1
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Sert O, Ding X, Zhang C, Mi R, Hoke A, Rasband MN. Postsynaptic β1 spectrin maintains Na + channels at the neuromuscular junction. J Physiol 2024; 602:1127-1145. [PMID: 38441922 PMCID: PMC10942750 DOI: 10.1113/jp285894] [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: 11/01/2023] [Accepted: 02/13/2024] [Indexed: 03/16/2024] Open
Abstract
Spectrins function together with actin as obligatory subunits of the submembranous cytoskeleton. Spectrins maintain cell shape, resist mechanical forces, and stabilize ion channel and transporter protein complexes through binding to scaffolding proteins. Recently, pathogenic variants of SPTBN4 (β4 spectrin) were reported to cause both neuropathy and myopathy. Although the role of β4 spectrin in neurons is mostly understood, its function in skeletal muscle, another excitable tissue subject to large forces, is unknown. Here, using a muscle specific β4 spectrin conditional knockout mouse, we show that β4 spectrin does not contribute to muscle function. In addition, we show β4 spectrin is not present in muscle, indicating the previously reported myopathy associated with pathogenic SPTBN4 variants is neurogenic in origin. More broadly, we show that α2, β1 and β2 spectrins are found in skeletal muscle, with α2 and β1 spectrins being enriched at the postsynaptic neuromuscular junction (NMJ). Surprisingly, using muscle specific conditional knockout mice, we show that loss of α2 and β2 spectrins had no effect on muscle health, function or the enrichment of β1 spectrin at the NMJ. Muscle specific deletion of β1 spectrin also had no effect on muscle health, but, with increasing age, resulted in the loss of clustered NMJ Na+ channels. Together, our results suggest that muscle β1 spectrin functions independently of an associated α spectrin to maintain Na+ channel clustering at the postsynaptic NMJ. Furthermore, despite repeated exposure to strong forces and in contrast to neurons, muscles do not require spectrin cytoskeletons to maintain cell shape or integrity. KEY POINTS: The myopathy found in pathogenic human SPTBN4 variants (where SPTBN4 is the gene encoding β4 spectrin) is neurogenic in origin. β1 spectrin plays essential roles in maintaining the density of neuromuscular junction Nav1.4 Na+ channels. By contrast to the canonical view of spectrin organization and function, we show that β1 spectrin can function independently of an associated α spectrin. Despite the large mechanical forces experienced by muscle, we show that spectrins are not required for muscle cell integrity. This is in stark contrast to red blood cells and the axons of neurons.
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Affiliation(s)
- Ozlem Sert
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA 77030
| | - Xiaoyun Ding
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA 77030
| | - Chuansheng Zhang
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA 77030
| | - Ruifa Mi
- Departments of Neurology and Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD 21205
| | - Ahmet Hoke
- Departments of Neurology and Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD 21205
| | - Matthew N. Rasband
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA 77030
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2
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Ahmed T, Ramonett A, Kwak EA, Kumar S, Flores PC, Ortiz HR, Langlais PR, Hund TJ, Mythreye K, Lee NY. Endothelial tip/stalk cell selection requires BMP9-induced β IV-spectrin expression during sprouting angiogenesis. Mol Biol Cell 2023; 34:ar72. [PMID: 37126382 PMCID: PMC10295478 DOI: 10.1091/mbc.e23-02-0064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 04/14/2023] [Accepted: 04/19/2023] [Indexed: 05/02/2023] Open
Abstract
βIV-Spectrin is a membrane cytoskeletal protein with specialized roles in the nervous system and heart. Recent evidence also indicates a fundamental role for βIV-spectrin in angiogenesis as its endothelial-specific gene deletion in mice enhances embryonic lethality due to hypervascularization and hemorrhagic defects. During early vascular sprouting, βIV-spectrin is believed to inhibit tip cell sprouting in favor of the stalk cell phenotype by mediating VEGFR2 internalization and degradation. Despite these essential roles, mechanisms governing βIV-spectrin expression remain unknown. Here we identify bone morphogenetic protein 9 (BMP9) as a major inducer of βIV-spectrin gene expression in the vascular system. We show that BMP9 signals through the ALK1/Smad1 pathway to induce βIV-spectrin expression, which then recruits CaMKII to the cell membrane to induce phosphorylation-dependent VEGFR2 turnover. Although BMP9 signaling promotes stalk cell behavior through activation of hallmark stalk cell genes ID-1/3 and Hes-1 and Notch signaling cross-talk, we find that βIV-spectrin acts upstream of these pathways as loss of βIV-spectrin in neonate mice leads to retinal hypervascularization due to excessive VEGFR2 levels, increased tip cell populations, and strong Notch inhibition irrespective of BMP9 treatment. These findings demonstrate βIV-spectrin as a BMP9 gene target critical for tip/stalk cell selection during nascent vessel sprouting.
