1
|
Cheng J, Wang Z, Tang M, Zhang W, Li G, Tan S, Mu C, Hu M, Zhang D, Jia X, Wen Y, Guo H, Xu D, Liu L, Li J, Xia K, Li F, Duan R, Xu Z, Yuan L. KCTD10 regulates brain development by destabilizing brain disorder-associated protein KCTD13. Proc Natl Acad Sci U S A 2024; 121:e2315707121. [PMID: 38489388 PMCID: PMC10963008 DOI: 10.1073/pnas.2315707121] [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: 09/10/2023] [Accepted: 02/02/2024] [Indexed: 03/17/2024] Open
Abstract
KCTD10 belongs to the KCTD (potassiumchannel tetramerization domain) family, many members of which are associated with neuropsychiatric disorders. However, the biological function underlying the association with brain disorders remains to be explored. Here, we reveal that Kctd10 is highly expressed in neuronal progenitors and layer V neurons throughout brain development. Kctd10 deficiency triggers abnormal proliferation and differentiation of neuronal progenitors, reduced deep-layer (especially layer V) neurons, increased upper-layer neurons, and lowered brain size. Mechanistically, we screened and identified a unique KCTD10-interacting protein, KCTD13, associated with neurodevelopmental disorders. KCTD10 mediated the ubiquitination-dependent degradation of KCTD13 and KCTD10 ablation resulted in a considerable increase of KCTD13 expression in the developing cortex. KCTD13 overexpression in neuronal progenitors led to reduced proliferation and abnormal cell distribution, mirroring KCTD10 deficiency. Notably, mice with brain-specific Kctd10 knockout exhibited obvious motor deficits. This study uncovers the physiological function of KCTD10 and provides unique insights into the pathogenesis of neurodevelopmental disorders.
Collapse
Affiliation(s)
- Jianbo Cheng
- Center for Medical Genetics, Hunan Key Laboratory of Medical Genetics, Key Lab of Rare Pediatric Diseases of Ministry of Education, School of Life Sciences, Central South University, Changsha, Hunan410078, China
| | - Zhen Wang
- Center for Medical Genetics, Hunan Key Laboratory of Medical Genetics, Key Lab of Rare Pediatric Diseases of Ministry of Education, School of Life Sciences, Central South University, Changsha, Hunan410078, China
| | - Manpei Tang
- Center for Medical Genetics, Hunan Key Laboratory of Medical Genetics, Key Lab of Rare Pediatric Diseases of Ministry of Education, School of Life Sciences, Central South University, Changsha, Hunan410078, China
| | - Wen Zhang
- Center for Medical Genetics, Hunan Key Laboratory of Medical Genetics, Key Lab of Rare Pediatric Diseases of Ministry of Education, School of Life Sciences, Central South University, Changsha, Hunan410078, China
| | - Guozhong Li
- Center for Medical Genetics, Hunan Key Laboratory of Medical Genetics, Key Lab of Rare Pediatric Diseases of Ministry of Education, School of Life Sciences, Central South University, Changsha, Hunan410078, China
| | - Senwei Tan
- Center for Medical Genetics, Hunan Key Laboratory of Medical Genetics, Key Lab of Rare Pediatric Diseases of Ministry of Education, School of Life Sciences, Central South University, Changsha, Hunan410078, China
| | - Chenjun Mu
- Center for Medical Genetics, Hunan Key Laboratory of Medical Genetics, Key Lab of Rare Pediatric Diseases of Ministry of Education, School of Life Sciences, Central South University, Changsha, Hunan410078, China
| | - Mengyuan Hu
- Center for Medical Genetics, Hunan Key Laboratory of Medical Genetics, Key Lab of Rare Pediatric Diseases of Ministry of Education, School of Life Sciences, Central South University, Changsha, Hunan410078, China
| | - Dan Zhang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing100101, China
| | - Xiangbin Jia
- Center for Medical Genetics, Hunan Key Laboratory of Medical Genetics, Key Lab of Rare Pediatric Diseases of Ministry of Education, School of Life Sciences, Central South University, Changsha, Hunan410078, China
| | - Yangxuan Wen
- Center for Medical Genetics, Hunan Key Laboratory of Medical Genetics, Key Lab of Rare Pediatric Diseases of Ministry of Education, School of Life Sciences, Central South University, Changsha, Hunan410078, China
| | - Hui Guo
- Center for Medical Genetics, Hunan Key Laboratory of Medical Genetics, Key Lab of Rare Pediatric Diseases of Ministry of Education, School of Life Sciences, Central South University, Changsha, Hunan410078, China
- Hunan Key Laboratory of Animal Models for Human Diseases, Central South University, Changsha, Hunan410078, China
| | - Dan Xu
- Fujian Key Laboratory of Molecular Neurology, Institute of Neuroscience, Fujian Medical University, Fuzhou350005, China
| | - Liang Liu
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing100053, China
| | - Jiada Li
- Center for Medical Genetics, Hunan Key Laboratory of Medical Genetics, Key Lab of Rare Pediatric Diseases of Ministry of Education, School of Life Sciences, Central South University, Changsha, Hunan410078, China
- Hunan Key Laboratory of Animal Models for Human Diseases, Central South University, Changsha, Hunan410078, China
| | - Kun Xia
- Center for Medical Genetics, Hunan Key Laboratory of Medical Genetics, Key Lab of Rare Pediatric Diseases of Ministry of Education, School of Life Sciences, Central South University, Changsha, Hunan410078, China
- Hunan Key Laboratory of Animal Models for Human Diseases, Central South University, Changsha, Hunan410078, China
| | - Faxiang Li
- Center for Medical Genetics, Hunan Key Laboratory of Medical Genetics, Key Lab of Rare Pediatric Diseases of Ministry of Education, School of Life Sciences, Central South University, Changsha, Hunan410078, China
- Hunan Key Laboratory of Animal Models for Human Diseases, Central South University, Changsha, Hunan410078, China
| | - Ranhui Duan
- Center for Medical Genetics, Hunan Key Laboratory of Medical Genetics, Key Lab of Rare Pediatric Diseases of Ministry of Education, School of Life Sciences, Central South University, Changsha, Hunan410078, China
- Hunan Key Laboratory of Animal Models for Human Diseases, Central South University, Changsha, Hunan410078, China
| | - Zhiheng Xu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing100101, China
| | - Ling Yuan
- Center for Medical Genetics, Hunan Key Laboratory of Medical Genetics, Key Lab of Rare Pediatric Diseases of Ministry of Education, School of Life Sciences, Central South University, Changsha, Hunan410078, China
- Hunan Key Laboratory of Animal Models for Human Diseases, Central South University, Changsha, Hunan410078, China
| |
Collapse
|
2
|
Zimmern V, Minassian B. Progressive Myoclonus Epilepsy: A Scoping Review of Diagnostic, Phenotypic and Therapeutic Advances. Genes (Basel) 2024; 15:171. [PMID: 38397161 PMCID: PMC10888128 DOI: 10.3390/genes15020171] [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: 01/02/2024] [Revised: 01/23/2024] [Accepted: 01/26/2024] [Indexed: 02/25/2024] Open
Abstract
The progressive myoclonus epilepsies (PME) are a diverse group of disorders that feature both myoclonus and seizures that worsen gradually over a variable timeframe. While each of the disorders is individually rare, they collectively make up a non-trivial portion of the complex epilepsy and myoclonus cases that are seen in tertiary care centers. The last decade has seen substantial progress in our understanding of the pathophysiology, diagnosis, prognosis, and, in select disorders, therapies of these diseases. In this scoping review, we examine English language publications from the past decade that address diagnostic, phenotypic, and therapeutic advances in all PMEs. We then highlight the major lessons that have been learned and point out avenues for future investigation that seem promising.
