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Couto B, Galosi S, Steel D, Kurian MA, Friedman J, Gorodetsky C, Lang AE. Severe Acute Motor Exacerbations (SAME) across Metabolic, Developmental and Genetic Disorders. Mov Disord 2024. [PMID: 39119747 DOI: 10.1002/mds.29905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 06/08/2024] [Accepted: 06/13/2024] [Indexed: 08/10/2024] Open
Abstract
Acute presentation of severe motor disorders is a diagnostic and management challenge. We define severe acute motor exacerbations (SAME) as acute/subacute motor symptoms that persist for hours-to-days with a severity that compromise vital signs (temperature, breath, and heart rate) and bulbar function (swallowing/dysphagia). Phenomenology includes dystonia, choreoathetosis, combined movement disorders, weakness, and hemiplegic attacks. SAME can develop in diverse diseases and can be preceded by triggers or catabolic states. Recent descriptions of SAME in complex neurodevelopmental and epileptic encephalopathies have broadened appreciation of this presentation beyond inborn errors of metabolism. A high degree of clinical suspicion is required to identify appropriately targeted investigations and management. We conducted a comprehensive literature analysis of etiologies. Reported triggers are described and classified as per pathophysiological mechanism. A video of six cases displaying multiple SAME with diverse outcomes is provided. We identified 50 different conditions that manifest SAME, some associated with developmental regression. Etiologies include disorders of metabolism: energy substrate, amino acids, complex molecules, vitamins/cofactors, minerals, and neurotransmitters/synaptic vesicle cycling. Non-metabolic neurodegenerative and genetic disorders that present with movement disorders and epilepsy can additionally manifest SAME. A limited number of triggers are grouped here, together with an approach to investigations and general management strategies. Several neurogenetic and neurometabolic disorders manifest SAME. Identifying triggers can help in certain cases narrow the differential diagnosis and guide the expeditious application of targeted therapies to minimize adverse developmental and neurological consequences. This process may inform pathogenesis and eventually improve our understanding of the mechanisms that lead to the development of SAME. © 2024 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Blas Couto
- Edmond J. Safra Program in Parkinson's Disease, Rossy PSP Centre and the Morton and Gloria Shulman Movement Disorders Clinic, Toronto Western Hospital, Toronto, Ontario, Canada
- Instituto de Neurociencia Cognitiva y Traslacional, INECO-Favaloro-CONICET, Buenos Aires, Argentina
| | - Serena Galosi
- Department of Human Neuroscience, Sapienza University, Rome, Italy
| | - Dora Steel
- Molecular Neurosciences, Developmental Neurosciences, Zayed Centre for Research into Rare Disease in Children, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
- Department of Neurology, Great Ormond Street Hospital, London, United Kingdom
| | - Manju A Kurian
- Molecular Neurosciences, Developmental Neurosciences, Zayed Centre for Research into Rare Disease in Children, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
- Department of Neurology, Great Ormond Street Hospital, London, United Kingdom
| | - Jennifer Friedman
- Departments of Neurosciences and Pediatrics, University of California San Diego, San Diego, California, USA
- Division of Neurology, Rady Children's Hospital; Rady Children's Institute for Genomic Medicine, San Diego, California, USA
| | - Carolina Gorodetsky
- Division of Neurology, Pediatric Deep Brain Stimulation Program, Movement Disorder and Neuromodulation Program at the Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Anthony E Lang
- Edmond J. Safra Program in Parkinson's Disease, Rossy PSP Centre and the Morton and Gloria Shulman Movement Disorders Clinic, Toronto Western Hospital, Toronto, Ontario, Canada
- Tanz Centre for Research in Neurodegenerative Disease, University of Toronto, Toronto, Ontario, Canada
- Department of Medicine, Division of Neurology, University Health Network and the University of Toronto, Toronto, Ontario, Canada
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Kubota K, Adachi M, Fujii H, Saitsu H, Ohnishi H. Spontaneous Remission of Epileptic Seizures Following Norovirus Infection in a Patient With DNM1 Encephalopathy. Cureus 2024; 16:e60748. [PMID: 38903324 PMCID: PMC11188033 DOI: 10.7759/cureus.60748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/20/2024] [Indexed: 06/22/2024] Open
Abstract
Epileptic seizures can be worsened by infections; however, they sometimes disappear or decrease after an acute viral infection, although this is rare. We report the spontaneous remission of epileptic seizures following norovirus-induced viral gastroenteritis in a boy with DNM1 encephalopathy. He had clonic seizures daily from the age of two months and developed epileptic spasms at 14 months of age; he was admitted to the hospital at this time. A physical examination revealed hypotonia, strabismus, tongue protrusion with drooping, and widely spaced teeth. Although brain magnetic resonance imaging was unremarkable, electroencephalography revealed frequent occipital spikes. Three days after admission, the patient developed frequent diarrhea without a fever. A rapid immunochromatographic test of norovirus in a stool sample was positive. Immediately after the appearance of diarrhea, the epileptic seizures disappeared. Currently, at the age of five years, the patient has a profound psychomotor developmental delay; he has no verbal expression and is unable to walk. He has experienced involuntary movements of the myoclonus since 10 months of age. Whole-exome sequencing of the patient's DNA revealed the presence of a heterozygous de novo variant of DNM1: c.709C>T (p.Arg237Trp). Although the findings from our patient suggest that underlying neural network abnormalities were ameliorated by immunological mechanisms as a result of the viral infection, further research is needed to clarify the mechanisms behind this spontaneous remission of seizures.
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Affiliation(s)
- Kazuo Kubota
- Department of Pediatrics, Graduate School of Medicine, Gifu University, Gifu, JPN
| | - Miho Adachi
- Department of Pediatrics, Graduate School of Medicine, Gifu University, Gifu, JPN
| | - Hidehiko Fujii
- Department of Pediatrics, Ogaki Municipal Hospital, Ogaki, JPN
| | - Hirotomo Saitsu
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, JPN
| | - Hidenori Ohnishi
- Department of Pediatrics, Graduate School of Medicine, Gifu University, Gifu, JPN
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Matsubara K, Kuki I, Ishioka R, Yamada N, Fukuoka M, Inoue T, Nukui M, Okamoto N, Mizuguchi T, Matsumoto N, Okazaki S. Abnormal axonal development and severe epileptic phenotype in Dynamin-1 (DNM1) encephalopathy. Epileptic Disord 2024; 26:139-143. [PMID: 38009673 DOI: 10.1002/epd2.20181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 11/09/2023] [Accepted: 11/18/2023] [Indexed: 11/29/2023]
Abstract
Dynamin-1 (DNM1) is involved in synaptic vesicle recycling, and DNM1 mutations can lead to developmental and epileptic encephalopathy. The neuroimaging of DNM1 encephalopathy has not been reported in detail. We describe a severe phenotype of DNM1 encephalopathy showing characteristic neuroradiological features. In addition, we reviewed previously reported cases who have DNM1 pathogenic variants with white matter abnormalities. Our case presented drug-resistant seizures from 1 month of age and epileptic spasms at 2 years of age. Brain MRI showed no progression of myelination, progression of diffuse cerebral atrophy, and a thin corpus callosum. Proton magnetic resonance spectroscopy showed a decreased N-acetylaspartate peak and diffusion tensor imaging presented with less pyramidal decussation. Whole-exome sequencing revealed a recurrent de novo heterozygous variant of DNM1. So far, more than 50 cases of DNM1 encephalopathy have been reported. Among these patients, delayed myelination occurred in two cases of GTPase-domain DNM1 encephalopathy and in six cases of middle-domain DNM1 encephalopathy. The neuroimaging findings in this case suggest inadequate axonal development. DNM1 is involved in the release of synaptic vesicles with the inhibitory transmitter GABA, suggesting that GABAergic neuron dysfunction is the mechanism of refractory epilepsy in DNM1 encephalopathy. GABA-mediated signaling mechanisms play important roles in axonal development and GABAergic neuron dysfunction may be cause of white matter abnormalities in DNM1 encephalopathy.