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Affiliation(s)
- Tasmia Ahmed
- Department of Chemistry & Biochemistry, University of Arizona, Tucson, AZ 85724
| | - Aaron Ramonett
- Department of Pharmacology, University of Arizona, Tucson, AZ 85724
| | - Eun-A Kwak
- Department of Pharmacology, University of Arizona, Tucson, AZ 85724
| | - Sanjay Kumar
- Division of Biology, Indian Institute of Science Education and Research, Tirupati 517507, India
| | - Paola Cruz Flores
- Department of Chemistry & Biochemistry, University of Arizona, Tucson, AZ 85724
| | - Hannah R. Ortiz
- Department of Pharmacology, University of Arizona, Tucson, AZ 85724
| | | | - Thomas J. Hund
- Department of Biomedical Engineering, Ohio State University, Columbus, OH 43210
| | - Karthikeyan Mythreye
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Nam Y. Lee
- Department of Chemistry & Biochemistry, University of Arizona, Tucson, AZ 85724
- Department of Pharmacology, University of Arizona, Tucson, AZ 85724
- Comprehensive Cancer Center, University of Arizona, Tucson, AZ 85724
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3
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Garrido JJ. Contribution of Axon Initial Segment Structure and Channels to Brain Pathology. Cells 2023; 12:cells12081210. [PMID: 37190119 DOI: 10.3390/cells12081210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 04/17/2023] [Accepted: 04/20/2023] [Indexed: 05/17/2023] Open
Abstract
Brain channelopathies are a group of neurological disorders that result from genetic mutations affecting ion channels in the brain. Ion channels are specialized proteins that play a crucial role in the electrical activity of nerve cells by controlling the flow of ions such as sodium, potassium, and calcium. When these channels are not functioning properly, they can cause a wide range of neurological symptoms such as seizures, movement disorders, and cognitive impairment. In this context, the axon initial segment (AIS) is the site of action potential initiation in most neurons. This region is characterized by a high density of voltage-gated sodium channels (VGSCs), which are responsible for the rapid depolarization that occurs when the neuron is stimulated. The AIS is also enriched in other ion channels, such as potassium channels, that play a role in shaping the action potential waveform and determining the firing frequency of the neuron. In addition to ion channels, the AIS contains a complex cytoskeletal structure that helps to anchor the channels in place and regulate their function. Therefore, alterations in this complex structure of ion channels, scaffold proteins, and specialized cytoskeleton may also cause brain channelopathies not necessarily associated with ion channel mutations. This review will focus on how the AISs structure, plasticity, and composition alterations may generate changes in action potentials and neuronal dysfunction leading to brain diseases. AIS function alterations may be the consequence of voltage-gated ion channel mutations, but also may be due to ligand-activated channels and receptors and AIS structural and membrane proteins that support the function of voltage-gated ion channels.