Collapse
Affiliation(s)
- Vincent Zimmern
- Division of Child Neurology, University of Texas Southwestern, Dallas, TX 75390, USA;
| | | |
Collapse
|
3
|
Bernardi S, Gemignani F, Marchese M. The involvement of Purkinje cells in progressive myoclonic epilepsy: Focus on neuronal ceroid lipofuscinosis. Neurobiol Dis 2023; 185:106258. [PMID: 37573956 PMCID: PMC10480493 DOI: 10.1016/j.nbd.2023.106258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 08/01/2023] [Accepted: 08/11/2023] [Indexed: 08/15/2023] Open
Abstract
The progressive myoclonic epilepsies (PMEs) are a group of rare neurodegenerative diseases characterized by myoclonus, epileptic seizures, and progressive neurological deterioration with cerebellar involvement. They include storage diseases like Gaucher disease, Lafora disease, and forms of neuronal ceroid lipofuscinosis (NCL). To date, 13 NCLs have been reported (CLN1-CLN8, CLN10-CLN14), associated with mutations in different genes. These forms, which affect both children and adults, are characterized by seizures, cognitive and motor impairments, and in most cases visual loss. In NCLs, as in other PMEs, central nervous system (CNS) neurodegeneration is widespread and involves different subpopulations of neurons. One of the most affected regions is the cerebellar cortex, where motor and non-motor information is processed and transmitted to deep cerebellar nuclei through the axons of Purkinje cells (PCs). PCs, being GABAergic, have an inhibitory effect on their target neurons, and provide the only inhibitory output of the cerebellum. Degeneration of PCs has been linked to motor impairments and epileptic seizures. Seizures occur when some insult upsets the normal balance in the CNS between excitatory and inhibitory impulses, causing hyperexcitability. Here we review the role of PCs in epilepsy onset and progression following their PME-related loss. In particular, we focus on the involvement of PCs in seizure phenotype in NCLs, highlighting findings from case reports and studies of animal models in which epilepsy can be linked to PC loss.
Collapse
Affiliation(s)
- Sara Bernardi
- Department Neurobiology and Molecular Medicine, IRCCS Fondazione Stella Maris, 56128 Pisa, Italy; Department of Biology, University of Pisa, Pisa, Italy
| | | | - Maria Marchese
- Department Neurobiology and Molecular Medicine, IRCCS Fondazione Stella Maris, 56128 Pisa, Italy.
| |
Collapse
|
4
|
Liang JH, Alevy J, Akhanov V, Seo R, Massey CA, Jiang D, Zhou J, Sillitoe RV, Noebels JL, Samuel MA. Kctd7 deficiency induces myoclonic seizures associated with Purkinje cell death and microvascular defects. Dis Model Mech 2022; 15:dmm049642. [PMID: 35972048 PMCID: PMC9509889 DOI: 10.1242/dmm.049642] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 07/29/2022] [Indexed: 01/27/2023] Open
Abstract
Mutations in the potassium channel tetramerization domain-containing 7 (KCTD7) gene are associated with a severe neurodegenerative phenotype characterized by childhood onset of progressive and intractable myoclonic seizures accompanied by developmental regression. KCTD7-driven disease is part of a large family of progressive myoclonic epilepsy syndromes displaying a broad spectrum of clinical severity. Animal models of KCTD7-related disease are lacking, and little is known regarding how KCTD7 protein defects lead to epilepsy and cognitive dysfunction. We characterized Kctd7 expression patterns in the mouse brain during development and show that it is selectively enriched in specific regions as the brain matures. We further demonstrate that Kctd7-deficient mice develop seizures and locomotor defects with features similar to those observed in human KCTD7-associated diseases. We also show that Kctd7 is required for Purkinje cell survival in the cerebellum and that selective degeneration of these neurons is accompanied by defects in cerebellar microvascular organization and patterning. Taken together, these results define a new model for KCTD7-associated epilepsy and identify Kctd7 as a modulator of neuron survival and excitability linked to microvascular alterations in vulnerable regions.
Collapse
Affiliation(s)
- Justine H. Liang
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jonathan Alevy
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030, USA
| | - Viktor Akhanov
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ryan Seo
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
- Developmental Neurogenetics Laboratory, Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Human and Molecular Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Cory A. Massey
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
- Developmental Neurogenetics Laboratory, Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Human and Molecular Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Danye Jiang
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030, USA
| | - Joy Zhou
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX 77030, USA
- Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, Houston, TX 77030, USA
| | - Roy V. Sillitoe
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX 77030, USA
- Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, Houston, TX 77030, USA
| | - Jeffrey L. Noebels
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
- Developmental Neurogenetics Laboratory, Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Human and Molecular Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Melanie A. Samuel
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030, USA
| |
Collapse
|
5
|
Binaafar S, Garshasbi M, Tavasoli AR, Badv RS, Hosseiny SMM, Samanta D, Rabbani B, Mahdieh N. Nonsyndromic Early-Onset Epileptic Encephalopathies: Two Novel KCTD7 Pathogenic Variants and a Literature Review. Dev Neurosci 2021; 43:348-357. [PMID: 34469883 DOI: 10.1159/000519318] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Accepted: 08/30/2021] [Indexed: 11/19/2022] Open
Abstract
Early-onset epileptic encephalopathies (EOEE) affect cognitive, sensory, and motor development. Genetic variations are among the identifiable primary causes of these syndromes. However, some patients have been reported to be affected by EOEE without any other clinical symptoms and signs. We study the genotype and phenotype of patients with nonsyndromic early-onset epileptic encephalopathy (NSEOEE) and report 2 novel patients from Iran. A comprehensive search was conducted in PubMed, John Willy, Springer, Elsevier, and Google Scholar databases to collect related information of all the previously reported cases with KCTD7 mutations. Fifty-four patients (from 40 families) were investigated. Using trio-whole-exome sequencing (trio-WES) and Sanger sequencing, the possible genetic causes of the disorder were checked. The probable impacts of the identified variants on the KCTD7 protein structure and function were predicted. This study provided a detailed overview of all published KCTD7 mutations and 2 de novo ones. We identified 2 novel homozygous variants of uncertain significance, c.458 G > A p. Arg153His and c.529C > T (p.Arg177Cys), in KCTD7 (NM_153033.4) (Chr7(GRCh37)). There is a significant wide distribution of the KCTD7 gene causing NSEOEE among different populations. In conclusion, KCTD7 mutations demonstrate a diverse geographical distribution alongside a wide range of ethnicities. This highlights the importance of careful consideration in the WES data analysis. Mutations of this gene may be a common cause of NSEOEE. Also, this study imprints targeted therapeutic opportunities for potassium channelepsies such as KCTD7-related NSEOEE.