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Affiliation(s)
- Kohei Matsubara
- Division of Pediatric Neurology, Osaka City General Hospital, Osaka, Japan
| | - Ichiro Kuki
- Division of Pediatric Neurology, Osaka City General Hospital, Osaka, Japan
| | - Risako Ishioka
- Division of Pediatric Neurology, Osaka City General Hospital, Osaka, Japan
| | - Naoki Yamada
- Division of Pediatric Neurology, Osaka City General Hospital, Osaka, Japan
| | - Masataka Fukuoka
- Division of Pediatric Neurology, Osaka City General Hospital, Osaka, Japan
| | - Takeshi Inoue
- Division of Pediatric Neurology, Osaka City General Hospital, Osaka, Japan
| | - Megumi Nukui
- Division of Pediatric Neurology, Osaka City General Hospital, Osaka, Japan
| | - Nobuhiko Okamoto
- Division of Medical Genetics, Osaka Women's and Children's Hospital, Osaka, Japan
| | - Takeshi Mizuguchi
- Division of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Naomichi Matsumoto
- Division of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Shin Okazaki
- Division of Pediatric Neurology, Osaka City General Hospital, Osaka, Japan
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Banerjee R, Mukherjee A, Adhikary A, Sharma S, Hussain MS, Ali ME, Nagotu S. Insights into the role of the conserved GTPase domain residues T62 and S277 in yeast Dnm1. Int J Biol Macromol 2023; 253:127381. [PMID: 37838106 DOI: 10.1016/j.ijbiomac.2023.127381] [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: 06/08/2023] [Revised: 09/10/2023] [Accepted: 10/09/2023] [Indexed: 10/16/2023]
Abstract
Mitochondrial division is a highly regulated process. The master regulator of this process is the multi-domain, conserved protein called Dnm1 in yeast. In this study, we systematically analyzed two residues, T62 and S277, reported to be putatively phosphorylated in the GTPase domain of the protein. These residues lie in the G2 and G5 motifs of the GTPase domain. Both residues are important for the function of the protein, as evident from in vivo and in vitro analysis of the non-phosphorylatable and phosphomimetic variants. Dnm1T62A/D and Dnm1S277A/D showed differences with respect to the protein localization and puncta dynamics in vivo, albeit both were non-functional as assessed by mitochondrial morphology and GTPase activity. Overall, the secondary structure of the protein variants was unaltered, but local conformational changes were observed. Interestingly, both Dnm1T62A/D and Dnm1S277A/D exhibited dominant-negative behavior when expressed in cells containing endogenous Dnm1. To our knowledge, we report for the first time a single residue (S277) change that does not alter the localization of Dnm1 but makes it non-functional in a dominant-negative manner. Intriguingly, the two residues analyzed in this study are present in the same domain but exhibit variable effects when mutated to alanine or aspartic acid.
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Affiliation(s)
- Riddhi Banerjee
- Organelle Biology and Cellular Ageing Lab, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Agradeep Mukherjee
- Organelle Biology and Cellular Ageing Lab, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Ankita Adhikary
- Organelle Biology and Cellular Ageing Lab, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Shikha Sharma
- Institute of Nano Science and Technology, Knowledge City, Sector-81, Mohali, Punjab 140306, India
| | - Md Saddam Hussain
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Md Ehesan Ali
- Institute of Nano Science and Technology, Knowledge City, Sector-81, Mohali, Punjab 140306, India
| | - Shirisha Nagotu
- Organelle Biology and Cellular Ageing Lab, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India.
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5
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Afsar T, Huang X, Shah AA, Abbas S, Bano S, Mahmood A, Hu J, Razak S, Umair M. Truncated DNM1 variant underlines developmental delay and epileptic encephalopathy. Front Pediatr 2023; 11:1266376. [PMID: 37900685 PMCID: PMC10601988 DOI: 10.3389/fped.2023.1266376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 09/06/2023] [Indexed: 10/31/2023] Open
Abstract
Background Developmental and epileptic encephalopathies (DEEs) signify a group of heterogeneous neurodevelopmental disorder associated with early-onset seizures accompanied by developmental delay, hypotonia, mild to severe intellectual disability, and developmental regression. Variants in the DNM1 gene have been associated with autosomal dominant DEE type 31A and autosomal recessive DEE type 31B. Methods In the current study, a consanguineous Pakistani family consisting of a proband (IV-2) was clinically evaluated and genetically analyzed manifesting in severe neurodevelopmental phenotypes. WES followed by Sanger sequencing was performed to identify the disease-causing variant. Furthermore, 3D protein modeling and dynamic simulation of wild-type and mutant proteins along with reverse transcriptase (RT)-based mRNA expression were checked using standard methods. Results Data analysis of WES revealed a novel homozygous non-sense variant (c.1402G>T; p. Glu468*) in exon 11 of the DNM1 gene that was predicted as pathogenic class I. Variants in the DNM1 gene have been associated with DEE types 31A and B. Different bioinformatics prediction tools and American College of Medical Genetics guidelines were used to verify the identified variant. Sanger sequencing was used to validate the disease-causing variant. Our approach validated the pathogenesis of the variant as a cause of heterogeneous neurodevelopmental disorders. In addition, 3D protein modeling showed that the mutant protein would lose most of the amino acids and might not perform the proper function if the surveillance non-sense-mediated decay mechanism was skipped. Molecular dynamics analysis showed varied trajectories of wild-type and mutant DNM1 proteins in terms of root mean square deviation, root mean square fluctuation and radius of gyration. Similarly, RT-qPCR revealed a substantial reduction of the DNM1 gene in the index patient. Conclusion Our finding further confirms the association of homozygous, loss-of-function variants in DNM1 associated with DEE type 31B. The study expands the genotypic and phenotypic spectrum of pathogenic DNM1 variants related to DNM1-associated pathogenesis.
