such, researchers can identify loci containing genetic variants associated with the common forms of epilepsy. The knowledge generated over the past two decades about the effects of the mutations that cause the monogenic epilepsy is tremendous; however, the scientific community is just starting to apply this information in order to generate better target treatments.
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Genetic architecture and phenotypic landscape of deafness and onychodystrophy syndromes. Hum Genet 2021; 141:821-838. [PMID: 34232384 DOI: 10.1007/s00439-021-02310-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 06/28/2021] [Indexed: 10/20/2022]
Abstract
Deafness and onychodystrophy syndromes are a group of phenotypically overlapping syndromes, which include DDOD syndrome (dominant deafness-onychodystrophy), DOORS syndrome (deafness, onychodystrophy, osteodystrophy, mental retardation and seizures) and Zimmermann-Laband syndrome (gingival hypertrophy, coarse facial features, hypoplasia or aplasia of nails and terminal phalanges, intellectual disability, and hypertrichosis). Pathogenic variants in four genes, ATP6V1B2, TBC1D24, KCNH1 and KCNN3, have been shown to be associated with deafness and onychodystrophy syndromes. ATP6V1B2 encodes a component of the vacuolar H+-ATPase (V-ATPase) and TBC1D24 belongs to GTPase-activating protein, which are all involved in the regulation of membrane trafficking. The overlapping clinical phenotype of TBC1D24- and ATP6V1B2- related diseases and their function with GTPases or ATPases activity indicate that they may have some physiological link. Variants in genes encoding potassium channels KCNH1 or KCNN3, underlying human Zimmermann-Laband syndrome, have only recently been recognized. Although further analysis will be needed, these findings will help to elucidate an understanding of the pathogenesis of these disorders better and will aid in the development of potential therapeutic approaches. In this review, we summarize the latest developments of clinical features and molecular basis that have been reported to be associated with deafness and onychodystrophy disorders and highlight the challenges that may arise in the differential diagnosis.
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Venti V, Ciccia L, Scalia B, Sciuto L, Cimino C, Marino S, Praticò AD, Falsaperla R. KCNT1-Related Epilepsy: A Review. JOURNAL OF PEDIATRIC NEUROLOGY 2021. [DOI: 10.1055/s-0041-1728688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Abstract
KCNT1 gene encodes the sodium-dependent potassium channel reported as a causal factor for several different epileptic disorders. The gene has been also linked with cardiac disorders and in a family to sudden unexpected death in epilepsy. KCNT1 mutations, in most cases, result in a gain of function causing a neuronal hyperpolarization with loss of inhibition. Many early-onset epileptic encephalopathies related to gain of function of KCNT1 gene have been described, most often associated with two phenotypes: malignant migrating focal seizures of infancy and familial autosomal-dominant nocturnal frontal lobe epilepsy; however, there is no clear phenotype–genotype correlation, in fact same mutations have been represented in patients with West syndrome, Ohtahara syndrome, and early myoclonic encephalopathy. Additional neurologic features include intellectual disability, psychiatric disorders, hypotonia, microcephaly, strabismus, and movement disorders. Conventional anticonvulsant, vagal stimulation, and ketogenic diet have been used in the absence of clinical benefit in individuals with KCNT1-related epilepsy; in some patients, quinidine therapy off-label has been practiced successfully. This review aims to describe the characteristics of the gene, the phenotypes related to genetic mutations with the possible genotype–phenotype correlations and the treatments proposed to date, discussing the comorbidities reported in the literature.
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Affiliation(s)
- Valeria Venti
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Lina Ciccia
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Bruna Scalia
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Laura Sciuto
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Carla Cimino
- Unit of Pediatrics and Pediatric Emergency, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
| | - Simona Marino
- Unit of Neonatal Intensive Care and Neonatology, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
| | - Andrea D. Praticò
- Unit of Rare Diseases of the Nervous System in Childhood, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Raffaele Falsaperla
- Unit of Pediatrics and Pediatric Emergency, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
- Unit of Neonatal Intensive Care and Neonatology, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
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Timpanaro T, La Mendola F, Billone S, Nora AD, Collotta A, Sauna A, Salafia S, Falsaperla R. TBC1D24 and Its Related Epileptic Encephalopathy. JOURNAL OF PEDIATRIC NEUROLOGY 2021. [DOI: 10.1055/s-0041-1728645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Abstract
TBC1D24, mapped to 16p13.3, encodes a protein containing a Tre2/Bub2/Cdc16 (TBC) domain, belonging to the super-family of Rab GTPase activating proteins (Rab-GAP). These proteins regulate various functions, including the regulation of the traffic of the vesicular membrane. Several TBC1D24 mutations have been related to autosomal recessive neurological disorders, including severe developmental encephalopathies with malignant early childhood epilepsy, benign epilepsy, epileptic encephalopathy, and a complex neurological syndrome characterized by deafness, onychodystrophy, bone and neurological degeneration. Mutations of TBC1D24 have also been reported in patients with nonsyndromic deafness with dominant or recessive inheritance. Mechanisms underlying TBC1D24-associated disorders and the functions of TBC1D24 products in the generation of such complex spectrum of diseases remain partly unclear and future studies are needed to clarify this aspect, in order to improve the management of seizures and for the prevention of complication (including death) of newly diagnosed patients affected by TBC1D24-related disorders.
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Affiliation(s)
- Tiziana Timpanaro
- Unit of Rare Diseases of the Nervous System in Childhood, Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, Catania, Italy
| | | | - Sebastiano Billone
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Alessandra Di Nora
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Ausilia Collotta
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Alessandra Sauna
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | | | - Raffaele Falsaperla
- Unit of Pediatrics and Pediatric Emergency, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
- Unit of Neonatal Intensive Care and Neonatology, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
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Morimune T, Tano A, Tanaka Y, Yukiue H, Yamamoto T, Tooyama I, Maruo Y, Nishimura M, Mori M. Gm14230 controls Tbc1d24 cytoophidia and neuronal cellular juvenescence. PLoS One 2021; 16:e0248517. [PMID: 33886577 PMCID: PMC8062039 DOI: 10.1371/journal.pone.0248517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Accepted: 02/28/2021] [Indexed: 11/19/2022] Open
Abstract
It is not fully understood how enzymes are regulated in the tiny reaction field of a cell. Several enzymatic proteins form cytoophidia, a cellular macrostructure to titrate enzymatic activities. Here, we show that the epileptic encephalopathy-associated protein Tbc1d24 forms cytoophidia in neuronal cells both in vitro and in vivo. The Tbc1d24 cytoophidia are distinct from previously reported cytoophidia consisting of inosine monophosphate dehydrogenase (Impdh) or cytidine-5'-triphosphate synthase (Ctps). Tbc1d24 cytoophidia is induced by loss of cellular juvenescence caused by depletion of Gm14230, a juvenility-associated lncRNA (JALNC) and zeocin treatment. Cytoophidia formation is associated with impaired enzymatic activity of Tbc1d24. Thus, our findings reveal the property of Tbc1d24 to form cytoophidia to maintain neuronal cellular juvenescence.
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Affiliation(s)
- Takao Morimune
- Molecular Neuroscience Research Center (MNRC), Shiga University of Medical Science, Seta Tsukinowa-cho, Otsu, Shiga, Japan
- Department of Pediatrics, Shiga University of Medical Science, Seta Tsukinowa-cho, Otsu, Shiga, Japan
- Department of Vascular Physiology, National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka, Japan
| | - Ayami Tano
- Molecular Neuroscience Research Center (MNRC), Shiga University of Medical Science, Seta Tsukinowa-cho, Otsu, Shiga, Japan
- Department of Vascular Physiology, National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka, Japan
| | - Yuya Tanaka
- Molecular Neuroscience Research Center (MNRC), Shiga University of Medical Science, Seta Tsukinowa-cho, Otsu, Shiga, Japan
- Department of Vascular Physiology, National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka, Japan
| | - Haruka Yukiue
- Molecular Neuroscience Research Center (MNRC), Shiga University of Medical Science, Seta Tsukinowa-cho, Otsu, Shiga, Japan
| | - Takefumi Yamamoto
- Central Research Laboratory, Shiga University of Medical Science, Seta Tsukinowa-cho, Otsu, Shiga, Japan
| | - Ikuo Tooyama
- Molecular Neuroscience Research Center (MNRC), Shiga University of Medical Science, Seta Tsukinowa-cho, Otsu, Shiga, Japan
| | - Yoshihiro Maruo
- Department of Pediatrics, Shiga University of Medical Science, Seta Tsukinowa-cho, Otsu, Shiga, Japan
| | - Masaki Nishimura
- Molecular Neuroscience Research Center (MNRC), Shiga University of Medical Science, Seta Tsukinowa-cho, Otsu, Shiga, Japan
| | - Masaki Mori
- Molecular Neuroscience Research Center (MNRC), Shiga University of Medical Science, Seta Tsukinowa-cho, Otsu, Shiga, Japan
- Department of Vascular Physiology, National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka, Japan
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13
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El Halabi T, Dirani M, Hotait M, Nasreddine W, Beydoun A. A novel possible familial cause of epilepsy of infancy with migrating focal seizures related to SZT2 gene variant. Epilepsia Open 2021; 6:73-78. [PMID: 33681650 PMCID: PMC7918305 DOI: 10.1002/epi4.12451] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 11/10/2020] [Accepted: 11/22/2020] [Indexed: 12/31/2022] Open
Abstract
Seizure threshold-2 (SZT2) gene variants have been associated with a decrease in seizure threshold resulting in variable phenotypic expressions ranging from mild-moderate intellectual disabilities without seizures, to an early-onset epileptic encephalopathy with severe cognitive impairment. In addition, hypotonia and distinctive facial dysmorphism, including a high forehead and to a lesser extent ptosis and down-slanting palpebral fissures, were present in the majority. We herein report a novel SZT2 variant in one of two siblings both diagnosed with epilepsy of infancy with migrating focal seizures (EIMFS). This report is the fourth to document a possible familial case in EIMFS, a condition that was not previously associated with SZT2 variant. This report expands the phenotypic expression of SZT2, corroborates the importance of genetic counseling in some cases of EIMFS, and highlights the efficacy of potassium bromide in controlling the seizures associated with this condition.