Collapse
Affiliation(s)
- Sima Binaafar
- Growth and Development Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Masoud Garshasbi
- Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Ali Reza Tavasoli
- Myelin Disorders Clinic, Pediatric Neurology Division, Children's Medical Center, Pediatrics Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Reza Shervin Badv
- Children's Hospital Center, Pediatric Center of Excellence, Tehran University of Medical Center, Tehran, Iran
| | - Seyyed Mohammad Mahdi Hosseiny
- Myelin Disorders Clinic, Pediatric Neurology Division, Children's Medical Center, Pediatrics Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Debopam Samanta
- Child Neurology Section, Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Bahareh Rabbani
- Growth and Development Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Nejat Mahdieh
- Growth and Development Research Center, Tehran University of Medical Sciences, Tehran, Iran.,Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| |
Collapse
|
6
|
Burke EA, Sturgeon M, Zastrow DB, Fernandez L, Prybol C, Marwaha S, Frothingham EP, Ward PA, Eng CM, Fresard L, Montgomery SB, Enns GM, Fisher PG, Wolfe LA, Harding B, Carrington B, Bishop K, Sood R, Huang Y, Elkahloun A, Toro C, Bassuk AG, Wheeler MT, Markello TC, Gahl WA, Malicdan MCV. Compound heterozygous KCTD7 variants in progressive myoclonus epilepsy. J Neurogenet 2021; 35:74-83. [PMID: 33970744 DOI: 10.1080/01677063.2021.1892095] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
KCTD7 is a member of the potassium channel tetramerization domain-containing protein family and has been associated with progressive myoclonic epilepsy (PME), characterized by myoclonus, epilepsy, and neurological deterioration. Here we report four affected individuals from two unrelated families in which we identified KCTD7 compound heterozygous single nucleotide variants through exome sequencing. RNAseq was used to detect a non-annotated splicing junction created by a synonymous variant in the second family. Whole-cell patch-clamp analysis of neuroblastoma cells overexpressing the patients' variant alleles demonstrated aberrant potassium regulation. While all four patients experienced many of the common clinical features of PME, they also showed variable phenotypes not previously reported, including dysautonomia, brain pathology findings including a significantly reduced thalamus, and the lack of myoclonic seizures. To gain further insight into the pathogenesis of the disorder, zinc finger nucleases were used to generate kctd7 knockout zebrafish. Kctd7 homozygous mutants showed global dysregulation of gene expression and increased transcription of c-fos, which has previously been correlated with seizure activity in animal models. Together these findings expand the known phenotypic spectrum of KCTD7-associated PME, report a new animal model for future studies, and contribute valuable insights into the disease.
Collapse
Affiliation(s)
- Elizabeth A Burke
- NIH Undiagnosed Diseases Program, Common Fund, Office of the Director, NIH and National Human Genome Research Institute, NIH, Bethesda, MD, USA
| | - Morgan Sturgeon
- Department of Pediatrics, University of Iowa, Iowa City, IA, USA
| | - Diane B Zastrow
- Center for Undiagnosed Diseases, Stanford University School of Medicine, Stanford, CA, USA
| | - Liliana Fernandez
- Center for Undiagnosed Diseases, Stanford University School of Medicine, Stanford, CA, USA
| | - Cameron Prybol
- Center for Undiagnosed Diseases, Stanford University School of Medicine, Stanford, CA, USA
| | - Shruti Marwaha
- Center for Undiagnosed Diseases, Stanford University School of Medicine, Stanford, CA, USA
| | | | - Patricia A Ward
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Christine M Eng
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Laure Fresard
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA
| | - Stephen B Montgomery
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA.,Department of Genetics, Stanford University School of Medicine, Stanford, CA, USA
| | - Gregory M Enns
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, USA
| | - Paul G Fisher
- Center for Undiagnosed Diseases, Stanford University School of Medicine, Stanford, CA, USA.,Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, USA.,Department of Neurology, Stanford University School of Medicine, Stanford, CA, USA
| | - Lynne A Wolfe
- NIH Undiagnosed Diseases Program, Common Fund, Office of the Director, NIH and National Human Genome Research Institute, NIH, Bethesda, MD, USA
| | - Brian Harding
- Departments of Pathology and Lab Medicine (Neuropathology), Children's Hospital of Philadelphia and the Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Blake Carrington
- Zebrafish Core, Translational and Functional Genomics Branch, National Human Genome Research Institute, NIH, Bethesda, MD, USA
| | - Kevin Bishop
- Zebrafish Core, Translational and Functional Genomics Branch, National Human Genome Research Institute, NIH, Bethesda, MD, USA
| | - Raman Sood
- Zebrafish Core, Translational and Functional Genomics Branch, National Human Genome Research Institute, NIH, Bethesda, MD, USA
| | - Yan Huang
- NIH Undiagnosed Diseases Program, Common Fund, Office of the Director, NIH and National Human Genome Research Institute, NIH, Bethesda, MD, USA
| | - Abdel Elkahloun
- Microarray Core, Cancer Genetics and Comparative Genomics Branch, National Human Genome Research Institute, NIH, Bethesda, MD, USA
| | - Camilo Toro
- NIH Undiagnosed Diseases Program, Common Fund, Office of the Director, NIH and National Human Genome Research Institute, NIH, Bethesda, MD, USA
| | | | - Matthew T Wheeler
- Center for Undiagnosed Diseases, Stanford University School of Medicine, Stanford, CA, USA
| | - Thomas C Markello
- NIH Undiagnosed Diseases Program, Common Fund, Office of the Director, NIH and National Human Genome Research Institute, NIH, Bethesda, MD, USA
| | - William A Gahl
- NIH Undiagnosed Diseases Program, Common Fund, Office of the Director, NIH and National Human Genome Research Institute, NIH, Bethesda, MD, USA.,Medical Genetics Branch, National Human Genome Research Institute, NIH, Bethesda, MD, USA
| | - May Christine V Malicdan
- NIH Undiagnosed Diseases Program, Common Fund, Office of the Director, NIH and National Human Genome Research Institute, NIH, Bethesda, MD, USA
| |
Collapse
|
7
|
Dudipala SC, M P, Chennadi AK. A Novel Mutation in KCDT7 Gene in an Indian Girl With Progressive Myoclonus Epilepsy. Cureus 2021; 13:e13447. [PMID: 33767931 PMCID: PMC7982382 DOI: 10.7759/cureus.13447] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The progressive myoclonus epilepsy (PME) is a rare group of clinically and genetically heterogeneous disorders characterized by myoclonus, drug refractory epilepsy, and neurological deterioration. Here, we report a three-year-old female patient with neuroregression after a period of normal development and uncontrollable myoclonic seizures, which fulfill the criteria of PME. Next-generation sequencing revealed a novel homozygous mutation of variant c.173G>C in exon 2 of the KCDT7 (potassium channel tetramerization domain containing protein 7) gene that was compatible with the diagnosis of progressive myoclonic epilepsy 3 (PME3) with or without intracellular inclusions. This is a rare report of KCTD7 mutations causing PME in the Indian population. Our findings supported the important role of KCTD7 in PME and broadened the mutation spectrum.