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Affiliation(s)
- Juan José Garrido
- Instituto Cajal, CSIC, 28002 Madrid, Spain
- Alzheimer's Disease and Other Degenerative Dementias, Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), 28002 Madrid, Spain
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4
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Lorenzo DN, Edwards RJ, Slavutsky AL. Spectrins: molecular organizers and targets of neurological disorders. Nat Rev Neurosci 2023; 24:195-212. [PMID: 36697767 PMCID: PMC10598481 DOI: 10.1038/s41583-022-00674-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/22/2022] [Indexed: 01/26/2023]
Abstract
Spectrins are cytoskeletal proteins that are expressed ubiquitously in the mammalian nervous system. Pathogenic variants in SPTAN1, SPTBN1, SPTBN2 and SPTBN4, four of the six genes encoding neuronal spectrins, cause neurological disorders. Despite their structural similarity and shared role as molecular organizers at the cell membrane, spectrins vary in expression, subcellular localization and specialization in neurons, and this variation partly underlies non-overlapping disease presentations across spectrinopathies. Here, we summarize recent progress in discerning the local and long-range organization and diverse functions of neuronal spectrins. We provide an overview of functional studies using mouse models, which, together with growing human genetic and clinical data, are helping to illuminate the aetiology of neurological spectrinopathies. These approaches are all critical on the path to plausible therapeutic solutions.
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Affiliation(s)
- Damaris N Lorenzo
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
| | - Reginald J Edwards
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Anastasia L Slavutsky
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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Progressive Ataxia, Memory Impairments, and Seizure Episodes in Spna2 R1098Q Mouse Variant Affecting Alpha II Spectrin's Scaffold Stability. Brain Sci 2023; 13:brainsci13020261. [PMID: 36831804 PMCID: PMC9953789 DOI: 10.3390/brainsci13020261] [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] [Received: 01/03/2023] [Revised: 01/25/2023] [Accepted: 01/30/2023] [Indexed: 02/09/2023] Open
Abstract
SPTAN1 spectrinopathies refer to a group of rare, inherited diseases associated with damage to non-erythrocytic α-II spectrin (α-II). They are linked to a range of mild to severe neuropathologies of the central and peripheral nervous systems, such as early infantile epileptic encephalopathy type 5, cerebellar ataxia, inherited peripheral neuropathy, and spastic paraplegia. Modeling human SPTAN1 encephalopathies in laboratory animals has been challenging partially because no haploinsufficiency-related phenotypes unfold in heterozygous Spna2 deficient mice nor stable transgenic lines of mice mimicking missense human SPTAN1 mutations have been created to date. Here, we assess the motor and memory performance of a dominant-negative murine Spna2 (SPTAN1) variant carrying a spontaneous point mutation replacing an arginine 1098 in the repeat 10th of α-II with the glutamine (R1098Q). By comparing groups of heterozygous R1098Q mice at different ages, we find evidence for progressive ataxia, and age-related deterioration of motor performance and muscle strength. We also document stress-induced, long-lasting seizure episodes of R1098Q mice and their poor performance in novel object recognition memory tests. Overall, we propose that the complexity of neuropathology-related phenotypes presented by the R1098Q mice recapitulates a number of symptoms observed in human patients carrying SPTAN1 mutations affecting α-II scaffold stability. This makes the R1098Q mice a valuable animal model for preclinical research.
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Dziadkowiak E, Nowakowska-Kotas M, Budrewicz S, Koszewicz M. Pathology of Initial Axon Segments in Chronic Inflammatory Demyelinating Polyradiculoneuropathy and Related Disorders. Int J Mol Sci 2022; 23:13621. [PMID: 36362407 PMCID: PMC9658771 DOI: 10.3390/ijms232113621] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 10/27/2022] [Accepted: 11/01/2022] [Indexed: 07/30/2023] Open
Abstract
The diagnosis of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is based on a combination of clinical, electrodiagnostic and laboratory features. The different entities of the disease include chronic immune sensory polyradiculopathy (CISP) and autoimmune nodopathies. It is debatable whether CIDP occurring in the course of other conditions, i.e., monoclonal IgG or IgA gammopathy, should be treated as a separate disease entity from idiopathic CIDP. This study aims to evaluate the molecular differences of the nodes of Ranvier and the initial axon segment (AIS) and juxtaparanode region (JXP) as the potential cause of phenotypic variation of CIDP while also seeking new pathomechanisms since JXP is sequestered behind the paranode and autoantibodies may not access the site easily. The authors initially present the structure of the different parts of the neuron and its functional significance, then discuss the problem of whether damage to the juxtaparanodal region, Schwann cells and axons could cause CIDP or if these damages should be separated as separate disease entities. In particular, AIS's importance for modulating neural excitability and carrying out transport along the axon is highlighted. The disclosure of specific pathomechanisms, including novel target antigens, in the heterogeneous CIDP syndrome is important for diagnosing and treating these patients.