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Affiliation(s)
- Tarek El Halabi
- Neurology DepartmentAmerican University of Beirut Medical CenterBeirutLebanon
| | - Maya Dirani
- Neurology DepartmentAmerican University of Beirut Medical CenterBeirutLebanon
| | - Mostafa Hotait
- Neurology DepartmentAmerican University of Beirut Medical CenterBeirutLebanon
| | - Wassim Nasreddine
- Neurology DepartmentAmerican University of Beirut Medical CenterBeirutLebanon
| | - Ahmad Beydoun
- Neurology DepartmentAmerican University of Beirut Medical CenterBeirutLebanon
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14
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De novo 16p13.3-p12.3 duplication in a child with syndromic developmental delay. GENE REPORTS 2020. [DOI: 10.1016/j.genrep.2020.100690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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15
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Scheffer IE, Boysen KE, Schneider AL, Myers CT, Mehaffey MG, Rochtus AM, Yuen YP, Ronen GM, Chak WK, Gill D, Poduri A, Mefford HC. BRAT1 encephalopathy: a recessive cause of epilepsy of infancy with migrating focal seizures. Dev Med Child Neurol 2020; 62:1096-1099. [PMID: 31868227 DOI: 10.1111/dmcn.14428] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/04/2019] [Indexed: 01/03/2023]
Abstract
Epilepsy of infancy with migrating focal seizures (EIMFS), one of the most severe developmental and epileptic encephalopathy syndromes, is characterized by seizures that migrate from one hemisphere to the other. EIMFS is genetically heterogeneous with 33 genes. We report five patients with EIMFS caused by recessive BRAT1 variants, identified via next generation sequencing. Recessive pathogenic variants in BRAT1 cause the rigidity and multifocal seizure syndrome, lethal neonatal with hypertonia, microcephaly, and intractable multifocal seizures. The epileptology of BRAT1 encephalopathy has not been well described. All five patients were profoundly impaired with seizure onset in the first week of life and focal seizure migration between hemispheres. We show that BRAT1 is an important recessive cause of EIMFS with onset in the first week of life, profound impairment, and early death. Early recognition of this genetic aetiology will inform management and reproductive counselling.
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Affiliation(s)
- Ingrid E Scheffer
- Epilepsy Research Centre, Department of Medicine, Austin Health, University of Melbourne, Heidelberg, Victoria, Australia.,Florey Institute of Neuroscience and Mental Health, Heidelberg, Victoria, Australia.,Murdoch Children's Research Institute, Parkville, Victoria, Australia.,Department of Paediatrics, Royal Children's Hospital, Parkville, Victoria, Australia
| | - Katja E Boysen
- Epilepsy Research Centre, Department of Medicine, Austin Health, University of Melbourne, Heidelberg, Victoria, Australia
| | - Amy L Schneider
- Epilepsy Research Centre, Department of Medicine, Austin Health, University of Melbourne, Heidelberg, Victoria, Australia
| | - Candace T Myers
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, WA, USA
| | - Michele G Mehaffey
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, WA, USA
| | - Anne M Rochtus
- Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital, Boston, MA, USA.,Department of Neurology, Harvard Medical School, Boston, MA, USA
| | | | - Gabriel M Ronen
- Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada
| | - Wai Km Chak
- Tuen Mun Hospital, New Territories, West Cluster, Hong Kong
| | - Deepak Gill
- T. Y. Nelson Department of Neurology and Neurosurgery, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Annapurna Poduri
- Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital, Boston, MA, USA.,Department of Neurology, Harvard Medical School, Boston, MA, USA
| | - Heather C Mefford
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, WA, USA
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16
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Lüthy K, Mei D, Fischer B, De Fusco M, Swerts J, Paesmans J, Parrini E, Lubarr N, Meijer IA, Mackenzie KM, Lee WT, Cittaro D, Aridon P, Schoovaerts N, Versées W, Verstreken P, Casari G, Guerrini R. TBC1D24-TLDc-related epilepsy exercise-induced dystonia: rescue by antioxidants in a disease model. Brain 2020; 142:2319-2335. [PMID: 31257402 DOI: 10.1093/brain/awz175] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 04/08/2019] [Accepted: 04/25/2019] [Indexed: 11/13/2022] Open
Abstract
Genetic mutations in TBC1D24 have been associated with multiple phenotypes, with epilepsy being the main clinical manifestation. The TBC1D24 protein consists of the unique association of a Tre2/Bub2/Cdc16 (TBC) domain and a TBC/lysin motif domain/catalytic (TLDc) domain. More than 50 missense and loss-of-function mutations have been described and are spread over the entire protein. Through whole genome/exome sequencing we identified compound heterozygous mutations, R360H and G501R, within the TLDc domain, in an index family with a Rolandic epilepsy exercise-induced dystonia phenotype (http://omim.org/entry/608105). A 20-year long clinical follow-up revealed that epilepsy was self-limited in all three affected patients, but exercise-induced dystonia persisted into adulthood in two. Furthermore, we identified three additional sporadic paediatric patients with a remarkably similar phenotype, two of whom had compound heterozygous mutations consisting of an in-frame deletion I81_K84 and an A500V mutation, and the third carried T182M and G511R missense mutations, overall revealing that all six patients harbour a missense mutation in the subdomain of TLDc between residues 500 and 511. We solved the crystal structure of the conserved Drosophila TLDc domain. This allowed us to predict destabilizing effects of the G501R and G511R mutations and, to a lesser degree, of R360H and potentially A500V. Next, we characterized the functional consequences of a strong and a weak TLDc mutation (TBC1D24G501R and TBC1D24R360H) using Drosophila, where TBC1D24/Skywalker regulates synaptic vesicle trafficking. In a Drosophila model neuronally expressing human TBC1D24, we demonstrated that the TBC1D24G501R TLDc mutation causes activity-induced locomotion and synaptic vesicle trafficking defects, while TBC1D24R360H is benign. The neuronal phenotypes of the TBC1D24G501R mutation are consistent with exacerbated oxidative stress sensitivity, which is rescued by treating TBC1D24G501R mutant animals with antioxidants N-acetylcysteine amide or α-tocopherol as indicated by restored synaptic vesicle trafficking levels and sustained behavioural activity. Our data thus show that mutations in the TLDc domain of TBC1D24 cause Rolandic-type focal motor epilepsy and exercise-induced dystonia. The humanized TBC1D24G501R fly model exhibits sustained activity and vesicle transport defects. We propose that the TBC1D24/Sky TLDc domain is a reactive oxygen species sensor mediating synaptic vesicle trafficking rates that, when dysfunctional, causes a movement disorder in patients and flies. The TLDc and TBC domain mutations' response to antioxidant treatment we observed in the animal model suggests a potential for combining antioxidant-based therapeutic approaches to TBC1D24-associated disorders with previously described lipid-altering strategies for TBC domain mutations.
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Affiliation(s)
- Kevin Lüthy
- VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium.,KU Leuven, Department of Neurosciences, Leuven Brain Institute, Leuven, Belgium
| | - Davide Mei
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Children's Hospital A. Meyer-University of Florence, Florence, Italy
| | - Baptiste Fischer
- VIB-VUB Center for Structural Biology, Brussels, Belgium.,Vrije Universiteit Brussel, Structural Biology Brussels, Brussels, Belgium
| | | | - Jef Swerts
- VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium.,KU Leuven, Department of Neurosciences, Leuven Brain Institute, Leuven, Belgium
| | - Jone Paesmans
- VIB-VUB Center for Structural Biology, Brussels, Belgium.,Vrije Universiteit Brussel, Structural Biology Brussels, Brussels, Belgium
| | - Elena Parrini
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Children's Hospital A. Meyer-University of Florence, Florence, Italy
| | - Naomi Lubarr
- Mount Sinai Beth Israel, Department of Neurology, New York, NY, USA
| | - Inge A Meijer
- Department of Pediatrics and Neurosciences, CHU Sainte-Justine and University of Montreal, Montreal, Canada
| | | | - Wang-Tso Lee
- Department of Pediatrics, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan
| | | | - Paolo Aridon
- Department of Experimental Biomedicine and Clinical Neurosciences, University of Palermo, Palermo, Italy
| | - Nils Schoovaerts
- VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium.,KU Leuven, Department of Neurosciences, Leuven Brain Institute, Leuven, Belgium
| | - Wim Versées
- VIB-VUB Center for Structural Biology, Brussels, Belgium.,Vrije Universiteit Brussel, Structural Biology Brussels, Brussels, Belgium
| | - Patrik Verstreken
- VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium.,KU Leuven, Department of Neurosciences, Leuven Brain Institute, Leuven, Belgium
| | - Giorgio Casari
- San Raffaele University, Milan, Italy.,Telethon Institute of Genetics and Medicine, Naples, Italy
| | - Renzo Guerrini
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Children's Hospital A. Meyer-University of Florence, Florence, Italy.,IRCCS Fondazione Stella Maris, Pisa, Italy
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17
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Salemi M, Cali’ F, Giambirtone M, Elia M, Romano C. TBC1D24 gene mRNA expression in a boy with early infantile epileptic encephalopathy-16. Acta Neurol Belg 2020; 120:381-383. [PMID: 28726039 DOI: 10.1007/s13760-017-0818-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 07/15/2017] [Indexed: 10/19/2022]
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18
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Abstract
Developmental and epileptic encephalopathies (DEEs) are a group of severe, early onset epilepsies characterized by refractory seizures, developmental delay or regression associated with ongoing epileptic activity, and generally poor prognosis. DEE is genetically and phenotypically heterogeneous, and there is a plethora of genetic testing options to investigate the rapidly growing list of epilepsy genes. However, more than 50% of patients with DEE remain without a genetic diagnosis despite state-of-the-art genetic testing. In this review, we discuss the major advances in epilepsy genomics that have surfaced in recent years. The goal of this review is to reach a larger audience and build a better understanding of pathogenesis and genetic testing options in DEE.