Collapse
Affiliation(s)
- Sai Chandar Dudipala
- Pediatric Neurology, Star Women & Children Hospital, Karimnagar, IND.,Pediatrics, Prathima Institute of Medical Sciences, Karimnagar, IND
| | - Prashanthi M
- Pediatrics, Prathima Institute of Medical Sciences, Karimnagar, IND
| | | |
Collapse
|
8
|
Rossi M, van der Veen S, Merello M, Tijssen MAJ, van de Warrenburg B. Myoclonus-Ataxia Syndromes: A Diagnostic Approach. Mov Disord Clin Pract 2020; 8:9-24. [PMID: 33426154 DOI: 10.1002/mdc3.13106] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 09/30/2020] [Accepted: 10/14/2020] [Indexed: 12/30/2022] Open
Abstract
Background A myriad of disorders combine myoclonus and ataxia. Most causes are genetic and an increasing number of genes are being associated with myoclonus-ataxia syndromes (MAS), due to recent advances in genetic techniques. A proper etiologic diagnosis of MAS is clinically relevant, given the consequences for genetic counseling, treatment, and prognosis. Objectives To review the causes of MAS and to propose a diagnostic algorithm. Methods A comprehensive and structured literature search following PRISMA criteria was conducted to identify those disorders that may combine myoclonus with ataxia. Results A total of 135 causes of combined myoclonus and ataxia were identified, of which 30 were charted as the main causes of MAS. These include four acquired entities: opsoclonus-myoclonus-ataxia syndrome, celiac disease, multiple system atrophy, and sporadic prion diseases. The distinction between progressive myoclonus epilepsy and progressive myoclonus ataxia poses one of the main diagnostic dilemmas. Conclusions Diagnostic algorithms for pediatric and adult patients, based on clinical manifestations including epilepsy, are proposed to guide the differential diagnosis and corresponding work-up of the most important and frequent causes of MAS. A list of genes associated with MAS to guide genetic testing strategies is provided. Priority should be given to diagnose or exclude acquired or treatable disorders.
Collapse
Affiliation(s)
- Malco Rossi
- Movement Disorders Section Neuroscience Department Buenos Aires Argentina.,Argentine National Scientific and Technological Research Council (CONICET) Buenos Aires Argentina
| | - Sterre van der Veen
- Pontificia Universidad Católica Argentina (UCA) Buenos Aires Argentina.,Department of Neurology University of Groningen, University Medical Center Groningen Groningen The Netherlands
| | - Marcelo Merello
- Movement Disorders Section Neuroscience Department Buenos Aires Argentina.,Argentine National Scientific and Technological Research Council (CONICET) Buenos Aires Argentina.,Pontificia Universidad Católica Argentina (UCA) Buenos Aires Argentina
| | - Marina A J Tijssen
- Department of Neurology University of Groningen, University Medical Center Groningen Groningen The Netherlands.,Expertise Center Movement Disorders Groningen University Medical Center Groningen (UMCG) Groningen The Netherlands
| | - Bart van de Warrenburg
- Department of Neurology, Donders Institute for Brain, Cognition & Behaviour Radboud University Medical Center Nijmegen The Netherlands
| |
Collapse
|
9
|
Mastrangelo M, Sartori S, Simonati A, Brinciotti M, Moro F, Nosadini M, Pezzini F, Doccini S, Santorelli FM, Leuzzi V. Progressive myoclonus epilepsy and ceroidolipofuscinosis 14: The multifaceted phenotypic spectrum of KCTD7-related disorders. Eur J Med Genet 2019; 62:103591. [DOI: 10.1016/j.ejmg.2018.11.025] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 09/28/2018] [Accepted: 11/22/2018] [Indexed: 11/27/2022]
|
10
|
Menchini RJ, Chaudhry FA. Multifaceted regulation of the system A transporter Slc38a2 suggests nanoscale regulation of amino acid metabolism and cellular signaling. Neuropharmacology 2019; 161:107789. [PMID: 31574264 DOI: 10.1016/j.neuropharm.2019.107789] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 09/16/2019] [Accepted: 09/20/2019] [Indexed: 02/07/2023]
Abstract
Amino acids are essential for cellular protein synthesis, growth, metabolism, signaling and in stress responses. Cell plasma membranes harbor specialized transporters accumulating amino acids to support a variety of cellular biochemical pathways. Several transporters for neutral amino acids have been characterized. However, Slc38a2 (also known as SA1, SAT2, ATA2, SNAT2) representing the classical transport system A activity stands in a unique position: Being a secondarily active transporter energized by the electrochemical gradient of Na+, it creates steep concentration gradients for amino acids such as glutamine: this may subsequently drive the accumulation of additional neutral amino acids through exchange via transport systems ASC and L. Slc38a2 is ubiquitously expressed, yet in a cell-specific manner. In this review, we show that Slc38a2 is regulated at the transcriptional and translational levels as well as by ions and proteins through direct interactions. We describe how Slc38a2 senses amino acid availability and passes this onto intracellular signaling pathways and how it regulates protein synthesis, cellular proliferation and apoptosis through the mechanistic (mammalian) target of rapamycin (mTOR) and general control nonderepressible 2 (GCN2) pathways. Furthermore, we review how this extensively regulated transporter contributes to cellular osmoadaptation and how it is regulated by endoplasmic reticulum stress and various hormonal stimuli to promote cellular metabolism, cellular signaling and cell survival. This article is part of the issue entitled 'Special Issue on Neurotransmitter Transporters'.
Collapse
Affiliation(s)
| | - Farrukh Abbas Chaudhry
- Department of Molecular Medicine, University of Oslo, Oslo, Norway; Department of Plastic and Reconstructive Surgery, Oslo University Hospital, Oslo, Norway
| |
Collapse
|
11
|
Teng X, Aouacheria A, Lionnard L, Metz KA, Soane L, Kamiya A, Hardwick JM. KCTD: A new gene family involved in neurodevelopmental and neuropsychiatric disorders. CNS Neurosci Ther 2019; 25:887-902. [PMID: 31197948 PMCID: PMC6566181 DOI: 10.1111/cns.13156] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 05/02/2019] [Accepted: 05/13/2019] [Indexed: 12/12/2022] Open
Abstract
The underlying molecular basis for neurodevelopmental or neuropsychiatric disorders is not known. In contrast, mechanistic understanding of other brain disorders including neurodegeneration has advanced considerably. Yet, these do not approach the knowledge accrued for many cancers with precision therapeutics acting on well-characterized targets. Although the identification of genes responsible for neurodevelopmental and neuropsychiatric disorders remains a major obstacle, the few causally associated genes are ripe for discovery by focusing efforts to dissect their mechanisms. Here, we make a case for delving into mechanisms of the poorly characterized human KCTD gene family. Varying levels of evidence support their roles in neurocognitive disorders (KCTD3), neurodevelopmental disease (KCTD7), bipolar disorder (KCTD12), autism and schizophrenia (KCTD13), movement disorders (KCTD17), cancer (KCTD11), and obesity (KCTD15). Collective knowledge about these genes adds enhanced value, and critical insights into potential disease mechanisms have come from unexpected sources. Translation of basic research on the KCTD-related yeast protein Whi2 has revealed roles in nutrient signaling to mTORC1 (KCTD11) and an autophagy-lysosome pathway affecting mitochondria (KCTD7). Recent biochemical and structure-based studies (KCTD12, KCTD13, KCTD16) reveal mechanisms of regulating membrane channel activities through modulation of distinct GTPases. We explore how these seemingly varied functions may be disease related.