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Affiliation(s)
- Tayyaba Afsar
- Department of Community Health Sciences, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia
- King Salman Center for Disability Research, Riyadh, Saudi Arabia
| | - Xiaoyun Huang
- Department of Neurology, SSL Central Hospital of Dongguan City, Affiliated Dongguan Shilong People’s Hospital of Southern Medical University, Dongguan, China
| | - Abid Ali Shah
- Center for Medical Genetics and Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, China
| | - Safdar Abbas
- Department of Biological Sciences, Dartmouth College, Hanover, NH, United States
| | - Shazia Bano
- Department of Optometry and Vision Sciences, University of Lahore, Lahore, Pakistan
| | - Arif Mahmood
- Department of Neurology, SSL Central Hospital of Dongguan City, Affiliated Dongguan Shilong People’s Hospital of Southern Medical University, Dongguan, China
| | - Junjian Hu
- Department of Central Laboratory, SSL Central Hospital of Dongguan City, Affiliated Dongguan Shilong People’s Hospital of Southern Medical University, Dongguan, China
| | - Suhail Razak
- Department of Community Health Sciences, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia
- King Salman Center for Disability Research, Riyadh, Saudi Arabia
| | - Muhammad Umair
- King Salman Center for Disability Research, Riyadh, Saudi Arabia
- Medical Genomics Research Department, King Abdullah International Medical Research Center (KAIMRC), King Saud Bin Abdulaziz University for Health Sciences, Ministry of National Guard Health Affairs (MNGH), Riyadh, Saudi Arabia
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Abdi M, Aliyev E, Trost B, Kohailan M, Aamer W, Syed N, Shaath R, Gandhi GD, Engchuan W, Howe J, Thiruvahindrapuram B, Geng M, Whitney J, Syed A, Lakshmi J, Hussein S, Albashir N, Hussein A, Poggiolini I, Elhag SF, Palaniswamy S, Kambouris M, de Fatima Janjua M, Tahir MOE, Nazeer A, Shahwar D, Azeem MW, Mokrab Y, Aati NA, Akil A, Scherer SW, Kamal M, Fakhro KA. Genomic architecture of autism spectrum disorder in Qatar: The BARAKA-Qatar Study. Genome Med 2023; 15:81. [PMID: 37805537 PMCID: PMC10560429 DOI: 10.1186/s13073-023-01228-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 09/04/2023] [Indexed: 10/09/2023] Open
Abstract
BACKGROUND Autism spectrum disorder (ASD) is a neurodevelopmental condition characterized by impaired social and communication skills, restricted interests, and repetitive behaviors. The prevalence of ASD among children in Qatar was recently estimated to be 1.1%, though the genetic architecture underlying ASD both in Qatar and the greater Middle East has been largely unexplored. Here, we describe the first genomic data release from the BARAKA-Qatar Study-a nationwide program building a broadly consented biorepository of individuals with ASD and their families available for sample and data sharing and multi-omics research. METHODS In this first release, we present a comprehensive analysis of whole-genome sequencing (WGS) data of the first 100 families (372 individuals), investigating the genetic architecture, including single-nucleotide variants (SNVs), copy number variants (CNVs), tandem repeat expansions (TREs), as well as mitochondrial DNA variants (mtDNA) segregating with ASD in local families. RESULTS Overall, we identify potentially pathogenic variants in known genes or regions in 27 out of 100 families (27%), of which 11 variants (40.7%) were classified as pathogenic or likely-pathogenic based on American College of Medical Genetics (ACMG) guidelines. Dominant variants, including de novo and inherited, contributed to 15 (55.6%) of these families, consisting of SNVs/indels (66.7%), CNVs (13.3%), TREs (13.3%), and mtDNA variants (6.7%). Moreover, homozygous variants were found in 7 families (25.9%), with a sixfold increase in homozygous burden in consanguineous versus non-consanguineous families (13.6% and 1.8%, respectively). Furthermore, 28 novel ASD candidate genes were identified in 20 families, 23 of which had recurrent hits in MSSNG and SSC cohorts. CONCLUSIONS This study illustrates the value of ASD studies in under-represented populations and the importance of WGS as a comprehensive tool for establishing a molecular diagnosis for families with ASD. Moreover, it uncovers a significant role for recessive variation in ASD architecture in consanguineous settings and provides a unique resource of Middle Eastern genomes for future research to the global ASD community.
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Affiliation(s)
- Mona Abdi
- College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
- Department of Genetics, Sidra Medicine, Doha, Qatar
| | - Elbay Aliyev
- Department of Genetics, Sidra Medicine, Doha, Qatar
| | - Brett Trost
- The Centre for Applied Genomics, The Hospital for Sick Children, Toronto, ON, Canada
- Genetics and Genome Biology Program, The Hospital for Sick Children, Toronto, ON, Canada
| | | | - Waleed Aamer
- Department of Genetics, Sidra Medicine, Doha, Qatar
| | - Najeeb Syed
- Genomics Data Science Core, Sidra Medicine, Doha, Qatar
| | - Rulan Shaath
- Department of Genetics, Sidra Medicine, Doha, Qatar
| | | | - Worrawat Engchuan
- The Centre for Applied Genomics, The Hospital for Sick Children, Toronto, ON, Canada
- Genetics and Genome Biology Program, The Hospital for Sick Children, Toronto, ON, Canada
| | - Jennifer Howe
- The Centre for Applied Genomics, The Hospital for Sick Children, Toronto, ON, Canada
- Genetics and Genome Biology Program, The Hospital for Sick Children, Toronto, ON, Canada
| | - Bhooma Thiruvahindrapuram
- The Centre for Applied Genomics, The Hospital for Sick Children, Toronto, ON, Canada
- Genetics and Genome Biology Program, The Hospital for Sick Children, Toronto, ON, Canada
| | - Melissa Geng
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Joe Whitney
- The Centre for Applied Genomics, The Hospital for Sick Children, Toronto, ON, Canada
- Genetics and Genome Biology Program, The Hospital for Sick Children, Toronto, ON, Canada
| | - Amira Syed
- Department of Genetics, Sidra Medicine, Doha, Qatar
| | | | - Sura Hussein
- Department of Genetics, Sidra Medicine, Doha, Qatar
| | | | - Amal Hussein
- Department of Genetics, Sidra Medicine, Doha, Qatar
| | | | - Saba F Elhag
- Department of Genetics, Sidra Medicine, Doha, Qatar
- Hamad Medical Corporation, Doha, Qatar
| | | | - Marios Kambouris
- Pathology and Laboratory Medicine Department, Genetics Division, Sidra Medicine, Doha, Qatar
| | | | | | - Ahsan Nazeer
- Department of Psychiatry, Sidra Medicine, Doha, Qatar
- Weill Cornell Medicine, Doha, Qatar
| | - Durre Shahwar
- Department of Psychiatry, Sidra Medicine, Doha, Qatar
- Weill Cornell Medicine, Doha, Qatar
| | - Muhammad Waqar Azeem
- Department of Psychiatry, Sidra Medicine, Doha, Qatar
- Weill Cornell Medicine, Doha, Qatar
| | - Younes Mokrab
- Department of Genetics, Sidra Medicine, Doha, Qatar
- Department of Genetic Medicine, Weill Cornell Medicine, Doha, Qatar
- Qatar University, Doha, Qatar
| | | | - Ammira Akil
- Department of Genetics, Sidra Medicine, Doha, Qatar
| | - Stephen W Scherer
- The Centre for Applied Genomics, The Hospital for Sick Children, Toronto, ON, Canada
- Genetics and Genome Biology Program, The Hospital for Sick Children, Toronto, ON, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
- McLaughlin Centre, University of Toronto, Toronto, ON, Canada
| | - Madeeha Kamal
- Department of Pediatrics, Sidra Medicine, Doha, Qatar
| | - Khalid A Fakhro
- College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar.
- Department of Genetics, Sidra Medicine, Doha, Qatar.
- Department of Genetic Medicine, Weill Cornell Medicine, Doha, Qatar.
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Harms FL, Weiss D, Lisfeld J, Alawi M, Kutsche K. A deep intronic variant in DNM1 in a patient with developmental and epileptic encephalopathy creates a splice acceptor site and affects only transcript variants including exon 10a. Neurogenetics 2023; 24:171-180. [PMID: 37039969 DOI: 10.1007/s10048-023-00716-w] [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: 01/30/2023] [Accepted: 03/28/2023] [Indexed: 04/12/2023]
Abstract
DNM1 developmental and epileptic encephalopathy (DEE) is characterized by severe to profound intellectual disability, hypotonia, movement disorder, and refractory epilepsy, typically presenting with infantile spasms. Most of the affected individuals had de novo missense variants in DNM1. DNM1 undergoes alternative splicing that results in expression of six different transcript variants. One alternatively spliced region affects the tandemly arranged exons 10a and 10b, producing isoforms DNM1A and DNM1B, respectively. Pathogenic variants in the DNM1 coding region affect all transcript variants. Recently, a de novo DNM1 NM_001288739.1:c.1197-8G > A variant located in intron 9 has been reported in several unrelated individuals with DEE that causes in-frame insertion of two amino acids and leads to disease through a dominant-negative mechanism. We report on a patient with DEE and a de novo DNM1 variant NM_001288739.2:c.1197-46C > G in intron 9, upstream of exon 10a. By RT-PCR and Sanger sequencing using fibroblast-derived cDNA of the patient, we identified aberrantly spliced DNM1 mRNAs with exon 9 spliced to the last 45 nucleotides of intron 9 followed by exon 10a (NM_001288739.2:r.1196_1197ins[1197-1_1197-45]). The encoded DNM1A mutant is predicted to contain 15 novel amino acids between Ile398 and Arg399 [NP_001275668.1:p.(Ile398_Arg399ins15)] and likely functions in a dominant-negative manner, similar to other DNM1 mutants. Our data confirm the importance of the DNM1 isoform A for normal human brain function that is underscored by previously reported predominant expression of DMN1A transcripts in pediatric brain, functional differences of the mouse Dnm1a and Dnm1b isoforms, and the Dnm1 fitful mouse, an epilepsy mouse model.