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Affiliation(s)
- Malavika Hebbar
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, WA, 98105, USA
| | - Heather C Mefford
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, WA, 98105, USA
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19
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Tona R, Chen W, Nakano Y, Reyes LD, Petralia RS, Wang YX, Starost MF, Wafa TT, Morell RJ, Cravedi KD, du Hoffmann J, Miyoshi T, Munasinghe JP, Fitzgerald TS, Chudasama Y, Omori K, Pierpaoli C, Banfi B, Dong L, Belyantseva IA, Friedman TB. The phenotypic landscape of a Tbc1d24 mutant mouse includes convulsive seizures resembling human early infantile epileptic encephalopathy. Hum Mol Genet 2020; 28:1530-1547. [PMID: 30602030 DOI: 10.1093/hmg/ddy445] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 12/02/2018] [Accepted: 12/11/2018] [Indexed: 12/19/2022] Open
Abstract
Epilepsy, deafness, onychodystrophy, osteodystrophy and intellectual disability are associated with a spectrum of mutations of human TBC1D24. The mechanisms underlying TBC1D24-associated disorders and the functions of TBC1D24 are not well understood. Using CRISPR-Cas9 genome editing, we engineered a mouse with a premature translation stop codon equivalent to human S324Tfs*3, a recessive mutation of TBC1D24 associated with early infantile epileptic encephalopathy (EIEE). Homozygous S324Tfs*3 mice have normal auditory and vestibular functions but show an abrupt onset of spontaneous seizures at postnatal day 15 recapitulating human EIEE. The S324Tfs*3 variant is located in an alternatively spliced micro-exon encoding six perfectly conserved amino acids incorporated postnatally into TBC1D24 protein due to a micro-exon utilization switch. During embryonic and early postnatal development, S324Tfs*3 homozygotes produce predominantly the shorter wild-type TBC1D24 protein isoform that omits the micro-exon. S324Tfs*3 homozygotes show an abrupt onset of seizures at P15 that correlates with a developmental switch to utilization of the micro-exon. A mouse deficient for alternative splice factor SRRM3 impairs incorporation of the Tbc1d24 micro-exon. Wild-type Tbc1d24 mRNA is abundantly expressed in the hippocampus using RNAscope in situ hybridization. Immunogold electron microscopy using a TBC1D24-specific antibody revealed that TBC1D24 is associated with clathrin-coated vesicles and synapses of hippocampal neurons, suggesting a crucial role of TBC1D24 in vesicle trafficking important for neuronal signal transmission. This is the first characterization of a mouse model of human TBC1D24-associated EIEE that can now be used to screen for antiepileptogenic drugs ameliorating TBCID24 seizure disorders.
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Affiliation(s)
- Risa Tona
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, Porter Neuroscience Research Center, National Institutes of Health, Bethesda, MD, USA.,Department of Otolaryngology, Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Wenqian Chen
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, Porter Neuroscience Research Center, National Institutes of Health, Bethesda, MD, USA
| | - Yoko Nakano
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Laura D Reyes
- Quantitative Medical Imaging Section, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD, USA
| | - Ronald S Petralia
- Advanced Imaging Core, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | - Ya-Xian Wang
- Advanced Imaging Core, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | - Matthew F Starost
- Division of Veterinary Resources, National Institutes of Health, Bethesda, MD, USA
| | - Talah T Wafa
- Mouse Auditory Testing Core Facility, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | - Robert J Morell
- Genomics and Computational Biology Core, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | - Kevin D Cravedi
- Rodent Behavioral Core, National Institute of Mental Health, Porter Neuroscience Research Center, National Institutes of Health, Bethesda, MD, USA
| | - Johann du Hoffmann
- Rodent Behavioral Core, National Institute of Mental Health, Porter Neuroscience Research Center, National Institutes of Health, Bethesda, MD, USA
| | - Takushi Miyoshi
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, Porter Neuroscience Research Center, National Institutes of Health, Bethesda, MD, USA
| | - Jeeva P Munasinghe
- Mouse Imaging Facility, In vivo NMR Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Tracy S Fitzgerald
- Mouse Auditory Testing Core Facility, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | - Yogita Chudasama
- Rodent Behavioral Core, National Institute of Mental Health, Porter Neuroscience Research Center, National Institutes of Health, Bethesda, MD, USA.,Section on Behavioral Neuroscience, National Institute of Mental Health, Porter Neuroscience Research Center, National Institutes of Health, Bethesda, MD, USA
| | - Koichi Omori
- Department of Otolaryngology, Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Carlo Pierpaoli
- Quantitative Medical Imaging Section, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD, USA
| | - Botond Banfi
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Lijin Dong
- Genetic Engineering Core, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Inna A Belyantseva
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, Porter Neuroscience Research Center, National Institutes of Health, Bethesda, MD, USA
| | - Thomas B Friedman
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, Porter Neuroscience Research Center, National Institutes of Health, Bethesda, MD, USA
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20
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Mao X, Bruneau N, Gao Q, Becq H, Jia Z, Xi H, Shu L, Wang H, Szepetowski P, Aniksztejn L. The Epilepsy of Infancy With Migrating Focal Seizures: Identification of de novo Mutations of the KCNT2 Gene That Exert Inhibitory Effects on the Corresponding Heteromeric K Na1.1/K Na1.2 Potassium Channel. Front Cell Neurosci 2020; 14:1. [PMID: 32038177 PMCID: PMC6992647 DOI: 10.3389/fncel.2020.00001] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 01/06/2020] [Indexed: 12/21/2022] Open
Abstract
The epilepsy of infancy with migrating focal seizures (EIMFS; previously called Malignant migrating partial seizures of infancy) are early-onset epileptic encephalopathies (EOEE) that associate multifocal ictal discharges and profound psychomotor retardation. EIMFS have a genetic origin and are mostly caused by de novo mutations in the KCNT1 gene, and much more rarely in the KCNT2 gene. KCNT1 and KCNT2 respectively encode the KNa1.1 (Slack) and KNa1.2 (Slick) subunits of the sodium-dependent voltage-gated potassium channel KNa. Functional analyses of the corresponding mutant homomeric channels in vitro suggested gain-of-function effects. Here, we report two novel, de novo truncating mutations of KCNT2: one mutation is frameshift (p.L48Qfs43), is situated in the N-terminal domain, and was found in a patient with EOEE (possibly EIMFS); the other mutation is nonsense (p.K564*), is located in the C-terminal region, and was found in a typical EIMFS patient. Using whole-cell patch-clamp recordings, we have analyzed the functional consequences of those two novel KCNT2 mutations on reconstituted KNa1.2 homomeric and KNa1.1/KNa1.2 heteromeric channels in transfected chinese hamster ovary (CHO) cells. We report that both mutations significantly impacted on KNa function; notably, they decreased the global current density of heteromeric channels by ~25% (p.K564*) and ~55% (p.L48Qfs43). Overall our data emphasize the involvement of KCNT2 in EOEE and provide novel insights into the role of heteromeric KNa channel in the severe KCNT2-related epileptic phenotypes. This may have important implications regarding the elaboration of future treatment.
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Affiliation(s)
- Xiao Mao
- Hunan Provincial Maternal and Child Health Care Hospital, Changsha, China
- NHC Key Laboratory of Birth Defects Research, Prevention and Treatment, Changsha, China
| | - Nadine Bruneau
- INSERM, Aix-Marseille University, INMED, UMR1249, Marseille, France
| | - Quwen Gao
- Department of Epilepsy, General Hospital of Southern Theater Command, Guangzhou, China
| | - Hélène Becq
- INSERM, Aix-Marseille University, INMED, UMR1249, Marseille, France
| | - Zhengjun Jia
- Hunan Provincial Maternal and Child Health Care Hospital, Changsha, China
- NHC Key Laboratory of Birth Defects Research, Prevention and Treatment, Changsha, China
| | - Hui Xi
- Hunan Provincial Maternal and Child Health Care Hospital, Changsha, China
- NHC Key Laboratory of Birth Defects Research, Prevention and Treatment, Changsha, China
| | - Li Shu
- Hunan Provincial Maternal and Child Health Care Hospital, Changsha, China
- NHC Key Laboratory of Birth Defects Research, Prevention and Treatment, Changsha, China
| | - Hua Wang
- Hunan Provincial Maternal and Child Health Care Hospital, Changsha, China
- NHC Key Laboratory of Birth Defects Research, Prevention and Treatment, Changsha, China
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21
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Kuchenbuch M, Barcia G, Chemaly N, Carme E, Roubertie A, Gibaud M, Van Bogaert P, de Saint Martin A, Hirsch E, Dubois F, Sarret C, Nguyen The Tich S, Laroche C, des Portes V, Billette de Villemeur T, Barthez MA, Auvin S, Bahi-Buisson N, Desguerre I, Kaminska A, Benquet P, Nabbout R. KCNT1 epilepsy with migrating focal seizures shows a temporal sequence with poor outcome, high mortality and SUDEP. Brain 2019; 142:2996-3008. [DOI: 10.1093/brain/awz240] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 06/11/2019] [Accepted: 06/14/2019] [Indexed: 11/14/2022] Open
Abstract
Data on KCNT1 epilepsy of infancy with migrating focal seizures are heterogeneous and incomplete. Kuchenbuch et al. refine the syndrome phenotype, showing a three-step temporal sequence, poor prognosis with acquired microcephaly, high prevalence of extra-neurological manifestations and early mortality, particularly due to SUDEP. Refining the electro-clinical spectrum should facilitate early diagnosis.