Collapse
Affiliation(s)
- Xinchen Teng
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and College of Pharmaceutical SciencesSoochow UniversitySuzhouChina
- W. Harry Feinstone Department of Molecular Microbiology and ImmunologyJohns Hopkins University Bloomberg School of Public HealthBaltimoreMaryland
| | - Abdel Aouacheria
- ISEM, Institut des Sciences de l'Evolution de Montpellier, CNRS, EPHE, IRDUniversité de MontpellierMontpellierFrance
| | - Loïc Lionnard
- ISEM, Institut des Sciences de l'Evolution de Montpellier, CNRS, EPHE, IRDUniversité de MontpellierMontpellierFrance
| | - Kyle A. Metz
- W. Harry Feinstone Department of Molecular Microbiology and ImmunologyJohns Hopkins University Bloomberg School of Public HealthBaltimoreMaryland
- Present address:
Feinberg School of MedicineNorthwestern UniversityChicagoUSA
| | - Lucian Soane
- W. Harry Feinstone Department of Molecular Microbiology and ImmunologyJohns Hopkins University Bloomberg School of Public HealthBaltimoreMaryland
| | - Atsushi Kamiya
- Department of Psychiatry and Behavioral SciencesJohns Hopkins School of MedicineBaltimoreMaryland
| | - J. Marie Hardwick
- W. Harry Feinstone Department of Molecular Microbiology and ImmunologyJohns Hopkins University Bloomberg School of Public HealthBaltimoreMaryland
| |
Collapse
|
12
|
Exome sequencing identifies compound heterozygous KCTD7 mutations in a girl with progressivemyoclonus epilepsy. Clin Chim Acta 2019; 493:87-91. [DOI: 10.1016/j.cca.2019.02.028] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 02/13/2019] [Accepted: 02/27/2019] [Indexed: 12/31/2022]
|
13
|
Zastrow DB, Kohler JN, Bonner D, Reuter CM, Fernandez L, Grove ME, Fisk DG, Yang Y, Eng CM, Ward PA, Bick D, Worthey EA, Fisher PG, Ashley EA, Bernstein JA, Wheeler MT. A toolkit for genetics providers in follow-up of patients with non-diagnostic exome sequencing. J Genet Couns 2019; 28:213-228. [PMID: 30964584 PMCID: PMC7385984 DOI: 10.1002/jgc4.1119] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Revised: 03/01/2019] [Accepted: 03/04/2019] [Indexed: 12/11/2022]
Abstract
There are approximately 7,000 rare diseases affecting 25-30 million Americans, with 80% estimated to have a genetic basis. This presents a challenge for genetics practitioners to determine appropriate testing, make accurate diagnoses, and conduct up-to-date patient management. Exome sequencing (ES) is a comprehensive diagnostic approach, but only 25%-41% of the patients receive a molecular diagnosis. The remaining three-fifths to three-quarters of patients undergoing ES remain undiagnosed. The Stanford Center for Undiagnosed Diseases (CUD), a clinical site of the Undiagnosed Diseases Network, evaluates patients with undiagnosed and rare diseases using a combination of methods including ES. Frequently these patients have non-diagnostic ES results, but strategic follow-up techniques identify diagnoses in a subset. We present techniques used at the CUD that can be adopted by genetics providers in clinical follow-up of cases where ES is non-diagnostic. Solved case examples illustrate different types of non-diagnostic results and the additional techniques that led to a diagnosis. Frequent approaches include segregation analysis, data reanalysis, genome sequencing, additional variant identification, careful phenotype-disease correlation, confirmatory testing, and case matching. We also discuss prioritization of cases for additional analyses.
Collapse
Affiliation(s)
- Diane B Zastrow
- Center for Undiagnosed Diseases, Stanford University, Stanford, California
| | - Jennefer N Kohler
- Center for Undiagnosed Diseases, Stanford University, Stanford, California
| | - Devon Bonner
- Center for Undiagnosed Diseases, Stanford University, Stanford, California
| | - Chloe M Reuter
- Center for Undiagnosed Diseases, Stanford University, Stanford, California
| | - Liliana Fernandez
- Center for Undiagnosed Diseases, Stanford University, Stanford, California
| | - Megan E Grove
- Clinical Genomics Program, Stanford Health Care, Stanford, California
| | - Dianna G Fisk
- Clinical Genomics Program, Stanford Health Care, Stanford, California
| | | | | | | | - David Bick
- HudsonAlpha Institute for Biotechnology, Huntsville, Alabama
| | | | - Paul G Fisher
- Center for Undiagnosed Diseases, Stanford University, Stanford, California
- Department of Neurology, Stanford University School of Medicine, Stanford, California
- Department of Pediatrics, Stanford University School of Medicine, Stanford, California
| | - Euan A Ashley
- Center for Undiagnosed Diseases, Stanford University, Stanford, California
- Clinical Genomics Program, Stanford Health Care, Stanford, California
- Department of Genetics, Stanford University School of Medicine, Stanford, California
- Department of Medicine, Stanford University School of Medicine, Stanford, California
| | - Jonathan A Bernstein
- Center for Undiagnosed Diseases, Stanford University, Stanford, California
- Department of Pediatrics, Stanford University School of Medicine, Stanford, California
| | - Matthew T Wheeler
- Center for Undiagnosed Diseases, Stanford University, Stanford, California
- Department of Medicine, Stanford University School of Medicine, Stanford, California
| |
Collapse
|
14
|
Metz KA, Teng X, Coppens I, Lamb HM, Wagner BE, Rosenfeld JA, Chen X, Zhang Y, Kim HJ, Meadow ME, Wang TS, Haberlandt ED, Anderson GW, Leshinsky-Silver E, Bi W, Markello TC, Pratt M, Makhseed N, Garnica A, Danylchuk NR, Burrow TA, Jayakar P, McKnight D, Agadi S, Gbedawo H, Stanley C, Alber M, Prehl I, Peariso K, Ong MT, Mordekar SR, Parker MJ, Crooks D, Agrawal PB, Berry GT, Loddenkemper T, Yang Y, Maegawa GHB, Aouacheria A, Markle JG, Wohlschlegel JA, Hartman AL, Hardwick JM. KCTD7 deficiency defines a distinct neurodegenerative disorder with a conserved autophagy-lysosome defect. Ann Neurol 2018; 84:766-780. [PMID: 30295347 DOI: 10.1002/ana.25351] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 08/27/2018] [Accepted: 09/23/2018] [Indexed: 12/11/2022]
Abstract
OBJECTIVE Several small case series identified KCTD7 mutations in patients with a rare autosomal recessive disorder designated progressive myoclonic epilepsy (EPM3) and neuronal ceroid lipofuscinosis (CLN14). Despite the name KCTD (potassium channel tetramerization domain), KCTD protein family members lack predicted channel domains. We sought to translate insight gained from yeast studies to uncover disease mechanisms associated with deficiencies in KCTD7 of unknown function. METHODS Novel KCTD7 variants in new and published patients were assessed for disease causality using genetic analyses, cell-based functional assays of patient fibroblasts and knockout yeast, and electron microscopy of patient samples. RESULTS Patients with KCTD7 mutations can exhibit movement disorders or developmental regression before seizure onset, and are distinguished from similar disorders by an earlier age of onset. Although most published KCTD7 patient variants were excluded from a genome sequence database of normal human variations, most newly identified patient variants are present in this database, potentially challenging disease causality. However, genetic analysis and impaired biochemical interactions with cullin 3 support a causal role for patient KCTD7 variants, suggesting deleterious alleles of KCTD7 and other rare disease variants may be underestimated. Both patient-derived fibroblasts and yeast lacking Whi2 with sequence similarity to KCTD7 have impaired autophagy consistent with brain pathology. INTERPRETATION Biallelic KCTD7 mutations define a neurodegenerative disorder with lipofuscin and lipid droplet accumulation but without defining features of neuronal ceroid lipofuscinosis or lysosomal storage disorders. KCTD7 deficiency appears to cause an underlying autophagy-lysosome defect conserved in yeast, thereby assigning a biological role for KCTD7. Ann Neurol 2018;84:774-788.