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Affiliation(s)
- Frederike L Harms
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany
| | - Deike Weiss
- Department of Pediatrics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Jasmin Lisfeld
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany
| | - Malik Alawi
- Bioinformatics Core, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Kerstin Kutsche
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany.
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AlTassan R, AlQudairy H, Alromayan R, Alfalah A, AlHarbi OA, González-Álvarez AC, Arold ST, Kaya N. Clinical, Radiological, and Genetic Characterization of a Patient with a Novel Homoallelic Loss-of-Function Variant in DNM1. Genes (Basel) 2022; 13:genes13122252. [PMID: 36553519 PMCID: PMC9777962 DOI: 10.3390/genes13122252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 11/23/2022] [Accepted: 11/24/2022] [Indexed: 12/02/2022] Open
Abstract
Heterozygous pathogenic variants in DNM1 are linked to an autosomal dominant form of epileptic encephalopathy. Recently, homozygous loss-of-function variants in DNM1 were reported to cause an autosomal recessive form of developmental and epileptic encephalopathy in unrelated patients. Here, we investigated a singleton from a first-degree cousin marriage who presented with facial dysmorphism, global developmental delay, seizure disorder, and nystagmus. To identify the involvement of any likely genetic cause, diagnostic clinical exome sequencing was performed. Comprehensive filtering revealed a single plausible candidate variant in DNM1. Sanger sequencing of the trio, the patient, and her parents, confirmed the full segregation of the variant. The variant is a deletion leading to a premature stop codon and is predicted to cause a protein truncation. Structural modeling implicated a complete loss of function of the Dynamin 1 (DNM1). Such mutation is predicted to impair the nucleotide binding, dimer formation, and GTPase activity of DNM1. Our study expands the phenotypic spectrum of pathogenic homozygous loss-of-function variants in DNM1.
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Affiliation(s)
- Ruqaiah AlTassan
- Department of Medical Genomics, Centre for Genomic Medicine, MBC: 75, P.O. Box 3354, King Faisal Specialist Hospital, and Research Centre, Riyadh 11211, Saudi Arabia
- College of Medicine, P.O. Box 50927, AlFaisal University, Riyadh 11533, Saudi Arabia
| | - Hanan AlQudairy
- Translational Genomic Department, Centre for Genomic Medicine, MBC: 03, P.O. Box 3354, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia
| | - Rakan Alromayan
- Translational Genomic Department, Centre for Genomic Medicine, MBC: 03, P.O. Box 3354, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia
- College of Medicine, King Saud University, Riyadh 11451, Saudi Arabia
| | - Abdullah Alfalah
- Department of Medical Genomics, Centre for Genomic Medicine, MBC: 75, P.O. Box 3354, King Faisal Specialist Hospital, and Research Centre, Riyadh 11211, Saudi Arabia
| | - Omar A. AlHarbi
- Department of Radiology, MBC: 28, P.O. Box 3354, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia
| | - Ana C. González-Álvarez
- Bioengineering Program, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Stefan T. Arold
- Bioengineering Program, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
- Computational Biology Research Center, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
- Centre de Biologie Structurale (CBS), INSERM, CNRS, Université de Montpellier, F-34090 Montpellier, France
| | - Namik Kaya
- Translational Genomic Department, Centre for Genomic Medicine, MBC: 03, P.O. Box 3354, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia
- Correspondence: ; Tel.: +966-112162919 (ext. 39612)
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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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Spoto G, Valentini G, Saia MC, Butera A, Amore G, Salpietro V, Nicotera AG, Di Rosa G. Synaptopathies in Developmental and Epileptic Encephalopathies: A Focus on Pre-synaptic Dysfunction. Front Neurol 2022; 13:826211. [PMID: 35350397 PMCID: PMC8957959 DOI: 10.3389/fneur.2022.826211] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 01/24/2022] [Indexed: 12/25/2022] Open
Abstract
The proper connection between the pre- and post-synaptic nervous cells depends on any element constituting the synapse: the pre- and post-synaptic membranes, the synaptic cleft, and the surrounding glial cells and extracellular matrix. An alteration of the mechanisms regulating the physiological synergy among these synaptic components is defined as “synaptopathy.” Mutations in the genes encoding for proteins involved in neuronal transmission are associated with several neuropsychiatric disorders, but only some of them are associated with Developmental and Epileptic Encephalopathies (DEEs). These conditions include a heterogeneous group of epilepsy syndromes associated with cognitive disturbances/intellectual disability, autistic features, and movement disorders. This review aims to elucidate the pathogenesis of these conditions, focusing on mechanisms affecting the neuronal pre-synaptic terminal and its role in the onset of DEEs, including potential therapeutic approaches.
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Affiliation(s)
- Giulia Spoto
- Unit of Child Neurology and Psychiatry, Department of Human Pathology of the Adult and Developmental Age “Gaetano Barresi”, University of Messina, Messina, Italy
| | - Giulia Valentini
- Unit of Child Neurology and Psychiatry, Department of Human Pathology of the Adult and Developmental Age “Gaetano Barresi”, University of Messina, Messina, Italy
| | - Maria Concetta Saia
- Unit of Child Neurology and Psychiatry, Department of Human Pathology of the Adult and Developmental Age “Gaetano Barresi”, University of Messina, Messina, Italy
| | - Ambra Butera
- Unit of Child Neurology and Psychiatry, Department of Human Pathology of the Adult and Developmental Age “Gaetano Barresi”, University of Messina, Messina, Italy
| | - Greta Amore
- Unit of Child Neurology and Psychiatry, Department of Human Pathology of the Adult and Developmental Age “Gaetano Barresi”, University of Messina, Messina, Italy
| | - Vincenzo Salpietro
- Department of Neuromuscular Disorders, Institute of Neurology, University College London, London, United Kingdom
- Pediatric Neurology and Muscular Diseases Unit, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Giannina Gaslini, Genoa, Italy
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy
- *Correspondence: Vincenzo Salpietro
| | - Antonio Gennaro Nicotera
- Unit of Child Neurology and Psychiatry, Department of Human Pathology of the Adult and Developmental Age “Gaetano Barresi”, University of Messina, Messina, Italy
| | - Gabriella Di Rosa
- Unit of Child Neurology and Psychiatry, Department of Human Pathology of the Adult and Developmental Age “Gaetano Barresi”, University of Messina, Messina, Italy
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11
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Generation of an induced pluripotent stem cell line (FDCHI007-A) derived from a patient with Developmental and epileptic encephalopathy Type 31 carrying heterozygous c.545 C>A mutation in DNM1 gene. Stem Cell Res 2022; 60:102709. [DOI: 10.1016/j.scr.2022.102709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Revised: 01/23/2022] [Accepted: 02/10/2022] [Indexed: 11/21/2022] Open
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12
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Yigit G, Sheffer R, Daana M, Li Y, Kaygusuz E, Mor-Shakad H, Altmüller J, Nürnberg P, Douiev L, Kaulfuss S, Burfeind P, Wollnik B, Brockmann K. Loss-of-function variants in DNM1 cause a specific form of developmental and epileptic encephalopathy only in biallelic state. J Med Genet 2021; 59:549-553. [PMID: 34172529 PMCID: PMC9132866 DOI: 10.1136/jmedgenet-2021-107769] [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] [Received: 02/17/2021] [Accepted: 05/08/2021] [Indexed: 11/23/2022]
Abstract
Background Developmental and epileptic encephalopathies (DEEs) represent a group of severe neurological disorders characterised by an onset of refractory seizures during infancy or early childhood accompanied by psychomotor developmental delay or regression. DEEs are genetically heterogeneous with, to date, more than 80 different genetic subtypes including DEE31 caused by heterozygous missense variants in DNM1. Methods We performed a detailed clinical characterisation of two unrelated patients with DEE and used whole-exome sequencing to identify causative variants in these individuals. The identified variants were tested for cosegregation in the respective families. Results We excluded pathogenic variants in known, DEE-associated genes. We identified homozygous nonsense variants, c.97C>T; p.(Gln33*) in family 1 and c.850C>T; p.(Gln284*) in family 2, in the DNM1 gene, indicating that biallelic, loss-of-function pathogenic variants in DNM1 cause DEE. Conclusion Our finding that homozygous, loss-of-function variants in DNM1 cause DEE expands the spectrum of pathogenic variants in DNM1. All parents who were heterozygous carriers of the identified loss-of-function variants were healthy and did not show any clinical symptoms, indicating that the type of mutation in DNM1 determines the pattern of inheritance.