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Affiliation(s)
- Mathieu Kuchenbuch
- University Rennes, CHU Rennes (Department of Clinical neurophysiology), Inserm, LTSI (Laboratoire de Traitement du Signal et de l’Image), UMR-1099, F-35000 Rennes, France
- Reference Centre for Rare Epilepsies, Department of Pediatric Neurology, Necker Enfants Malades Hospital, Paris Descartes University, Paris, France
- Institut Imagine, INSERM UMR 1163, Translational research for neurological disorder, France
| | - Giulia Barcia
- Reference Centre for Rare Epilepsies, Department of Pediatric Neurology, Necker Enfants Malades Hospital, Paris Descartes University, Paris, France
- Institut Imagine, INSERM UMR 1163, Translational research for neurological disorder, France
- Department of Genetics, Necker Enfants Malades Hospital, Imagine Institute, France
| | - Nicole Chemaly
- Reference Centre for Rare Epilepsies, Department of Pediatric Neurology, Necker Enfants Malades Hospital, Paris Descartes University, Paris, France
- Institut Imagine, INSERM UMR 1163, Translational research for neurological disorder, France
| | - Emilie Carme
- Department of Pediatric Neurology, University of Montpellier, France
| | - Agathe Roubertie
- Department of Pediatric Neurology, University of Montpellier, France
| | - Marc Gibaud
- Department of Pediatric Neurology, Angers University Hospital, France
| | | | | | - Edouard Hirsch
- Department of Pediatric Neurology, Strasbourg University Hospital, France
| | - Fanny Dubois
- Department of Pediatric Neurology, CHU Grenoble Alpes, F-38000 Grenoble, France
| | | | | | - Cecile Laroche
- Department of Pediatric Neurology, Limoges University Hospital, France
| | - Vincent des Portes
- Department of Pediatric Neurology, CNRS UMR 5304, F- 69675 Bron, France
- Lyon-1 University, F-69008 Lyon, France
| | | | | | - Stéphane Auvin
- Université Paris Diderot, Sorbonne Paris Cité, INSERM UMR1141, Paris, France
- AP-HP, Hôpital Robert Debré, Service de Neurologie Pédiatrique, Paris, France
| | - Nadia Bahi-Buisson
- Reference Centre for Rare Epilepsies, Department of Pediatric Neurology, Necker Enfants Malades Hospital, Paris Descartes University, Paris, France
| | - Isabelle Desguerre
- Reference Centre for Rare Epilepsies, Department of Pediatric Neurology, Necker Enfants Malades Hospital, Paris Descartes University, Paris, France
| | - Anna Kaminska
- Reference Centre for Rare Epilepsies, Department of Pediatric Neurology, Necker Enfants Malades Hospital, Paris Descartes University, Paris, France
- AP-HP, Necker-Enfants Malades Hospital, Department of Clinical Neurophysiology, Paris, France
| | - Pascal Benquet
- University Rennes, CHU Rennes (Department of Clinical neurophysiology), Inserm, LTSI (Laboratoire de Traitement du Signal et de l’Image), UMR-1099, F-35000 Rennes, France
| | - Rima Nabbout
- Reference Centre for Rare Epilepsies, Department of Pediatric Neurology, Necker Enfants Malades Hospital, Paris Descartes University, Paris, France
- Institut Imagine, INSERM UMR 1163, Translational research for neurological disorder, France
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22
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Zhang J, Chen J, Zeng Q, Zhang L, Tian X, Yang X, Yang Z, Wu Y, Wu X, Zhang Y. Infantile epilepsy with multifocal myoclonus caused by TBC1D24 mutations. Seizure 2019; 69:228-234. [DOI: 10.1016/j.seizure.2019.05.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 05/09/2019] [Accepted: 05/11/2019] [Indexed: 11/16/2022] Open
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23
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Milh M, Riccardi F, Denis J. Genetics of neonatal onset epilepsies: An overview. Rev Neurol (Paris) 2019; 176:2-9. [PMID: 31097300 DOI: 10.1016/j.neurol.2019.01.396] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 01/03/2019] [Accepted: 01/08/2019] [Indexed: 11/29/2022]
Abstract
The weight of monogenic abnormalities in the possible causes of epilepsy has grown significantly in recent years, due to the emergence of next-generation sequencing (NGS) techniques. Especially notable in early neonatal and infantile epilepsies, which seem to be explained by monogenic abnormalities. This short review focuses on the major genes associated with very early-onset epilepsies, where NGS techniques are most cost-effective: early infantile epileptic encephalopathy, early myoclonic encephalopathy, and other neonatal epilepsies. The discovery of the genetic mutation often follows several weeks or months of management, and rarely modifies it. However, clinical studies can sometimes better define medical treatment. The genetic causes of these epilepsies are very numerous and the pathophysiological knowledge very minimal. The big challenge for the coming years is to develop more targeted treatments based on research on animal models.
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Affiliation(s)
- M Milh
- Aix-Marseille université, Inserm, MMG, 58, boulevard Charles-Livon, 13009 Marseille, France; Pediatric neurology unit, Timone Children Hospital, AP-HM, 278, rue Saint-Pierre, 13005 Marseille, France.
| | - F Riccardi
- Pediatric neurology unit, Timone Children Hospital, AP-HM, 278, rue Saint-Pierre, 13005 Marseille, France
| | - J Denis
- Pediatric neurology unit, Timone Children Hospital, AP-HM, 278, rue Saint-Pierre, 13005 Marseille, France
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24
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Aprile D, Fruscione F, Baldassari S, Fadda M, Ferrante D, Falace A, Buhler E, Sartorelli J, Represa A, Baldelli P, Benfenati F, Zara F, Fassio A. TBC1D24 regulates axonal outgrowth and membrane trafficking at the growth cone in rodent and human neurons. Cell Death Differ 2019; 26:2464-2478. [PMID: 30858606 DOI: 10.1038/s41418-019-0313-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 01/25/2019] [Accepted: 02/20/2019] [Indexed: 01/04/2023] Open
Abstract
Mutations in TBC1D24 are described in patients with a spectrum of neurological diseases, including mild and severe epilepsies and complex syndromic phenotypes such as Deafness, Onycodystrophy, Osteodystrophy, Mental Retardation and Seizure (DOORS) syndrome. The product of TBC1D24 is a multifunctional protein involved in neuronal development, regulation of synaptic vesicle trafficking, and protection from oxidative stress. Although pathogenic mutations in TBC1D24 span the entire coding sequence, no clear genotype/phenotype correlations have emerged. However most patients bearing predicted loss of function mutations exhibit a severe neurodevelopmental disorder. Aim of the study is to investigate the impact of TBC1D24 knockdown during the first stages of neuronal differentiation when axonal specification and outgrowth take place. In rat cortical primary neurons silenced for TBC1D24, we found defects in axonal specification, the maturation of axonal initial segment and action potential firing. The axonal phenotype was accompanied by an impairment of endocytosis at the growth cone and an altered activation of the TBC1D24 molecular partner ADP ribosylation factor 6. Accordingly, acute knockdown of TBC1D24 in cerebrocortical neurons in vivo analogously impairs callosal projections. The axonal defect was also investigated in human induced pluripotent stem cell-derived neurons from patients carrying TBC1D24 mutations. Reprogrammed neurons from a patient with severe developmental encephalopathy show significant axon formation defect that were absent from reprogrammed neurons of a patient with mild early onset epilepsy. Our data reveal that alterations of membrane trafficking at the growth cone induced by TBC1D24 loss of function cause axonal and excitability defects. The axonal phenotype correlates with the disease severity and highlight an important role for TBC1D24 in connectivity during brain development.
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Affiliation(s)
- Davide Aprile
- Department of Experimental Medicine, University of Genoa, Genoa, Italy
| | - Floriana Fruscione
- Laboratory of Neurogenetics and Neuroscience, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Simona Baldassari
- Laboratory of Neurogenetics and Neuroscience, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Manuela Fadda
- Department of Experimental Medicine, University of Genoa, Genoa, Italy
| | - Daniele Ferrante
- Department of Experimental Medicine, University of Genoa, Genoa, Italy
| | - Antonio Falace
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Children's Hospital A. Meyer-University of Florence, Florence, Italy
| | | | - Jacopo Sartorelli
- Laboratory of Neurogenetics and Neuroscience, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Alfonso Represa
- INMED, Aix-Marseille University, INSERM U1249, Marseille, France
| | - Pietro Baldelli
- Department of Experimental Medicine, University of Genoa, Genoa, Italy.,IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Fabio Benfenati
- IRCCS Ospedale Policlinico San Martino, Genoa, Italy.,Center of Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genoa, Italy
| | - Federico Zara
- Laboratory of Neurogenetics and Neuroscience, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Anna Fassio
- Department of Experimental Medicine, University of Genoa, Genoa, Italy. .,IRCCS Ospedale Policlinico San Martino, Genoa, Italy.
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Nakashima M, Negishi Y, Hori I, Hattori A, Saitoh S, Saitsu H. A case of early-onset epileptic encephalopathy with a homozygous TBC1D24 variant caused by uniparental isodisomy. Am J Med Genet A 2019; 179:645-649. [PMID: 30680869 DOI: 10.1002/ajmg.a.61056] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 12/03/2018] [Accepted: 01/06/2019] [Indexed: 11/11/2022]
Abstract
TBC1D24-related disorders are rare neurodevelopmental disorders that show a broad range of neuropsychiatric deficits and are mostly inherited in an autosomal recessive manner. Here we describe a case with early-onset epileptic encephalopathy, in whom exome sequencing detected a novel pathogenic homozygous c.442G>A, p.(Glu148Lys) variant in TBC1D24. She showed severe developmental delay, congenital sensorineural hearing loss and seizures, but the combination of a high dose phenobarbital and potassium bromide was very effective for the seizures. Sanger sequencing revealed that her mother was a heterozygous carrier of the TBC1D24 variant, but her father showed only wild-type alleles. Homozygosity mapping analysis using exome data showed loss of the heterozygosity region at 16p13.3-p13.13 encompassing TBC1D24. Genotyping analysis using rare variants within loss of the heterozygosity region indicated that the patient has a homozygous haplotype inherited from her mother, indicating maternal segmental uniparental isodisomy (UPiD). These data clearly show that exome sequencing is a powerful tool to perform comprehensive genetic analysis.
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Affiliation(s)
- Mitsuko Nakashima
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Yutaka Negishi
- Department of Pediatrics and Neonatology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Ikumi Hori
- Department of Pediatrics and Neonatology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Ayako Hattori
- Department of Pediatrics and Neonatology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Shinji Saitoh
- Department of Pediatrics and Neonatology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Hirotomo Saitsu
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, Japan
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26
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Kholin AA, Zavadenko NN, Fedonyuk ID, Antonets AV, Mukhin KY, Malov AG, Vshivkov MI, Anisimov GV, Il'ina ES. Early infantile epileptic encephalopathy type 14: three cases of epilepsy in infancy with migrating focal seizures due to KCNT1 mutations. Zh Nevrol Psikhiatr Im S S Korsakova 2019. [DOI: 10.17116/jnevro201911907274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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27
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Cortès-Saladelafont E, Lipstein N, García-Cazorla À. Presynaptic disorders: a clinical and pathophysiological approach focused on the synaptic vesicle. J Inherit Metab Dis 2018; 41:1131-1145. [PMID: 30022305 DOI: 10.1007/s10545-018-0230-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 06/23/2018] [Accepted: 07/02/2018] [Indexed: 12/12/2022]
Abstract
The aim of this report is to present a tentative clinical and pathophysiological approach to diseases affecting the neuronal presynaptic terminal, with a major focus on synaptic vesicles (SVs). Diseases are classified depending on which step of the neurobiology of the SV is predominantly affected: (1) biogenesis of vesicle precursors in the neuronal soma; (2) transport along the axon; (3) vesicle cycle at the presynaptic terminal (exocytosis-endocytosis cycle, with the main purpose of neurotransmitter release). Given that SVs have been defined as individual organelles, we highlight the link between the biological processes disturbed by genetic mutations and the clinical presentation of these disorders. The great majority of diseases may present as epileptic encephalopathies, intellectual disability (syndromic or nonsyndromic) with/without autism spectrum disorder (and other neuropsychiatric symptoms), and movement disorders. These symptoms may overlap and present in patients as a combination of clinical signs that results in the spectrum of the synaptopathies. A small number of diseases may also exhibit neuromuscular signs. In general, SV disorders tend to be severe, early encephalopathies that interfere with neurodevelopment. As a consequence, developmental delay and intellectual disability are constant in almost all the defects described. Considering that some of these diseases might mimic other neurometabolic conditions (and in particular treatable disorders), an initial extensive metabolic workup should always be considered. Further knowledge into pathophysiological mechanisms and biomarkers, as well as descriptions of new presynaptic disorders, will probably take place in the near future.