Collapse
Affiliation(s)
- Kyle A Metz
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD
| | - Xinchen Teng
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD.,Jiangsu Key Laboratory of Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu Province, People's Republic of China
| | - Isabelle Coppens
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD
| | - Heather M Lamb
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD
| | - Bart E Wagner
- Histopathology Department, Royal Hallamshire Hospital, Sheffield, United Kingdom
| | - Jill A Rosenfeld
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Xianghui Chen
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu Province, People's Republic of China
| | - Yu Zhang
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu Province, People's Republic of China
| | - Hee Jong Kim
- Department of Biological Chemistry, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - Michael E Meadow
- Department of Biological Chemistry, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - Tim Sen Wang
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD.,Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Edda D Haberlandt
- Clinical Department of Pediatrics I, Innsbruck Medical University, Innsbruck, Austria.,Department of Child and Youth Health, Hospital of Dornbirn, Dornbirn, Austria
| | - Glenn W Anderson
- Histopathology Department, Great Ormond Street Hospital for Children, London, United Kingdom
| | | | - Weimin Bi
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Thomas C Markello
- NIH Undiagnosed Diseases Program, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD
| | - Marsha Pratt
- Department of Pediatrics, University of Oklahoma College of Medicine, Oklahoma City, OK
| | - Nawal Makhseed
- Department of Pediatrics, Jahra Hospital, Ministry of Health, Al Jahra, Kuwait
| | - Adolfo Garnica
- Department of Pediatrics, University of Arkansas for Medical Sciences and Arkansas Children's Hospital, Little Rock, AR
| | - Noelle R Danylchuk
- Department of Pediatrics, University of Arkansas for Medical Sciences and Arkansas Children's Hospital, Little Rock, AR
| | - Thomas A Burrow
- Department of Pediatrics, University of Arkansas for Medical Sciences and Arkansas Children's Hospital, Little Rock, AR
| | - Parul Jayakar
- Division of Genetics and Metabolism, Nicklaus Children's Hospital, Miami, FL
| | | | - Satish Agadi
- Department of Neurology, Texas Children's Hospital, Houston, TX
| | | | | | - Michael Alber
- Pediatric Neurology and Developmental Medicine, University of Tübingen, Tübingen, Germany
| | | | - Katrina Peariso
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH
| | - Min Tsui Ong
- Department of Paediatric Neurology, Sheffield Children's National Health Service Foundation Trust, Sheffield, United Kingdom
| | - Santosh R Mordekar
- Department of Paediatric Neurology, Sheffield Children's National Health Service Foundation Trust, Sheffield, United Kingdom
| | - Michael J Parker
- Sheffield Clinical Genetics Service, Sheffield Children's National Health Service Foundation Trust, Sheffield, United Kingdom
| | - Daniel Crooks
- Department of Neuropathology, Walton Centre National Health Service Foundation Trust, Liverpool, United Kingdom
| | - Pankaj B Agrawal
- Division of Genetics and Genomics, Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | - Gerard T Berry
- Division of Genetics and Genomics, Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | | | - Yaping Yang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Gustavo H B Maegawa
- Department of Pediatrics/Genetics and Metabolism, University of Florida, Gainesville, FL
| | - Abdel Aouacheria
- Montpellier Institute of Evolution Sciences, University of Montpellier, CNRS, EPHE, IRD, Montpellier, France
| | - Janet G Markle
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD
| | - James A Wohlschlegel
- Department of Biological Chemistry, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - Adam L Hartman
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD
| | - J Marie Hardwick
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD.,Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD.,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD
| |
Collapse
|
15
|
Oyrer J, Maljevic S, Scheffer IE, Berkovic SF, Petrou S, Reid CA. Ion Channels in Genetic Epilepsy: From Genes and Mechanisms to Disease-Targeted Therapies. Pharmacol Rev 2018; 70:142-173. [PMID: 29263209 DOI: 10.1124/pr.117.014456] [Citation(s) in RCA: 163] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 10/02/2017] [Indexed: 12/19/2022] Open
Abstract
Epilepsy is a common and serious neurologic disease with a strong genetic component. Genetic studies have identified an increasing collection of disease-causing genes. The impact of these genetic discoveries is wide reaching-from precise diagnosis and classification of syndromes to the discovery and validation of new drug targets and the development of disease-targeted therapeutic strategies. About 25% of genes identified in epilepsy encode ion channels. Much of our understanding of disease mechanisms comes from work focused on this class of protein. In this study, we review the genetic, molecular, and physiologic evidence supporting the pathogenic role of a number of different voltage- and ligand-activated ion channels in genetic epilepsy. We also review proposed disease mechanisms for each ion channel and highlight targeted therapeutic strategies.