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Affiliation(s)
- Gökhan Yigit
- Institute of Human Genetics, University Medical Center Göttingen, Gottingen, Germany
| | - Ruth Sheffer
- Department of Human Genetics, Hadassah University Hospital, Jerusalem, Israel
| | - Muhannad Daana
- Child Development Institute, Clalit Health Services, Tel Aviv, Israel
| | - Yun Li
- Institute of Human Genetics, University Medical Center Göttingen, Gottingen, Germany
| | - Emrah Kaygusuz
- Institute of Human Genetics, University Medical Center Göttingen, Gottingen, Germany.,Molecular Biology and Genetics, Bilecik Şeyh Edebali University, Bilecik, Turkey
| | - Hagar Mor-Shakad
- Department of Human Genetics, Hadassah University Hospital, Jerusalem, Israel
| | - Janine Altmüller
- Cologne Center for Genomics (CCG), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Peter Nürnberg
- Cologne Center for Genomics (CCG), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Liza Douiev
- Department of Human Genetics, Hadassah University Hospital, Jerusalem, Israel
| | - Silke Kaulfuss
- Institute of Human Genetics, University Medical Center Göttingen, Gottingen, Germany
| | - Peter Burfeind
- Institute of Human Genetics, University Medical Center Göttingen, Gottingen, Germany
| | - Bernd Wollnik
- Institute of Human Genetics, University Medical Center Göttingen, Gottingen, Germany .,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Gottingen, Gottingen, Germany
| | - Knut Brockmann
- Interdisciplinary Pediatric Center for Children with Developmental Disabilities and Severe Chronic Disorders, University Medical Center Göttingen, Gottingen, Germany
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Banerjee R, Kumar A, Satpati P, Nagotu S. Mimicking human Drp1 disease-causing mutations in yeast Dnm1 reveals altered mitochondrial dynamics. Mitochondrion 2021; 59:283-295. [PMID: 34157431 DOI: 10.1016/j.mito.2021.06.009] [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: 03/01/2021] [Revised: 06/14/2021] [Accepted: 06/17/2021] [Indexed: 12/15/2022]
Abstract
The dynamin-related protein 1 (Drp1) and its homologs in various eukaryotes are essential to maintain mitochondrial morphology and regulate mitochondrial division. Several mutations in different domains of Drp1 have been reported, which result in debilitating conditions. Four such disease-causing mutations of the middle domain of Drp1 were mimicked in the yeast dynamin-related GTPase (Dnm1) and were characterized in this study. Mitochondrial morphology and protein function were observed to be altered to a variable extent in cells expressing the mutated variants of Dnm1. Several aspects related to the protein such as punctate formation, localization to mitochondria, dynamic behavior and structure were analyzed by microscopy, biochemical studies and molecular dynamics simulations. Significant effects on the protein structure and function were observed in cells expressing A430D and G397D mutations. Overall, our data provide insight into the molecular and cellular alterations resulting from middle domain mutations in Dnm1.
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Affiliation(s)
- Riddhi Banerjee
- Organelle Biology and Cellular Ageing Lab, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Abhishek Kumar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Priyadarshi Satpati
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Shirisha Nagotu
- Organelle Biology and Cellular Ageing Lab, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India.
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14
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Motta M, Consentino MC, Fontana A, Sciuto L, Falsaperla R, Praticò ER, Salafia S, Zanghì A, Praticò AD. DNM1 Gene and Its Related Epileptic Phenotypes. JOURNAL OF PEDIATRIC NEUROLOGY 2021. [DOI: 10.1055/s-0041-1727258] [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
AbstractThe phenotypic variety associated to mutations in dynamin 1 (DNM1), codifying the presynaptic protein DNM1 has been increasingly reported, mainly related to encephalopathy with intractable epilepsy; currently, it is known the phenotype related to DNM1 gene mutations is relatively homogeneous with developmental delay, hypotonia, and epilepsy characterized by infantile spasms and possible progression to Lennox-Gastaut syndrome. By examining all the papers published until 2020 (18 articles), we compared data from 30 patients (extrapolated from 5 papers) with DNM1 mutations, identifying 26 patients with de novo mutations in DNM1. Nine patients (33.3%) reported the recurrent mutation p.Arg237Trp. A usual phenotype observed comprises severe to deep developmental delay and muscular hypotonia in all patients with epilepsy beginning with infantile spasms, which often evolved into Lennox-Gastaut syndrome. Data about GTPase or central domains mutations, and existing structural modeling and functional suggest a dominant negative effect on DMN1 function. Generally genetic epilepsies consist of a wide spectrum of clinical features, unlike that, DNM1-related CNS impairment phenotype is quite uniform. In up to one third of patients it has been found variant p.Arg237Trp, which is one of the most frequent variant detected in epileptic encephalopathies. The understanding of DNM1 function opens up the chance that this gene would become a new therapeutic target for epilepsies.
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Affiliation(s)
- Milena Motta
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Maria Chiara Consentino
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Alessandra Fontana
- 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
| | - 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
| | | | | | - Antonio Zanghì
- Department of Medical and Surgical Sciences and Advanced Technology “G.F. Ingrassia,” University of Catania, Catania, Italy
| | - Andrea D. Praticò
- Department of Clinical and Experimental Medicine, Unit of Rare Diseases of the Nervous System in Childhood, Section of Pediatrics and Child Neuropsychiatry, University of Catania, Catania, Italy
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15
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John A, Ng-Cordell E, Hanna N, Brkic D, Baker K. The neurodevelopmental spectrum of synaptic vesicle cycling disorders. J Neurochem 2021; 157:208-228. [PMID: 32738165 DOI: 10.1111/jnc.15135] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 07/20/2020] [Accepted: 07/21/2020] [Indexed: 12/11/2022]
Abstract
In this review, we describe and discuss neurodevelopmental phenotypes arising from rare, high penetrance genomic variants which directly influence synaptic vesicle cycling (SVC disorders). Pathogenic variants in each SVC disorder gene lead to disturbance of at least one SVC subprocess, namely vesicle trafficking (e.g. KIF1A and GDI1), clustering (e.g. TRIO, NRXN1 and SYN1), docking and priming (e.g. STXBP1), fusion (e.g. SYT1 and PRRT2) or re-uptake (e.g. DNM1, AP1S2 and TBC1D24). We observe that SVC disorders share a common set of neurological symptoms (movement disorders, epilepsies), cognitive impairments (developmental delay, intellectual disabilities, cerebral visual impairment) and mental health difficulties (autism, ADHD, psychiatric symptoms). On the other hand, there is notable phenotypic variation between and within disorders, which may reflect selective disruption to SVC subprocesses, spatiotemporal and cell-specific gene expression profiles, mutation-specific effects, or modifying factors. Understanding the common cellular and systems mechanisms underlying neurodevelopmental phenotypes in SVC disorders, and the factors responsible for variation in clinical presentations and outcomes, may translate to personalized clinical management and improved quality of life for patients and families.