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Affiliation(s)
- Elisenda Cortès-Saladelafont
- Department of Neurology, Neurometabolic Unit and Synaptic Metabolism Laboratory, Institut Pediàtric de Recerca and CIBERER, ISCIII, Hospital Sant Joan de Déu, Passeig Sant Joan de Déu, 2, 08950, Esplugues, Barcelona, Spain
| | - Noa Lipstein
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Àngels García-Cazorla
- Department of Neurology, Neurometabolic Unit and Synaptic Metabolism Laboratory, Institut Pediàtric de Recerca and CIBERER, ISCIII, Hospital Sant Joan de Déu, Passeig Sant Joan de Déu, 2, 08950, Esplugues, Barcelona, Spain.
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28
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Li J, Liu R, Feng H, Zhang J, Wang D, Wang Y, Zeng J, Fan Y. Novel TBC1D24 Mutations in a Case of Nonconvulsive Status Epilepticus. Front Neurol 2018; 9:623. [PMID: 30108545 PMCID: PMC6079244 DOI: 10.3389/fneur.2018.00623] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 07/10/2018] [Indexed: 01/19/2023] Open
Abstract
Objective: Nonconvulsive status epilepticus (NCSE) is an uncommon clinical manifestation in patients with TBC1D24 mutations. In addition, NCSE has not been reported as a syndrome together with cerebellar ataxia and ophthalmoplegia. Methods: We herein report the clinical and genetic features of a four-year-old patient with NCSE, cerebellar ataxia, and ophthalmoplegia caused by hitherto unidentified TBC1D24 mutations. We performed 24-h video electroencephalogram (EEG), magnetic resonance imaging, and gene sequencing on the patient and her parents to determine the diagnosis. Results: We identified a novel c.1416_1437del (p.Ser473Argfs*43) mutation, as well as the previously identified c.1499C>T (p.Ala500Val) mutation in TBC1D24, by using targeted next-generation sequencing. The novel mutation (inherited from the mother) is the first reported deletion mutation longer than 20 bp in TBC1D24. The p.Ala500Val mutation inherited from father has been reported in a German patient with infantile myoclonic, for whom results from the EEG and neuroimaging were normal. These two mutations resulted in the severe phenotypes observed in our patient Conclusions: The identification of the novel TBC1D24 mutation and consequent complicated clinical manifestations suggest that patients with NCSE and ataxia demand more attention. We further recommend that genetic test should be administered to these patients to avoid genetic inheritance of this mutation.
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Affiliation(s)
- Jingjing Li
- Department of Neurology and Stroke Center, First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Ruihong Liu
- Fifth Affiliated Hospital, Sun Yat-sen University-BGI Laboratory, Department of Experimental Medicine, Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, China
| | - Huiyu Feng
- Department of Neurology and Stroke Center, First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Jian Zhang
- Department of Neurology and Stroke Center, First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Dilong Wang
- Department of Neurology and Stroke Center, First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Yiming Wang
- Fifth Affiliated Hospital, Sun Yat-sen University-BGI Laboratory, Department of Experimental Medicine, Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, China.,Xinhua College, Sun Yat-sen University, Guangzhou, China
| | - Jinsheng Zeng
- Department of Neurology and Stroke Center, First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Yuhua Fan
- Department of Neurology and Stroke Center, First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
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29
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Qu X, Zhao B, Hu M, Ji Z, Xu J, Xia W, Qu Y. Downregulation of TBC1 Domain Family Member 24 (BC1D24) Inhibits Breast Carcinoma Growth via IGF1R/PI3K/AKT Pathway. Med Sci Monit 2018; 24:3987-3996. [PMID: 29893377 PMCID: PMC6029514 DOI: 10.12659/msm.906736] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND TBC1 domain family member 24 (TBC1D24) pathogenic mutations affect its binding to ARF6 and then result in severe impairment of neuronal development. However, there are no reports about the expression and function of TBC1D24 in cancer. The aim of the present study was to evaluate the effect of proliferation, migration, and invasion after silencing TBC1D24 expression in breast cancer MCF-7 cells, and to elucidate the potential mechanism of TBC1D24 in breast cancer. MATERIAL AND METHODS The expression of TBC1D24 in breast cancer tissues and the adjacent non-tumor tissues was determined by S-P immunohistochemistry. The malignant behavior, including proliferation, migration, and invasion ability, was determined after silencing TBC1D24 in breast cancer MCF-7 cells. The expression of IGF1R was determined after silencing TBC1D24. The expression of TBC1D24 and IGF1R was detected after transfecting miR-30a mimics or inhibitors. The effect of TBC1D24 on MCF-7 cells growth in vivo was evaluated by a tumor xenograft study. RESULTS TBC1D24 expression was elevated and was associated with poor outcome in breast carcinoma. TBC1D24 high expression was significantly correlated with unfavorable OS and RFS for breast cancer patients (p<0.05). Silencing TBC1D24 inhibited the proliferation, migration, and invasion ability of MCF-7 cells. TBC1D24 and IGF1R expression were decreased when transfected with miR-30a mimics. However, TBC1D24 and IGF1R expression were increased when transfected with miR-30a inhibitors (p<0.05). Knockdown of TBC1D24 inhibited the expression of IGF1R, PI3K, and p-AKT (p<0.05). Knockdown of TBC1D24 abolished tumorigenicity of MCF-7 cells. The average volume and weight of tumors was lower after silencing TBC1D24 expression (P<0.05). CONCLUSIONS Silencing TBC1D24 inhibited MCF-7 cells growth in vitro and in vivo. TBC1D24 promoted breast carcinoma growth through the IGF1R/PI3K/AKT pathway. TBC1D24 is a potential therapeutic target for breast cancer.
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Affiliation(s)
- Xiusheng Qu
- Department of Radiotherapy and Chemotherapy, First Affiliated Hospital of Jiamusi University, Jiamusi, Heilongjiang, China (mainland)
| | - Bin Zhao
- Department of Anus and Intestine Surgery, First Affiliated Hospital of Jiamusi University, Jiamusi, Heilongjiang, China (mainland)
| | - Min Hu
- Department of General Surgery, First Affiliated Hospital of Jiamusi University, Jiamusi, Heilongjiang, China (mainland)
| | - Zhiwu Ji
- Department of Anus and Intestine Surgery, Affiliated Hospital of Jiamusi University, Jiamusi, Heilongjiang, China (mainland)
| | - Jian Xu
- Department of General Surgery, First Affiliated Hospital of Jiamusi University, Jiamusi, Heilongjiang, China (mainland)
| | - Weibin Xia
- Department of General Surgery, First Affiliated Hospital of Jiamusi University, Jiamusi, Heilongjiang, China (mainland)
| | - Yikun Qu
- Department of General Surgery, First Affiliated Hospital of Jiamusi University, Jiamusi, Heilongjiang, China (mainland)
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30
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Abstract
Neonatal epilepsy genetics is a rapidly expanding field with recent technological advances in genomics leading to an expanding list of genetic disorders associated with neonatal-onset epilepsy. The genetic causes of neonatal epilepsy can be grouped into the following categories: (i) malformations of cortical development, (ii) genetic-metabolic, (iii) genetic-vascular, (iv) genetic-syndromic, and (v) genetic-cellular. Clinically, epilepsy in the neonate shows phenotypic overlap with pathogenic variants in unrelated genes causing similar clinical presentation (locus heterogeneity) and variants in the same gene leading to a wide clinical spectrum ranging from benign familial neonatal seizures to more severe epileptic encephalopathies (variable expressivity). We suggest a diagnostic approach to obtaining a genetic diagnosis with emphasis on clinical features such as electro-clinical phenotype and magnetic resonance imaging findings. Rapid identification of genetic disorders with targeted treatments should be a clinical priority. Achieving a genetic diagnosis can be challenging in a rapidly changing genetic landscape, but is increasingly possible.
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31
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Duan H, Peng J, Kessi M, Yin F. De Novo KCNQ2 Mutation in One Case of Epilepsy of Infancy With Migrating Focal Seizures That Evolved to Infantile Spasms. Child Neurol Open 2018; 5:2329048X18767738. [PMID: 29687029 PMCID: PMC5900813 DOI: 10.1177/2329048x18767738] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 01/02/2018] [Accepted: 02/21/2018] [Indexed: 11/29/2022] Open
Abstract
Epilepsy of infancy with migrating focal seizures (EIMFS) is a rare type of early-onset epileptic encephalopathy that is characterized by refractory migratory multifocal seizures that migrate between hemispheres. Its etiology is not well known although it is postulated to occur due to channelopathy. The authors report the first case of EIMFS due to a de novo heterozygous mutation in exon 4(c.881C>T missense mutation, p.Ala294Val, NM_172107.2) in KCNQ2 gene which later evolved into infantile spasms. However, it is the second case of EIMFS with KCNQ2 mutation. He presented with multifocal migratory partial seizures which started at the age of 8 days. Electroencephalogram examination revealed multifocal interictal spikes that migrated from one hemisphere to the other within a seizure. It was intractable with antiepileptic drugs and adrenocorticotropic hormone. He later developed spasms from the age of 8 months. Consequently, our case supports the new association between EIMFS and KCNQ2 mutations. Moreover, it enriches the disease phenotype because of transformation.