Collapse
Affiliation(s)
- Julia Oyrer
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Snezana Maljevic
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Ingrid E Scheffer
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Samuel F Berkovic
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Steven Petrou
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Christopher A Reid
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| |
Collapse
|
16
|
Chen T, Giri M, Xia Z, Subedi YN, Li Y. Genetic and epigenetic mechanisms of epilepsy: a review. Neuropsychiatr Dis Treat 2017; 13:1841-1859. [PMID: 28761347 PMCID: PMC5516882 DOI: 10.2147/ndt.s142032] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Epilepsy is a common episodic neurological disorder or condition characterized by recurrent epileptic seizures, and genetics seems to play a key role in its etiology. Early linkage studies have localized multiple loci that may harbor susceptibility genes to epilepsy, and mutational analyses have detected a number of mutations involved in both ion channel and nonion channel genes in patients with idiopathic epilepsy. Genome-wide studies of epilepsy have found copy number variants at 2q24.2-q24.3, 7q11.22, 15q11.2-q13.3, and 16p13.11-p13.2, some of which disrupt multiple genes, such as NRXN1, AUTS2, NLGN1, CNTNAP2, GRIN2A, PRRT2, NIPA2, and BMP5, implicated for neurodevelopmental disorders, including intellectual disability and autism. Unfortunately, only a few common genetic variants have been associated with epilepsy. Recent exome-sequencing studies have found some genetic mutations, most of which are located in nonion channel genes such as the LGI1, PRRT2, EFHC1, PRICKLE, RBFOX1, and DEPDC5 and in probands with rare forms of familial epilepsy, and some of these genes are involved with the neurodevelopment. Since epigenetics plays a role in neuronal function from embryogenesis and early brain development to tissue-specific gene expression, epigenetic regulation may contribute to the genetic mechanism of neurodevelopment through which a gene and the environment interacting with each other affect the development of epilepsy. This review focused on the analytic tools used to identify epilepsy and then provided a summary of recent linkage and association findings, indicating the existence of novel genes on several chromosomes for further understanding of the biology of epilepsy.
Collapse
Affiliation(s)
- Tian Chen
- Department of Health Management Center, Chongqing Three Gorges Central Hospital, Chongqing, People's Republic of China
| | - Mohan Giri
- National Center for Rheumatic Diseases, Ratopul, Gaushala, Kathmandu, Nepal
| | - Zhenyi Xia
- Department of Thoracic Surgery, Chongqing Three Gorges Central Hospital, Chongqing, People's Republic of China
| | - Yadu Nanda Subedi
- National Center for Rheumatic Diseases, Ratopul, Gaushala, Kathmandu, Nepal
| | - Yan Li
- Department of Health Management Center, Chongqing Three Gorges Central Hospital, Chongqing, People's Republic of China
| |
Collapse
|
17
|
Badalato L, Farhan SMK, Dilliott AA, Bulman DE, Hegele RA, Goobie SL. KMT2D p.Gln3575His segregating in a family with autosomal dominant choanal atresia strengthens the Kabuki/CHARGE connection. Am J Med Genet A 2016; 173:183-189. [PMID: 27991736 DOI: 10.1002/ajmg.a.38010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 09/21/2016] [Indexed: 11/10/2022]
Abstract
Choanal atresia is rarely reported in Kabuki syndrome, but is a common feature of CHARGE syndrome. Otherwise, the two conditions have a number of overlapping features, and the molecular links between them have recently been elucidated. Here, we report a case of a mother and her two children who presented with congenital choanal atresia. We performed whole exome sequencing on DNA from the mother and her two unaffected parents, and identified a de novo, novel variant in KMT2D. KMT2D p.Gln3575His segregated with disease status in the family, and is associated with a unique and conserved phenotype in the affected family members, with features overlapping with Kabuki and CHARGE syndromes. Our findings further support the potential etiological link between these two classically distinct conditions. © 2016 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Lauren Badalato
- Faculty of Medicine, Department of Genetics, Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Sali M K Farhan
- Department of Biochemistry and Medicine, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Allison A Dilliott
- Department of Biochemistry and Medicine, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | | | - Dennis E Bulman
- Faculty of Medicine, Departments of Pediatrics, Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Robert A Hegele
- Department of Biochemistry and Medicine, Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Sharan L Goobie
- Division of Medical Genetics, Department of Pediatrics, London Health Sciences Centre, Western University, London, Ontario, Canada.,Medical Genetics, Department of Pediatrics, IWK Health Centre, Dalhousie University, Halifax, Nova Scotia, Canada
| |
Collapse
|
18
|
Moen MN, Fjær R, Hamdani EH, Laerdahl JK, Menchini RJ, Vigeland MD, Sheng Y, Undlien DE, Hassel B, Salih MA, El Khashab HY, Selmer KK, Chaudhry FA. Pathogenic variants in KCTD7 perturb neuronal K+ fluxes and glutamine transport. Brain 2016; 139:3109-3120. [PMID: 27742667 DOI: 10.1093/brain/aww244] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 06/11/2016] [Accepted: 08/17/2016] [Indexed: 12/11/2022] Open
Abstract
Progressive myoclonus epilepsy is a heterogeneous group of disorders characterized by myoclonic and tonic-clonic seizures, ataxia and cognitive decline. We here present two affected brothers. At 9 months of age the elder brother developed ataxia and myoclonic jerks. In his second year he lost the ability to walk and talk, and he developed drug-resistant progressive myoclonus epilepsy. The cerebrospinal fluid level of glutamate was decreased while glutamine was increased. His younger brother manifested similar symptoms from 6 months of age. By exome sequencing of the proband we identified a novel homozygous frameshift variant in the potassium channel tetramerization domain 7 (KCTD7) gene (NM_153033.1:c.696delT: p.F232fs), which results in a truncated protein. The identified F232fs variant is inherited in an autosomal recessive manner, and the healthy consanguineous parents carry the variant in a heterozygous state. Bioinformatic analyses and structure modelling showed that KCTD7 is a highly conserved protein, structurally similar to KCTD5 and several voltage-gated potassium channels, and that it may form homo- or heteromultimers. By heterologous expression in Xenopus laevis oocytes, we demonstrate that wild-type KCTD7 hyperpolarizes cells in a K+ dependent manner and regulates activity of the neuronal glutamine transporter SAT2 (Slc38a2), while the F232fs variant impairs K+ fluxes and obliterates SAT2-dependent glutamine transport. Characterization of four additional disease-causing variants (R94W, R184C, N273I, Y276C) bolster these results and reveal the molecular mechanisms involved in the pathophysiology of KCTD7-related progressive myoclonus epilepsy. Thus, our data demonstrate that KCTD7 has an impact on K+ fluxes, neurotransmitter synthesis and neuronal function, and that malfunction of the encoded protein may lead to progressive myoclonus epilepsy.