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Affiliation(s)
- Abinayah John
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
| | - Elise Ng-Cordell
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
| | - Nancy Hanna
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
| | - Diandra Brkic
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
| | - Kate Baker
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
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Savitsky M, Solis GP, Kryuchkov M, Katanaev VL. Humanization of Drosophila Gαo to Model GNAO1 Paediatric Encephalopathies. Biomedicines 2020; 8:E395. [PMID: 33036271 PMCID: PMC7599900 DOI: 10.3390/biomedicines8100395] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 09/30/2020] [Accepted: 10/02/2020] [Indexed: 12/15/2022] Open
Abstract
Several hundred genes have been identified to contribute to epilepsy-the disease affecting 65 million people worldwide. One of these genes is GNAO1 encoding Gαo, the major neuronal α-subunit of heterotrimeric G proteins. An avalanche of dominant de novo mutations in GNAO1 have been recently described in paediatric epileptic patients, suffering, in addition to epilepsy, from motor dysfunction and developmental delay. Although occurring in amino acids conserved from humans to Drosophila, these mutations and their functional consequences have only been poorly analysed at the biochemical or neuronal levels. Adequate animal models to study the molecular aetiology of GNAO1 encephalopathies have also so far been lacking. As the first step towards modeling the disease in Drosophila, we here describe the humanization of the Gαo locus in the fruit fly. A two-step CRISPR/Cas9-mediated replacement was conducted, first substituting the coding exons 2-3 of Gαo with respective human GNAO1 sequences. At the next step, the remaining exons 4-7 were similarly replaced, keeping intact the gene Cyp49a1 embedded in between, as well as the non-coding exons, exon 1 and the surrounding regulatory sequences. The resulting flies, homozygous for the humanized GNAO1 loci, are viable and fertile without any visible phenotypes; their body weight, locomotion, and longevity are also normal. Human Gαo-specific antibodies confirm the endogenous-level expression of the humanized Gαo, which fully replaces the Drosophila functions. The genetic model we established will make it easy to incorporate encephalopathic GNAO1 mutations and will permit intensive investigations into the molecular aetiology of the human disease through the powerful toolkit of Drosophila genetics.
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Affiliation(s)
- Mikhail Savitsky
- Translational Research Center in Oncohaematology, Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, 1211 Geneva, Switzerland; (M.S.); (G.P.S.); (M.K.)
| | - Gonzalo P. Solis
- Translational Research Center in Oncohaematology, Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, 1211 Geneva, Switzerland; (M.S.); (G.P.S.); (M.K.)
| | - Mikhail Kryuchkov
- Translational Research Center in Oncohaematology, Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, 1211 Geneva, Switzerland; (M.S.); (G.P.S.); (M.K.)
| | - Vladimir L. Katanaev
- Translational Research Center in Oncohaematology, Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, 1211 Geneva, Switzerland; (M.S.); (G.P.S.); (M.K.)
- School of Biomedicine, Far Eastern Federal University, 690690 Vladivostok, Russia
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Takai A, Yamaguchi M, Yoshida H, Chiyonobu T. Investigating Developmental and Epileptic Encephalopathy Using Drosophila melanogaster. Int J Mol Sci 2020; 21:ijms21176442. [PMID: 32899411 PMCID: PMC7503973 DOI: 10.3390/ijms21176442] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 08/30/2020] [Accepted: 09/01/2020] [Indexed: 12/16/2022] Open
Abstract
Developmental and epileptic encephalopathies (DEEs) are the spectrum of severe epilepsies characterized by early-onset, refractory seizures occurring in the context of developmental regression or plateauing. Early infantile epileptic encephalopathy (EIEE) is one of the earliest forms of DEE, manifesting as frequent epileptic spasms and characteristic electroencephalogram findings in early infancy. In recent years, next-generation sequencing approaches have identified a number of monogenic determinants underlying DEE. In the case of EIEE, 85 genes have been registered in Online Mendelian Inheritance in Man as causative genes. Model organisms are indispensable tools for understanding the in vivo roles of the newly identified causative genes. In this review, we first present an overview of epilepsy and its genetic etiology, especially focusing on EIEE and then briefly summarize epilepsy research using animal and patient-derived induced pluripotent stem cell (iPSC) models. The Drosophila model, which is characterized by easy gene manipulation, a short generation time, low cost and fewer ethical restrictions when designing experiments, is optimal for understanding the genetics of DEE. We therefore highlight studies with Drosophila models for EIEE and discuss the future development of their practical use.
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Affiliation(s)
- Akari Takai
- Department of Pediatrics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan;
| | - Masamitsu Yamaguchi
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 603-8585, Japan; (M.Y.); (H.Y.)
- Kansai Gakken Laboratory, Kankyo Eisei Yakuhin Co. Ltd., Kyoto 619-0237, Japan
| | - Hideki Yoshida
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 603-8585, Japan; (M.Y.); (H.Y.)
| | - Tomohiro Chiyonobu
- Department of Pediatrics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan;
- Correspondence:
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Velíšek L, Velíšková J. Modeling epileptic spasms during infancy: Are we heading for the treatment yet? Pharmacol Ther 2020; 212:107578. [PMID: 32417271 PMCID: PMC7299814 DOI: 10.1016/j.pharmthera.2020.107578] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 05/07/2020] [Indexed: 12/22/2022]
Abstract
Infantile spasms (IS or epileptic spasms during infancy) were first described by Dr. William James West (aka West syndrome) in his own son in 1841. While rare by definition (occurring in 1 per 3200-3400 live births), IS represent a major social and treatment burden. The etiology of IS varies - there are many (>200) different known pathologies resulting in IS and still in about one third of cases there is no obvious reason. With the advancement of genetic analysis, role of certain genes (such as ARX or CDKL5 and others) in IS appears to be important. Current treatment strategies with incomplete efficacy and serious potential adverse effects include adrenocorticotropin (ACTH), corticosteroids (prednisone, prednisolone) and vigabatrin, more recently also a combination of hormones and vigabatrin. Second line treatments include pyridoxine (vitamin B6) and ketogenic diet. Additional treatment approaches use rapamycin, cannabidiol, valproic acid and other anti-seizure medications. Efficacy of these second line medications is variable but usually inferior to hormonal treatments and vigabatrin. Thus, new and effective models of this devastating condition are required for the search of additional treatment options as well as for better understanding the mechanisms of IS. Currently, eight models of IS are reviewed along with the ideas and mechanisms behind these models, drugs tested using the models and their efficacy and usefulness. Etiological variety of IS is somewhat reflected in the variety of the models. However, it seems that for finding precise personalized approaches, this variety is necessary as there is no "one-size-fits-all" approach possible for both IS in particular and epilepsy in general.