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Affiliation(s)
- Haolin Duan
- Department of Pediatrics, Xiang Ya Hospital, Central South University, Changsha, Hunan Province, China
| | - Jing Peng
- Department of Pediatrics, Xiang Ya Hospital, Central South University, Changsha, Hunan Province, China
| | - Miriam Kessi
- Department of Pediatrics, Xiang Ya Hospital, Central South University, Changsha, Hunan Province, China
| | - Fei Yin
- Department of Pediatrics, Xiang Ya Hospital, Central South University, Changsha, Hunan Province, China
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32
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Saito T, Ishii A, Sugai K, Sasaki M, Hirose S. A de novo missense mutation inSLC12A5found in a compound heterozygote patient with epilepsy of infancy with migrating focal seizures. Clin Genet 2017; 92:654-658. [DOI: 10.1111/cge.13049] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 04/29/2017] [Accepted: 05/02/2017] [Indexed: 02/04/2023]
Affiliation(s)
- T. Saito
- Department of Child Neurology, National Center Hospital; National Center of Neurology and Psychiatry; Tokyo Japan
| | - A. Ishii
- Department of Pediatrics, School of Medicine; Fukuoka University; Fukuoka Japan
| | - K. Sugai
- Department of Child Neurology, National Center Hospital; National Center of Neurology and Psychiatry; Tokyo Japan
| | - M. Sasaki
- Department of Child Neurology, National Center Hospital; National Center of Neurology and Psychiatry; Tokyo Japan
| | - S. Hirose
- Department of Pediatrics, School of Medicine; Fukuoka University; Fukuoka Japan
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33
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지나리, Se Hee Kim, 이준수, 강훈철, 이승태, Choi Jong Rak, 고아라, 김흥동. Quinidine Trial in a Patient with Epilepsy of Infancy with Migrating Focal Seizure and KCNT1 Mutation. ACTA ACUST UNITED AC 2017. [DOI: 10.26815/jkcns.2017.25.3.169] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Finelli MJ, Oliver PL. TLDc proteins: new players in the oxidative stress response and neurological disease. Mamm Genome 2017; 28:395-406. [PMID: 28707022 PMCID: PMC5614904 DOI: 10.1007/s00335-017-9706-7] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 07/03/2017] [Indexed: 12/14/2022]
Abstract
Oxidative stress (OS) arises from an imbalance in the cellular redox state, which can lead to intracellular damage and ultimately cell death. OS occurs as a result of normal ageing, but it is also implicated as a common etiological factor in neurological disease; thus identifying novel proteins that modulate the OS response may facilitate the design of new therapeutic approaches applicable to many disorders. In this review, we describe the recent progress that has been made using a range of genetic approaches to understand a family of proteins that share the highly conserved TLDc domain. We highlight their shared ability to prevent OS-related cell death and their unique functional characteristics, as well as discussing their potential application as new neuroprotective factors. Furthermore, with an increasing number of pathogenic mutations leading to epilepsy and hearing loss being discovered in the TLDc protein TBC1D24, understanding the function of this family has important implications for a range of inherited neurological diseases.
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Affiliation(s)
- Mattéa J Finelli
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford, OX1 3PT, UK
| | - Peter L Oliver
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford, OX1 3PT, UK.
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35
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Rehman AU, Friedman TB, Griffith AJ. Unresolved questions regarding human hereditary deafness. Oral Dis 2017; 23:551-558. [PMID: 27259978 PMCID: PMC5136515 DOI: 10.1111/odi.12516] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 05/27/2016] [Accepted: 05/30/2016] [Indexed: 01/18/2023]
Abstract
Human hearing loss is a common neurosensory disorder about which many basic research and clinically relevant questions are unresolved. This review on hereditary deafness focuses on three examples considered at first glance to be uncomplicated, however, upon inspection, are enigmatic and ripe for future research efforts. The three examples of clinical and genetic complexities are drawn from studies of (i) Pendred syndrome/DFNB4 (PDS, OMIM 274600), (ii) Perrault syndrome (deafness and infertility) due to mutations of CLPP (PRTLS3, OMIM 614129), and (iii) the unexplained extensive clinical variability associated with TBC1D24 mutations. At present, it is unknown how different mutations of TBC1D24 cause non-syndromic deafness (DFNB86, OMIM 614617), epilepsy (OMIM 605021), epilepsy with deafness, or DOORS syndrome (OMIM 220500) that is characterized by deafness, onychodystrophy (alteration of toenail or fingernail morphology), osteodystrophy (defective development of bone), mental retardation, and seizures. A comprehensive understanding of the multifaceted roles of each gene associated with human deafness is expected to provide future opportunities for restoration as well as preservation of normal hearing.
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Affiliation(s)
- A U Rehman
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | - T B Friedman
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | - A J Griffith
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
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Abstract
Stiripentol is a structurally unique antiepileptic drug that has several possible mechanisms of action, including diverse effects on the gamma-aminobutyric acid (GABA)-A receptor and novel inhibition of lactate dehydrogenase. Because of its inhibition of several cytochrome P450 enzymes, it has extensive pharmacokinetic interactions, which often necessitates reduction in doses of certain co-therapies, particularly clobazam. Stiripentol also has a neuroprotective action, by reducing calcium-mediated neurotoxicity. Evidence of its efficacy is most robust for Dravet syndrome, where stiripentol added to clobazam and valproic acid reduces seizure frequency and severity in the majority of cases. Small case series have also suggested benefit for malignant migrating partial seizures in infancy, super-refractory status epilepticus, and intractable focal epilepsy, although larger prospective studies are needed in these disorders.
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Affiliation(s)
- Katherine C Nickels
- Divisions of Child and Adolescent Neurology and Epilepsy, Department of Neurology, Mayo Clinic, 200 First St SW, Rochester, MN, 55905, USA
| | - Elaine C Wirrell
- Divisions of Child and Adolescent Neurology and Epilepsy, Department of Neurology, Mayo Clinic, 200 First St SW, Rochester, MN, 55905, USA.
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37
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Ngoh A, Bras J, Guerreiro R, McTague A, Ng J, Meyer E, Chong WK, Boyd S, MacLellan L, Kirkpatrick M, Kurian MA. TBC1D24 Mutations in a Sibship with Multifocal Polymyoclonus. TREMOR AND OTHER HYPERKINETIC MOVEMENTS (NEW YORK, N.Y.) 2017; 7:452. [PMID: 28428906 PMCID: PMC5395678 DOI: 10.7916/d8q52vbv] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 03/16/2017] [Indexed: 01/02/2023]
Abstract
Background Advances in molecular genetic technologies have improved our understanding of genetic causes of rare neurological disorders with features of myoclonus. Case Report A family with two affected siblings, presenting with multifocal polymyoclonus and neurodevelopmental delay, was recruited for whole-exome sequencing following unyielding diagnostic neurometabolic investigations. Compound heterozygous mutations in TBC1D24, a gene previously associated with various epilepsy phenotypes and hearing loss, were identified in both siblings. The mutations included a missense change c.457G>A (p.Glu157Lys), and a novel frameshift mutation c.545del (p.Thr182Serfs*6). Discussion We propose that TBC1D24-related diseases should be in the differential diagnosis for children with polymyoclonus.
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Affiliation(s)
- Adeline Ngoh
- Neurosciences Unit, University College London, Institute of Child Health, London, UK.,Department of Neurology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Jose Bras
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK.,Department of Medical Sciences and Institute of Biomedicine - iBiMED, University of Aveiro, Aveiro, Portugal
| | - Rita Guerreiro
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK.,Department of Medical Sciences and Institute of Biomedicine - iBiMED, University of Aveiro, Aveiro, Portugal
| | - Amy McTague
- Neurosciences Unit, University College London, Institute of Child Health, London, UK.,Department of Neurology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Joanne Ng
- Neurosciences Unit, University College London, Institute of Child Health, London, UK.,Department of Neurology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Esther Meyer
- Neurosciences Unit, University College London, Institute of Child Health, London, UK
| | - W Kling Chong
- Department of Neuroradiology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Stewart Boyd
- Department of Neurophysiology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | | | | | - Manju A Kurian
- Neurosciences Unit, University College London, Institute of Child Health, London, UK.,Department of Neurology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
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38
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Sheehan P, Waites CL. Coordination of synaptic vesicle trafficking and turnover by the Rab35 signaling network. Small GTPases 2017; 10:54-63. [PMID: 28129039 PMCID: PMC6343537 DOI: 10.1080/21541248.2016.1270392] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Rab35 and the Rab35 network of GAPs, GEFs, and effectors are important regulators of membrane trafficking for a variety of cellular processes, from cytokinesis and phagocytosis to neurite outgrowth. In the past five years, components of this signaling network have also been implicated as critical mediators of synaptic vesicle (SV) recycling and protein homeostasis. Recent studies by several groups, including our own, have demonstrated that Rab35-mediated endosomal sorting is required for the degradation of SV proteins via the ESCRT pathway, thereby eliminating old or damaged proteins from the SV pool. This sorting process is regulated by Rab35 activation in response to neuronal activity, and potentially by an antagonistic signaling relationship between Rab35 and the small GTPase Arf6 that directs SVs into distinct recycling pathways depending on neuronal activity levels. Furthermore, mutations in genes encoding Rab35 regulatory proteins are emerging as causative factors in human neurologic and neurodegenerative diseases, consistent with their important roles in synaptic and neuronal health. Here, we review these recent findings and offer our perspective on how the Rab35 signaling network functions to maintain neurotransmission and synaptic fitness.