Collapse
Affiliation(s)
- Marivi Nabong Moen
- 1 The Institute of Basic Medical Sciences, Department of Molecular Medicine, University of Oslo, Oslo, Norway
| | - Roar Fjær
- 2 Department of Medical Genetics, Oslo University Hospital and University of Oslo, Norway
| | - El Hassan Hamdani
- 1 The Institute of Basic Medical Sciences, Department of Molecular Medicine, University of Oslo, Oslo, Norway.,3 Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway
| | - Jon K Laerdahl
- 4 Department of Microbiology, Oslo University Hospital, Oslo, Norway.,5 Bioinformatics Core Facility, Department of Informatics, University of Oslo, Oslo, Norway
| | - Robin Johansen Menchini
- 1 The Institute of Basic Medical Sciences, Department of Molecular Medicine, University of Oslo, Oslo, Norway
| | - Magnus Dehli Vigeland
- 2 Department of Medical Genetics, Oslo University Hospital and University of Oslo, Norway
| | - Ying Sheng
- 2 Department of Medical Genetics, Oslo University Hospital and University of Oslo, Norway
| | - Dag Erik Undlien
- 2 Department of Medical Genetics, Oslo University Hospital and University of Oslo, Norway
| | - Bjørnar Hassel
- 6 Department of Complex Neurology and Neurohabilitation, Oslo University Hospital, Oslo, Norway
| | - Mustafa A Salih
- 7 Division of Paediatric Neurology, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Heba Y El Khashab
- 7 Division of Paediatric Neurology, College of Medicine, King Saud University, Riyadh, Saudi Arabia.,8 Department of Paediatrics, Ain Shams University, Cairo, Egypt
| | - Kaja Kristine Selmer
- 2 Department of Medical Genetics, Oslo University Hospital and University of Oslo, Norway.,9 National Centre for Rare Epilepsy-related Disorders, Oslo University Hospital, Oslo, Norway
| | - Farrukh Abbas Chaudhry
- 1 The Institute of Basic Medical Sciences, Department of Molecular Medicine, University of Oslo, Oslo, Norway .,3 Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway
| |
Collapse
|
19
|
Marcián V, Filip P, Bareš M, Brázdil M. Cerebellar Dysfunction and Ataxia in Patients with Epilepsy: Coincidence, Consequence, or Cause? TREMOR AND OTHER HYPERKINETIC MOVEMENTS (NEW YORK, N.Y.) 2016; 6:376. [PMID: 27375960 PMCID: PMC4925921 DOI: 10.7916/d8kh0nbt] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Accepted: 05/05/2016] [Indexed: 12/15/2022]
Abstract
Basic epilepsy teachings assert that seizures arise from the cerebral cortex, glossing over infratentorial structures such as the cerebellum that are believed to modulate rather than generate seizures. Nonetheless, ataxia and other clinical findings in epileptic patients are slowly but inevitably drawing attention to this neural node. Tracing the evolution of this line of inquiry from the observed coincidence of cerebellar atrophy and cerebellar dysfunction (most apparently manifested as ataxia) in epilepsy to their close association, this review considers converging clinical, physiological, histological, and neuroimaging evidence that support incorporating the cerebellum into epilepsy pathology. We examine reports of still controversial cerebellar epilepsy, studies of cerebellar stimulation alleviating paroxysmal epileptic activity, studies and case reports of cerebellar lesions directly associated with seizures, and conditions in which ataxia is accompanied by epileptic seizures. Finally, the review substantiates the role of this complex brain structure in epilepsy whether by coincidence, as a consequence of deleterious cortical epileptic activity or antiepileptic drugs, or the very cause of the disease.
Collapse
Affiliation(s)
- Václav Marcián
- First Department of Neurology, St. Anne's University Hospital, Brno, Czech Republic; Medical Faculty of Masaryk University, Brno, Czech Republic.,First Department of Neurology, St. Anne's University Hospital, Brno, Czech Republic; Medical Faculty of Masaryk University, Brno, Czech Republic; Behavioral and Social Neuroscience Research Group, CEITEC (Central European Institute of Technology), Masaryk University, Brno, Czech Republic; Department of Neurology, School of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Pavel Filip
- First Department of Neurology, St. Anne's University Hospital, Brno, Czech Republic; Medical Faculty of Masaryk University, Brno, Czech Republic
| | - Martin Bareš
- First Department of Neurology, St. Anne's University Hospital, Brno, Czech Republic; Medical Faculty of Masaryk University, Brno, Czech Republic; Behavioral and Social Neuroscience Research Group, CEITEC (Central European Institute of Technology), Masaryk University, Brno, Czech Republic; Department of Neurology, School of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Milan Brázdil
- First Department of Neurology, St. Anne's University Hospital, Brno, Czech Republic; Medical Faculty of Masaryk University, Brno, Czech Republic; Behavioral and Social Neuroscience Research Group, CEITEC (Central European Institute of Technology), Masaryk University, Brno, Czech Republic
| |
Collapse
|
20
|
Delineation of New Disorders and Phenotypic Expansion of Known Disorders Through Whole Exome Sequencing. CURRENT GENETIC MEDICINE REPORTS 2015. [DOI: 10.1007/s40142-015-0079-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
|
21
|
Abstract
As the genetic etiologies of an expanding number of epilepsy syndromes are revealed, the complexity of the phenotype genotype correlation increases. As our review will show, multiple gene mutations cause different epilepsy syndromes, making identification of the specific mutation increasingly more important for prognostication and often more directed treatment. Examples of that include the need to avoid specific drugs in Dravet syndrome and the ongoing investigations of the potential use of new directed therapies such as retigabine in KCNQ2-related epilepsies, quinidine in KCNT1-related epilepsies, and memantine in GRIN2A-related epilepsies.
Collapse
Affiliation(s)
- Abeer J Hani
- Division of Pediatric Neurology, Department of Pediatrics, Duke Children's Hospital and Health Center, Suite T0913J, 2301 Erwin Road, Durham, NC 27710, USA
| | - Husam M Mikati
- Center of Human Genome Variation, LSRC, Duke University School of Medicine, 201 Trent Drive, Durham, NC 27710, USA
| | - Mohamad A Mikati
- Division of Pediatric Neurology, Department of Pediatrics, Duke Children's Hospital and Health Center, Suite T0913J, 2301 Erwin Road, Durham, NC 27710, USA.
| |
Collapse
|
22
|
Cell biology of the NCL proteins: What they do and don't do. Biochim Biophys Acta Mol Basis Dis 2015; 1852:2242-55. [PMID: 25962910 DOI: 10.1016/j.bbadis.2015.04.027] [Citation(s) in RCA: 128] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 04/23/2015] [Accepted: 04/24/2015] [Indexed: 02/06/2023]
Abstract
The fatal, primarily childhood neurodegenerative disorders, neuronal ceroid lipofuscinoses (NCLs), are currently associated with mutations in 13 genes. The protein products of these genes (CLN1 to CLN14) differ in their function and their intracellular localization. NCL-associated proteins have been localized mostly in lysosomes (CLN1, CLN2, CLN3, CLN5, CLN7, CLN10, CLN12 and CLN13) but also in the Endoplasmic Reticulum (CLN6 and CLN8), or in the cytosol associated to vesicular membranes (CLN4 and CLN14). Some of them such as CLN1 (palmitoyl protein thioesterase 1), CLN2 (tripeptidyl-peptidase 1), CLN5, CLN10 (cathepsin D), and CLN13 (cathepsin F), are lysosomal soluble proteins; others like CLN3, CLN7, and CLN12, have been proposed to be lysosomal transmembrane proteins. In this review, we give our views and attempt to summarize the proposed and confirmed functions of each NCL protein and describe and discuss research results published since the last review on NCL proteins. This article is part of a Special Issue entitled: "Current Research on the Neuronal Ceroid Lipofuscinoses (Batten Disease)".
Collapse
|