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Affiliation(s)
- Libor Velíšek
- Departments of Cell Biology & Anatomy, New York Medical College, Valhalla, NY, USA; Departments of Pediatrics, New York Medical College, Valhalla, NY, USA; Departments of Neurology, New York Medical College, Valhalla, NY, USA.
| | - Jana Velíšková
- Departments of Cell Biology & Anatomy, New York Medical College, Valhalla, NY, USA; Departments of Neurology, New York Medical College, Valhalla, NY, USA; Departments of Obstetrics & Gynecology, New York Medical College, Valhalla, NY, USA
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Papandreou A, Danti FR, Spaull R, Leuzzi V, Mctague A, Kurian MA. The expanding spectrum of movement disorders in genetic epilepsies. Dev Med Child Neurol 2020; 62:178-191. [PMID: 31784983 DOI: 10.1111/dmcn.14407] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/01/2019] [Indexed: 12/27/2022]
Abstract
An ever-increasing number of neurogenetic conditions presenting with both epilepsy and atypical movements are now recognized. These disorders within the 'genetic epilepsy-dyskinesia' spectrum are clinically and genetically heterogeneous. Increased clinical awareness is therefore necessary for a rational diagnostic approach. Furthermore, careful interpretation of genetic results is key to establishing the correct diagnosis and initiating disease-specific management strategies in a timely fashion. In this review we describe the spectrum of movement disorders associated with genetically determined epilepsies. We also propose diagnostic strategies and putative pathogenic mechanisms causing these complex syndromes associated with both seizures and atypical motor control. WHAT THIS PAPER ADDS: Implicated genes encode proteins with very diverse functions. Pathophysiological mechanisms by which epilepsy and movement disorder phenotypes manifest are often not clear. Early diagnosis of treatable disorders is essential and next generation sequencing may be required.
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Affiliation(s)
- Apostolos Papandreou
- Molecular Neurosciences, Developmental Neurosciences Programme, UCL Great Ormond Street Institute of Child Health, London, UK
- Department of Neurology, Great Ormond Street Hospital, London, UK
| | - Federica Rachele Danti
- Molecular Neurosciences, Developmental Neurosciences Programme, UCL Great Ormond Street Institute of Child Health, London, UK
- Department of Human Neuroscience, Unit of Child Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy
| | - Robert Spaull
- Department of Paediatric Neurology, Bristol Royal Hospital for Children, Bristol, UK
- Bristol Medical School, University of Bristol, Bristol, UK
| | - Vincenzo Leuzzi
- Department of Human Neuroscience, Unit of Child Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy
| | - Amy Mctague
- Molecular Neurosciences, Developmental Neurosciences Programme, UCL Great Ormond Street Institute of Child Health, London, UK
- Department of Neurology, Great Ormond Street Hospital, London, UK
| | - Manju A Kurian
- Molecular Neurosciences, Developmental Neurosciences Programme, UCL Great Ormond Street Institute of Child Health, London, UK
- Department of Neurology, Great Ormond Street Hospital, London, UK
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Li H, Fang F, Xu M, Liu Z, Zhou J, Wang X, Wang X, Han T. Clinical Assessments and EEG Analyses of Encephalopathies Associated With Dynamin-1 Mutation. Front Pharmacol 2019; 10:1454. [PMID: 31920647 PMCID: PMC6915043 DOI: 10.3389/fphar.2019.01454] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 11/13/2019] [Indexed: 12/31/2022] Open
Abstract
Epileptic encephalopathy, caused by mutations in the dynamin-1 (DNM1; NM_004408) gene, is a newly identified neurologic disorder in children. Thus far, the full clinical and electroencephalographic features of children with DNM1 mutation-related epileptic encephalopathy have not been established. The aim of this study is to characterize the phenotypic, genetic, and electroencephalographic features of children with DNM1 mutation-related epileptic encephalopathy. Here, we investigated a patient with a novel pathogenic DNM1 variant, who received treatment in Beijing Children's Hospital and had detailed clinical, EEG, and genetic information. Conversely, we performed an extensive literature search in PubMed, EMBASE, Cochrane Central Register of Controlled Trials, Chinese BioMedical Literature Database, China National Knowledge Infrastructure, and Wanfang Database using the term "DNM1" and were able to find 32 cases reported in nine articles (in English) from January 2013 to December 2018. The clinical features of 33 cases with pathogenic DNM1 variants were analyzed and the results showed that patients carrying pathogenic variants in the GTPase or middle domains present with epileptic encephalopathy and severe neurodevelopmental symptoms. Patients carrying pathogenic variants in both domains exhibited comparable phenotypes.
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Affiliation(s)
- Hua Li
- Department of Neurology, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China
| | - Fang Fang
- Department of Neurology, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China
| | - Manting Xu
- Department of Neurology, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China
| | - Zhimei Liu
- Department of Neurology, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China
| | - Ji Zhou
- Department of Neurology, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China
| | - Xiaohui Wang
- Department of Neurology, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China
| | - Xiaofei Wang
- Department of Neurology, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China
| | - Tongli Han
- Department of Neurology, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China
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21
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Mizuguchi T, Nakashima M, Moey LH, Ch’ng GS, Khoo TB, Mitsuhashi S, Miyatake S, Takata A, Miyake N, Saitsu H, Matsumoto N. A novel homozygous truncating variant of NECAP1 in early infantile epileptic encephalopathy: the second case report of EIEE21. J Hum Genet 2019; 64:347-350. [DOI: 10.1038/s10038-018-0556-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Revised: 12/17/2018] [Accepted: 12/18/2018] [Indexed: 11/09/2022]
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22
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Alsahli S, Al-Twaijri W, Al Mutairi F. Confirming the pathogenicity of NECAP1 in early onset epileptic encephalopathy. Epilepsia Open 2018; 3:524-527. [PMID: 30525121 PMCID: PMC6276780 DOI: 10.1002/epi4.12263] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/18/2018] [Indexed: 12/17/2022] Open
Abstract
Early onset epileptic encephalopathy (EOEE) has been used to encompass Ohtahara syndrome (early infantile epileptic encephalopathy [EIEE]), early myoclonic epilepsy, and many others. Multiple genes have been established to cause epileptic encephalopathy in the immature brain, and next‐generation sequencing has accelerated the process of novel gene discovery. Many of the previously published candidate genes are still pending confirmatory reports or functional studies. Although most of the genes involved are ion channels (channelopathies), multiple other pathways have been implicated as well. NECAP1 is a key element in clathrin‐mediated endocytosis and has been reported previously to cause EOEE in a Saudi family. We report another family with the same variant confirming the pathogenicity of this variant as a Saudi founder mutation, further delineate its phenotype, and propose that it causes EOEE instead of EIEE.
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Affiliation(s)
- Saud Alsahli
- Division of Pediatric Neurology Department of Pediatrics King Abdulaziz Medical City Ministry of National Guard-Health Affairs (MNGHA) Riyadh Saudi Arabia.,King Abdullah International Medical Research Center (KAIMRC) Riyadh Saudi Arabia.,College of Medicine King Saud bin Abdulaziz University for Health Sciences Riyadh Saudi Arabia
| | - Waleed Al-Twaijri
- Division of Pediatric Neurology Department of Pediatrics King Abdulaziz Medical City Ministry of National Guard-Health Affairs (MNGHA) Riyadh Saudi Arabia.,King Abdullah International Medical Research Center (KAIMRC) Riyadh Saudi Arabia.,College of Medicine King Saud bin Abdulaziz University for Health Sciences Riyadh Saudi Arabia
| | - Fuad Al Mutairi
- King Abdullah International Medical Research Center (KAIMRC) Riyadh Saudi Arabia.,College of Medicine King Saud bin Abdulaziz University for Health Sciences Riyadh Saudi Arabia.,Division of Genetics Department of Pediatrics King Abdulaziz Medical City Ministry of National Guard-Health Affairs (MNGHA) Riyadh Saudi Arabia
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23
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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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Luo J, Norris RH, Gordon SL, Nithianantharajah J. Neurodevelopmental synaptopathies: Insights from behaviour in rodent models of synapse gene mutations. Prog Neuropsychopharmacol Biol Psychiatry 2018; 84:424-439. [PMID: 29217145 DOI: 10.1016/j.pnpbp.2017.12.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 11/28/2017] [Accepted: 12/03/2017] [Indexed: 11/15/2022]
Abstract
The genomic revolution has begun to unveil the enormous complexity and heterogeneity of the genetic basis of neurodevelopmental disorders such as such epilepsy, intellectual disability, autism spectrum disorder and schizophrenia. Increasingly, human mutations in synapse genes are being identified across these disorders. These neurodevelopmental synaptopathies highlight synaptic homeostasis pathways as a convergence point underlying disease mechanisms. Here, we review some of the key pre- and postsynaptic genes in which penetrant human mutations have been identified in neurodevelopmental disorders for which genetic rodent models have been generated. Specifically, we focus on the main behavioural phenotypes that have been documented in these animal models, to consolidate our current understanding of how synapse genes regulate key behavioural and cognitive domains. These studies provide insights into better understanding the basis of the overlapping genetic and cognitive heterogeneity observed in neurodevelopmental disorders.