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Affiliation(s)
- Patricia Sheehan
- a Department of Pathology and Cell Biology , Columbia University Medical Center , New York , NY , USA
| | - Clarissa L Waites
- a Department of Pathology and Cell Biology , Columbia University Medical Center , New York , NY , USA.,b Department of Neuroscience , Columbia University Medical Center , New York , NY , USA
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Fischer B, Lüthy K, Paesmans J, De Koninck C, Maes I, Swerts J, Kuenen S, Uytterhoeven V, Verstreken P, Versées W. Skywalker-TBC1D24 has a lipid-binding pocket mutated in epilepsy and required for synaptic function. Nat Struct Mol Biol 2016; 23:965-973. [DOI: 10.1038/nsmb.3297] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 08/25/2016] [Indexed: 01/08/2023]
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Lozano R, Herman K, Rothfuss M, Rieger H, Bayrak-Toydemir P, Aprile D, Fruscione F, Zara F, Fassio A. Clinical intrafamilial variability in lethal familial neonatal seizure disorder caused by TBC1D24 mutations. Am J Med Genet A 2016; 170:3207-3214. [DOI: 10.1002/ajmg.a.37933] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 07/30/2016] [Indexed: 11/10/2022]
Affiliation(s)
- Reymundo Lozano
- Departments of Genetic and Genomic Sciences, Psychiatry, and Pediatrics; Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai; New York New York
| | - Kristin Herman
- Department of Pediatrics; UC Davis Medical Center; Medical Investigation of Neurodevelopmental Disorders (MIND) Institute; Sacramento California
| | - Melanie Rothfuss
- Department of Pediatrics; UC Davis Medical Center; Medical Investigation of Neurodevelopmental Disorders (MIND) Institute; Sacramento California
| | - Hillary Rieger
- Departments of Genetic and Genomic Sciences, Psychiatry, and Pediatrics; Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai; New York New York
| | | | - Davide Aprile
- Department of Experimental Medicine; University of Genova; Genova Italy
| | - Floriana Fruscione
- Laboratory of Neurogenetics and Neuroscience; G. Gaslini Institute; Genova Italy
| | - Federico Zara
- Laboratory of Neurogenetics and Neuroscience; G. Gaslini Institute; Genova Italy
| | - Anna Fassio
- Department of Experimental Medicine; University of Genova; Genova Italy
- Center of Synaptic Neuroscience and Technology; Fondazione Istituto Italiano di Tecnologia; Genova Italy
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Saitsu H, Watanabe M, Akita T, Ohba C, Sugai K, Ong WP, Shiraishi H, Yuasa S, Matsumoto H, Beng KT, Saitoh S, Miyatake S, Nakashima M, Miyake N, Kato M, Fukuda A, Matsumoto N. Impaired neuronal KCC2 function by biallelic SLC12A5 mutations in migrating focal seizures and severe developmental delay. Sci Rep 2016; 6:30072. [PMID: 27436767 PMCID: PMC4951812 DOI: 10.1038/srep30072] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2016] [Accepted: 06/28/2016] [Indexed: 11/09/2022] Open
Abstract
Epilepsy of infancy with migrating focal seizures (EIMFS) is one of the early-onset epileptic syndromes characterized by migrating polymorphous focal seizures. Whole exome sequencing (WES) in ten sporadic and one familial case of EIMFS revealed compound heterozygous SLC12A5 (encoding the neuronal K(+)-Cl(-) co-transporter KCC2) mutations in two families: c.279 + 1G > C causing skipping of exon 3 in the transcript (p.E50_Q93del) and c.572 C >T (p.A191V) in individuals 1 and 2, and c.967T > C (p.S323P) and c.1243 A > G (p.M415V) in individual 3. Another patient (individual 4) with migrating multifocal seizures and compound heterozygous mutations [c.953G > C (p.W318S) and c.2242_2244del (p.S748del)] was identified by searching WES data from 526 patients and SLC12A5-targeted resequencing data from 141 patients with infantile epilepsy. Gramicidin-perforated patch-clamp analysis demonstrated strongly suppressed Cl(-) extrusion function of E50_Q93del and M415V mutants, with mildly impaired function of A191V and S323P mutants. Cell surface expression levels of these KCC2 mutants were similar to wildtype KCC2. Heterologous expression of two KCC2 mutants, mimicking the patient status, produced a significantly greater intracellular Cl(-) level than with wildtype KCC2, but less than without KCC2. These data clearly demonstrated that partially disrupted neuronal Cl(-) extrusion, mediated by two types of differentially impaired KCC2 mutant in an individual, causes EIMFS.
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Affiliation(s)
- Hirotomo Saitsu
- Department of Human Genetics, Graduate School of Medicine, Yokohama City University, 3-9 Fukuura, Yokohama 236-0004, Japan
| | - Miho Watanabe
- Department of Neurophysiology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Hamamatsu 431-3192, Japan
| | - Tenpei Akita
- Department of Neurophysiology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Hamamatsu 431-3192, Japan
| | - Chihiro Ohba
- Department of Human Genetics, Graduate School of Medicine, Yokohama City University, 3-9 Fukuura, Yokohama 236-0004, Japan
| | - Kenji Sugai
- Department of Child Neurology, National Center Hospital, National Center of Neurology and Psychiatry, 4-1-1 Ogawahigashi-cho, Kodaira, Tokyo 187-8551, Japan
| | - Winnie Peitee Ong
- Department of Genetics, Hospital Kuala Lumpur, Jalan Pahang, Kuala Lumpur 50586, Malaysia
| | - Hideaki Shiraishi
- Department of Pediatrics, Hokkaido University Graduate School of Medicine, North 15 West 7, Sapporo 060-8638, Japan
| | - Shota Yuasa
- Department of Child Neurology, National Center Hospital, National Center of Neurology and Psychiatry, 4-1-1 Ogawahigashi-cho, Kodaira, Tokyo 187-8551, Japan
| | - Hiroshi Matsumoto
- Department of Pediatrics, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan
| | - Khoo Teik Beng
- Department of Pediatrics, Institute of Pediatrics, Hospital Kuala Lumpur, Jalan Pahang, Kuala Lumpur 50586, Malaysia
| | - Shinji Saitoh
- Department of Pediatrics and Neonatology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-Cho, Nagoya 467-8601, Japan
| | - Satoko Miyatake
- Department of Human Genetics, Graduate School of Medicine, Yokohama City University, 3-9 Fukuura, Yokohama 236-0004, Japan
| | - Mitsuko Nakashima
- Department of Human Genetics, Graduate School of Medicine, Yokohama City University, 3-9 Fukuura, Yokohama 236-0004, Japan
| | - Noriko Miyake
- Department of Human Genetics, Graduate School of Medicine, Yokohama City University, 3-9 Fukuura, Yokohama 236-0004, Japan
| | - Mitsuhiro Kato
- Department of Pediatrics, Showa University School of Medicine, 1-5-8 Hatanodai, Tokyo 142-8666, Japan
| | - Atsuo Fukuda
- Department of Neurophysiology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Hamamatsu 431-3192, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Graduate School of Medicine, Yokohama City University, 3-9 Fukuura, Yokohama 236-0004, Japan
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Balestrini S, Milh M, Castiglioni C, Lüthy K, Finelli MJ, Verstreken P, Cardon A, Stražišar BG, Holder JL, Lesca G, Mancardi MM, Poulat AL, Repetto GM, Banka S, Bilo L, Birkeland LE, Bosch F, Brockmann K, Cross JH, Doummar D, Félix TM, Giuliano F, Hori M, Hüning I, Kayserili H, Kini U, Lees MM, Meenakshi G, Mewasingh L, Pagnamenta AT, Peluso S, Mey A, Rice GM, Rosenfeld JA, Taylor JC, Troester MM, Stanley CM, Ville D, Walkiewicz M, Falace A, Fassio A, Lemke JR, Biskup S, Tardif J, Ajeawung NF, Tolun A, Corbett M, Gecz J, Afawi Z, Howell KB, Oliver KL, Berkovic SF, Scheffer IE, de Falco FA, Oliver PL, Striano P, Zara F, Campeau PM, Sisodiya SM. TBC1D24 genotype-phenotype correlation: Epilepsies and other neurologic features. Neurology 2016; 87:77-85. [PMID: 27281533 PMCID: PMC4932231 DOI: 10.1212/wnl.0000000000002807] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 03/28/2016] [Indexed: 11/15/2022] Open
Abstract
Objective: To evaluate the phenotypic spectrum associated with mutations in TBC1D24. Methods: We acquired new clinical, EEG, and neuroimaging data of 11 previously unreported and 37 published patients. TBC1D24 mutations, identified through various sequencing methods, can be found online (http://lovd.nl/TBC1D24). Results: Forty-eight patients were included (28 men, 20 women, average age 21 years) from 30 independent families. Eighteen patients (38%) had myoclonic epilepsies. The other patients carried diagnoses of focal (25%), multifocal (2%), generalized (4%), and unclassified epilepsy (6%), and early-onset epileptic encephalopathy (25%). Most patients had drug-resistant epilepsy. We detail EEG, neuroimaging, developmental, and cognitive features, treatment responsiveness, and physical examination. In silico evaluation revealed 7 different highly conserved motifs, with the most common pathogenic mutation located in the first. Neuronal outgrowth assays showed that some TBC1D24 mutations, associated with the most severe TBC1D24-associated disorders, are not necessarily the most disruptive to this gene function. Conclusions: TBC1D24-related epilepsy syndromes show marked phenotypic pleiotropy, with multisystem involvement and severity spectrum ranging from isolated deafness (not studied here), benign myoclonic epilepsy restricted to childhood with complete seizure control and normal intellect, to early-onset epileptic encephalopathy with severe developmental delay and early death. There is no distinct correlation with mutation type or location yet, but patterns are emerging. Given the phenotypic breadth observed, TBC1D24 mutation screening is indicated in a wide variety of epilepsies. A TBC1D24 consortium was formed to develop further research on this gene and its associated phenotypes.
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Characteristic Features of the Interictal EEG Background in 2 Patients With Malignant Migrating Partial Epilepsy in Infancy. J Clin Neurophysiol 2016; 32:e23-9. [PMID: 25839129 DOI: 10.1097/wnp.0000000000000178] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
PURPOSE To describe chronological electrographic features of the interictal EEG background observed in two patients with malignant migrating partial epilepsy in infancy from neonatal to early infantile period. METHODS EEGs of two patients who fulfilled diagnostic criteria for malignant migrating partial epilepsy in infancy were acquired over the period of 6 months to monitor treatment efficacy and characterize seizures and other paroxysmal events. RESULTS Both patients followed a similar sequential pattern. A distinctive evolution from a dysmature term neonatal EEG pattern to an asynchronous suppression burst pattern was observed before the interictal background becoming continuous. CONCLUSIONS Physicians providing care to infants with intractable epilepsy and burst suppression EEG pattern should be alert to the possibility of malignant migrating partial epilepsy in infancy. An earlier diagnosis of malignant migrating partial epilepsy in infancy would help to guide diagnostic workup including genetic testing.
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Abstract
While genetic causes of epilepsy have been hypothesized from the time of Hippocrates, the advent of new genetic technologies has played a tremendous role in elucidating a growing number of specific genetic causes for the epilepsies. This progress has contributed vastly to our recognition of the epilepsies as a diverse group of disorders, the genetic mechanisms of which are heterogeneous. Genotype-phenotype correlation, however, is not always clear. Nonetheless, the developments in genetic diagnosis raise the promise of a future of personalized medicine. Multiple genetic tests are now available, but there is no one test for all possible genetic mutations, and the balance between cost and benefit must be weighed. A genetic diagnosis, however, can provide valuable information regarding comorbidities, prognosis, and even treatment, as well as allow for genetic counseling. In this review, we will discuss the genetic mechanisms of the epilepsies as well as the specifics of particular genetic epilepsy syndromes. We will include an overview of the available genetic testing methods, the application of clinical knowledge into the selection of genetic testing, genotype-phenotype correlations of epileptic disorders, and therapeutic advances as well as a discussion of the importance of genetic counseling.
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Affiliation(s)
- Christelle M El Achkar
- Division of Epilepsy, Department of Neurology, Boston Children's Hospital, and Harvard Medical School, Fegan 9, 300 Longwood Ave, Boston, MA, 02115, USA,
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Finelli MJ, Sanchez-Pulido L, Liu KX, Davies KE, Oliver PL. The Evolutionarily Conserved Tre2/Bub2/Cdc16 (TBC), Lysin Motif (LysM), Domain Catalytic (TLDc) Domain Is Neuroprotective against Oxidative Stress. J Biol Chem 2016; 291:2751-63. [PMID: 26668325 PMCID: PMC4742741 DOI: 10.1074/jbc.m115.685222] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 12/01/2015] [Indexed: 11/16/2022] Open
Abstract
Oxidative stress is a pathological feature of many neurological disorders; therefore, utilizing proteins that are protective against such cellular insults is a potentially valuable therapeutic approach. Oxidation resistance 1 (OXR1) has been shown previously to be critical for oxidative stress resistance in neuronal cells; deletion of this gene causes neurodegeneration in mice, yet conversely, overexpression of OXR1 is protective in cellular and mouse models of amyotrophic lateral sclerosis. However, the molecular mechanisms involved are unclear. OXR1 contains the Tre2/Bub2/Cdc16 (TBC), lysin motif (LysM), domain catalytic (TLDc) domain, a motif present in a family of proteins including TBC1 domain family member 24 (TBC1D24), a protein mutated in a range of disorders characterized by seizures, hearing loss, and neurodegeneration. The TLDc domain is highly conserved across species, although the structure-function relationship is unknown. To understand the role of this domain in the stress response, we carried out systematic analysis of all mammalian TLDc domain-containing proteins, investigating their expression and neuroprotective properties in parallel. In addition, we performed a detailed structural and functional study of this domain in which we identified key residues required for its activity. Finally, we present a new mouse insertional mutant of Oxr1, confirming that specific disruption of the TLDc domain in vivo is sufficient to cause neurodegeneration. Our data demonstrate that the integrity of the TLDc domain is essential for conferring neuroprotection, an important step in understanding the functional significance of all TLDc domain-containing proteins in the cellular stress response and disease.
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Affiliation(s)
- Mattéa J Finelli
- From the MRC Functional Genomics Unit, Department of Physiology, Anatomy, and Genetics, University of Oxford, Parks Road, Oxford OX1 3PT, United Kingdom
| | - Luis Sanchez-Pulido
- From the MRC Functional Genomics Unit, Department of Physiology, Anatomy, and Genetics, University of Oxford, Parks Road, Oxford OX1 3PT, United Kingdom
| | - Kevin X Liu
- From the MRC Functional Genomics Unit, Department of Physiology, Anatomy, and Genetics, University of Oxford, Parks Road, Oxford OX1 3PT, United Kingdom
| | - Kay E Davies
- From the MRC Functional Genomics Unit, Department of Physiology, Anatomy, and Genetics, University of Oxford, Parks Road, Oxford OX1 3PT, United Kingdom
| | - Peter L Oliver
- From the MRC Functional Genomics Unit, Department of Physiology, Anatomy, and Genetics, University of Oxford, Parks Road, Oxford OX1 3PT, United Kingdom
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Characterization of two de novoKCNT1 mutations in children with malignant migrating partial seizures in infancy. Mol Cell Neurosci 2016; 72:54-63. [PMID: 26784557 DOI: 10.1016/j.mcn.2016.01.004] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 12/06/2015] [Accepted: 01/15/2016] [Indexed: 01/08/2023] Open
Abstract
The KCNT1 gene encodes for subunits contributing to the Na(+)-activated K(+) current (KNa), expressed in many cell types. Mutations in KCNT1 have been found in patients affected with a wide spectrum of early-onset epilepsies, including Malignant Migrating Partial Seizures in Infancy (MMPSI), a severe early-onset epileptic encephalopathy characterized by pharmacoresistant focal seizures migrating from one brain region or hemisphere to another and neurodevelopment arrest or regression, resulting in profound disability. In the present study we report identification by whole exome sequencing (WES) of two de novo, heterozygous KCNT1 mutations (G288S and, not previously reported, M516V) in two unrelated MMPSI probands. Functional studies in a heterologous expression system revealed that channels formed by mutant KCNT1 subunits carried larger currents when compared to wild-type KCNT1 channels, both as homo- and heteromers with these last. Both mutations induced a marked leftward shift in homomeric channel activation gating. Interestingly, the KCNT1 blockers quinidine (3-1000μM) and bepridil (0.03-10μM) inhibited both wild-type and mutant KCNT1 currents in a concentration-dependent manner, with mutant channels showing higher sensitivity to blockade. This latter result suggests two genotype-tailored pharmacological strategies to specifically counteract the dysfunction of KCNT1 activating mutations in MMPSI patients.
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Lim CX, Ricos MG, Dibbens LM, Heron SE. KCNT1mutations in seizure disorders: the phenotypic spectrum and functional effects. J Med Genet 2016; 53:217-25. [DOI: 10.1136/jmedgenet-2015-103508] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 12/06/2015] [Indexed: 01/01/2023]
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48
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Myers C, Mefford H. Genetic investigations of the epileptic encephalopathies. PROGRESS IN BRAIN RESEARCH 2016; 226:35-60. [DOI: 10.1016/bs.pbr.2016.04.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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49
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Hardies K, Weckhuysen S, De Jonghe P, Suls A. Lessons learned from gene identification studies in Mendelian epilepsy disorders. Eur J Hum Genet 2015; 24:961-7. [PMID: 26603999 DOI: 10.1038/ejhg.2015.251] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 10/05/2015] [Accepted: 10/29/2015] [Indexed: 01/23/2023] Open
Abstract
Next-generation sequencing (NGS) technologies are now routinely used for gene identification in Mendelian disorders. Setting up cost-efficient NGS projects and managing the large amount of variants remains, however, a challenging job. Here we provide insights in the decision-making processes before and after the use of NGS in gene identification studies. Genetic factors are thought to have a role in ~70% of all epilepsies, and a variety of inheritance patterns have been described for seizure-associated gene defects. We therefore chose epilepsy as disease model and selected 35 NGS studies that focused on patients with a Mendelian epilepsy disorder. The strategies used for gene identification and their respective outcomes were reviewed. High-throughput NGS strategies have led to the identification of several new epilepsy-causing genes, enlarging our knowledge on both known and novel pathomechanisms. NGS findings have furthermore extended the awareness of phenotypical and genetic heterogeneity. By discussing recent studies we illustrate: (I) the power of NGS for gene identification in Mendelian disorders, (II) the accelerating pace in which this field evolves, and (III) the considerations that have to be made when performing NGS studies. Nonetheless, the enormous rise in gene discovery over the last decade, many patients and families included in gene identification studies still remain without a molecular diagnosis; hence, further genetic research is warranted. On the basis of successful NGS studies in epilepsy, we discuss general approaches to guide human geneticists and clinicians in setting up cost-efficient gene identification NGS studies.
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Affiliation(s)
- Katia Hardies
- VIB-Department of Molecular Genetics, Neurogenetics Group, University of Antwerp, Antwerp, Belgium.,Laboratory of Neurogenetics, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium
| | - Sarah Weckhuysen
- VIB-Department of Molecular Genetics, Neurogenetics Group, University of Antwerp, Antwerp, Belgium.,Laboratory of Neurogenetics, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium
| | - Peter De Jonghe
- VIB-Department of Molecular Genetics, Neurogenetics Group, University of Antwerp, Antwerp, Belgium.,Laboratory of Neurogenetics, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium.,Division of Neurology, Antwerp University Hospital, Antwerp, Belgium
| | - Arvid Suls
- VIB-Department of Molecular Genetics, Neurogenetics Group, University of Antwerp, Antwerp, Belgium.,Laboratory of Neurogenetics, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium
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Gonsales MC, Montenegro MA, Soler CV, Coan AC, Guerreiro MM, Lopes-Cendes I. Recent developments in the genetics of childhood epileptic encephalopathies: impact in clinical practice. ARQUIVOS DE NEURO-PSIQUIATRIA 2015; 73:946-58. [PMID: 26517219 DOI: 10.1590/0004-282x20150122] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 07/20/2015] [Indexed: 01/03/2023]
Abstract
Recent advances in molecular genetics led to the discovery of several genes for childhood epileptic encephalopathies (CEEs). As the knowledge about the genes associated with this group of disorders develops, it becomes evident that CEEs present a number of specific genetic characteristics, which will influence the use of molecular testing for clinical purposes. Among these, there are the presence of marked genetic heterogeneity and the high frequency of de novo mutations. Therefore, the main objectives of this review paper are to present and discuss current knowledge regarding i) new genetic findings in CEEs, ii) phenotype-genotype correlations in different forms of CEEs; and, most importantly, iii) the impact of these new findings in clinical practice. Accompanying this text we have included a comprehensive table, containing the list of genes currently known to be involved in the etiology of CEEs.
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Affiliation(s)
- Marina C Gonsales
- Instituto Brasileiro de Neurociências e Neurotecnologia, Faculdade de Ciências Médicas, Universidade de Campinas, Campinas, SP, Brazil
| | - Maria Augusta Montenegro
- Instituto Brasileiro de Neurociências e Neurotecnologia, Faculdade de Ciências Médicas, Universidade de Campinas, Campinas, SP, Brazil
| | - Camila V Soler
- Instituto Brasileiro de Neurociências e Neurotecnologia, Faculdade de Ciências Médicas, Universidade de Campinas, Campinas, SP, Brazil
| | - Ana Carolina Coan
- Instituto Brasileiro de Neurociências e Neurotecnologia, Faculdade de Ciências Médicas, Universidade de Campinas, Campinas, SP, Brazil
| | - Marilisa M Guerreiro
- Instituto Brasileiro de Neurociências e Neurotecnologia, Faculdade de Ciências Médicas, Universidade de Campinas, Campinas, SP, Brazil
| | - Iscia Lopes-Cendes
- Instituto Brasileiro de Neurociências e Neurotecnologia, Faculdade de Ciências Médicas, Universidade de Campinas, Campinas, SP, Brazil
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