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Affiliation(s)
- J Luo
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria 3052, Australia
| | - R H Norris
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria 3052, Australia
| | - S L Gordon
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria 3052, Australia
| | - J Nithianantharajah
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria 3052, Australia.
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Brereton E, Fassi E, Araujo GC, Dodd J, Telegrafi A, Pathak SJ, Shinawi M. Mutations in the PH Domain of DNM1 are associated with a nonepileptic phenotype characterized by developmental delay and neurobehavioral abnormalities. Mol Genet Genomic Med 2018; 6:294-300. [PMID: 29397573 PMCID: PMC5902389 DOI: 10.1002/mgg3.362] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2017] [Revised: 11/13/2017] [Accepted: 11/15/2017] [Indexed: 11/30/2022] Open
Abstract
Background Dynamin 1 is a protein involved in the synaptic vesicle cycle, which facilitates the exocytosis of neurotransmitters necessary for normal signaling and development in the central nervous system. Pathogenic variants in DNM1 have been implicated in global developmental delay (DD), severe intellectual disability (ID), and notably, epileptic encephalopathy. All previously reported DNM1 pathogenic variants causing this severe phenotype occur in the GTPase and Middle domains of the dynamin 1 protein. Methods We used whole‐exome sequencing to characterize the molecular basis of DD and autistic symptoms in two identical siblings. Results The twin siblings exhibit mild to moderate ID and autistic symptoms but no epileptic encephalopathy. Exome sequencing revealed a genetic variant, c.1603A>G (p.Lys535Glu), in the PH domain of dynamin 1. Previous in vitro studies showed that mutations at Lys535 inhibit endocytosis and impair PH loop binding to PIP2. Conclusions Our data suggest a previously undescribed milder phenotype associated with a missense genetic variant in the PH domain of dynamin 1.
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Affiliation(s)
- Emily Brereton
- Washington University School of Medicine, St. Louis, MO, USA
| | - Emily Fassi
- Division of Genetics and Genomic Medicine, Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, USA
| | - Gabriel C Araujo
- Department of Psychology, St Louis Children's Hospital, St. Louis, MO, USA
| | - Jonathan Dodd
- Department of Psychology, St Louis Children's Hospital, St. Louis, MO, USA
| | | | - Sheel J Pathak
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
| | - Marwan Shinawi
- Washington University School of Medicine, St. Louis, MO, USA.,Division of Genetics and Genomic Medicine, Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, USA
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26
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Shimojima K, Okamoto N, Goel H, Ondo Y, Yamamoto T. Familial 9q33q34 microduplication in siblings with developmental disorders and macrocephaly. Eur J Med Genet 2017; 60:650-654. [PMID: 28899818 DOI: 10.1016/j.ejmg.2017.08.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 08/28/2017] [Accepted: 08/29/2017] [Indexed: 10/18/2022]
Abstract
Because several genes responsible for epileptic encephalopathy are located on the 9q33q34 region, patients with chromosomal deletions of this region often show intractable epilepsy and neurodevelopmental disability. Contrary to these findings, chromosomal duplications of this region have never been reported previously. We identified a first case of 9q33q34 microduplications in siblings associated with developmental disorders and macrocephaly. Their mother was a mosaic carrier of this duplication. Duplicated regions involved STXBP1; the gene related to epileptic encephalopathy. Neurological features including developmental delay and macrocephaly observed in the present siblings may be derived from the extra-copy of STXBP1.
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Affiliation(s)
- Keiko Shimojima
- Institute of Medical Genetics, Tokyo Women's Medical University, Tokyo, Japan
| | - Nobuhiko Okamoto
- Department of Medical Genetics, Osaka Women's and Children's Hospital, Osaka, Japan
| | - Himanshu Goel
- School of Medicine and Public Health, Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW, Australia
| | - Yumiko Ondo
- Institute of Medical Genetics, Tokyo Women's Medical University, Tokyo, Japan
| | - Toshiyuki Yamamoto
- Institute of Medical Genetics, Tokyo Women's Medical University, Tokyo, Japan.
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27
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Jean F, Pilgrim D. Coordinating the uncoordinated: UNC119 trafficking in cilia. Eur J Cell Biol 2017; 96:643-652. [PMID: 28935136 DOI: 10.1016/j.ejcb.2017.09.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 08/25/2017] [Accepted: 09/05/2017] [Indexed: 12/29/2022] Open
Abstract
Constructing the distinct subcellular environment of the cilium relies in a large part upon intraflagellar transport (IFT) proteins, which traffic cargo both to and within the cilium. However, evidence from the last 10 years suggests that IFT alone is not sufficient to generate the ciliary environment. One essential factor is UNC119, which interacts with known IFT molecular switches to transport ciliary cargos. Despite its apparent importance in ciliary trafficking though, human UNC119 mutations have only rarely been associated with diseases commonly linked with ciliopathies. This review will outline the trafficking pathways required for constructing the cilium by highlighting UNC119's role and the complexities involved in ciliary trafficking. Finally, despite important roles for UNC119 in cilia, UNC119 proteins also interact with non-ciliary proteins to affect other cellular processes.
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28
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Fahrner JA, Liu R, Perry MS, Klein J, Chan DC. A novel de novo dominant negative mutation in DNM1L impairs mitochondrial fission and presents as childhood epileptic encephalopathy. Am J Med Genet A 2016; 170:2002-11. [PMID: 27145208 DOI: 10.1002/ajmg.a.37721] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 04/17/2016] [Indexed: 11/07/2022]
Abstract
DNM1L encodes dynamin-related protein 1 (DRP1/DLP1), a key component of the mitochondrial fission machinery that is essential for proper functioning of the mammalian brain. Previously reported probands with de novo missense mutations in DNM1L presented in the first year of life with severe encephalopathy and refractory epilepsy, with several dying within the first several weeks after birth. In contrast, we report identical novel missense mutations in DNM1L in two unrelated probands who experienced normal development for several years before presenting with refractory focal status epilepticus and subsequent rapid neurological decline. We expand the phenotype of DNM1L-related mitochondrial fission defects, reveal common unique clinical characteristics and imaging findings, and compare the cellular impact of this novel mutation to the previously reported A395D lethal variant. We demonstrate that our R403C mutation, which resides in the assembly region of DRP1, acts by a dominant-negative mechanism and reduces oligomerization, mitochondrial fission activity, and mitochondrial recruitment of DRP1, but to a lesser extent compared to the A395D mutation. In contrast to the initial report of neonatal lethality resulting from DNM1L mutation and DRP1 dysfunction, our results show that milder DRP1 impairment is compatible with normal early development and subsequently results in a distinct set of neurological findings. In addition, we identify a common pathogenic mechanism whereby DNM1L mutations impair mitochondrial fission. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Jill A Fahrner
- Department of Pediatrics, McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Raymond Liu
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California
| | - Michael Scott Perry
- Comprehensive Epilepsy Program, Jane and John Justin Neuroscience Center, Cook Children's Medical Center, Fort Worth, Texas
| | - Jessica Klein
- Division of Pediatric Neurology, Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland.,Department of Pediatrics, Medical University of South Carolina, Charleston, South Carolina
| | - David C Chan
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California
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