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Beijer D, Züchner SL. Commentary: SPTBN5, encoding the βV-spectrin protein, leads to a syndrome of intellectual disability, developmental delay, and seizures. Front Mol Neurosci 2022; 15:1011856. [PMID: 36117916 PMCID: PMC9478934 DOI: 10.3389/fnmol.2022.1011856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 08/18/2022] [Indexed: 11/13/2022] Open
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8
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Li S, Liu T, Li K, Bai X, Xi K, Chai X, Mi L, Li J. Spectrins and human diseases. Transl Res 2022; 243:78-88. [PMID: 34979321 DOI: 10.1016/j.trsl.2021.12.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 12/27/2021] [Accepted: 12/28/2021] [Indexed: 11/18/2022]
Abstract
Spectrin, as one of the major components of a plasma membrane-associated cytoskeleton, is a cytoskeletal protein composed of the modular structure of α and β subunits. The spectrin-based skeleton is essential for preserving the integrity and mechanical characteristics of the cell membrane. Moreover, spectrin regulates a variety of cell processes including cell apoptosis, cell adhesion, cell spreading, and cell cycle. Dysfunction of spectrins is implicated in various human diseases including hemolytic anemia, neurodegenerative diseases, ataxia, heart diseases, and cancers. Here, we briefly discuss spectrins function as well as the clinical manifestations and currently known molecular mechanisms of human diseases related to spectrins, highlighting that strategies for targeting regulation of spectrins function may provide new avenues for therapeutic intervention for these diseases.
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Affiliation(s)
- Shan Li
- The First School of Clinical Medicine, Lanzhou University, Gansu, China
| | - Ting Liu
- The First School of Clinical Medicine, Lanzhou University, Gansu, China
| | - Kejing Li
- The First School of Clinical Medicine, Lanzhou University, Gansu, China
| | - Xinyi Bai
- The First School of Clinical Medicine, Lanzhou University, Gansu, China
| | - Kewang Xi
- The First School of Clinical Medicine, Lanzhou University, Gansu, China
| | - Xiaojing Chai
- Central Laboratory, The First Hospital of Lanzhou University, Gansu, China
| | - Leyuan Mi
- The First School of Clinical Medicine, Lanzhou University, Gansu, China; Clinical Laboratory Center, Gansu Provincial Maternity and Child Care Hospital, Gansu, China
| | - Juan Li
- Gansu Key Laboratory of Genetic Study of Hematopathy, The First Hospital of Lanzhou University, Gansu, China; Central Laboratory, The First Hospital of Lanzhou University, Gansu, China.
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9
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Loss of β4-spectrin impairs Na v channel clustering at the heminode and temporal fidelity of presynaptic spikes in developing auditory brain. Sci Rep 2022; 12:5854. [PMID: 35393465 PMCID: PMC8991253 DOI: 10.1038/s41598-022-09856-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 03/15/2022] [Indexed: 01/21/2023] Open
Abstract
Beta-4 (β4)-spectrin, encoded by the gene Sptbn4, is a cytoskeleton protein found at nodes and the axon initial segments (AIS). Sptbn4 mutations are associated with myopathy, neuropathy, and auditory deficits in humans. Related to auditory dysfunction, however, the expression and roles of β4-spectrin at axon segments along the myelinated axon in the developing auditory brain are not well explored. We found during postnatal development, β4-spectrin is critical for voltage-gated sodium channel (Nav) clustering at the heminode along the nerve terminal, but not for the formation of nodal and AIS structures in the auditory brainstem. Presynaptic terminal recordings in Sptbn4geo mice, β4-spectrin null mice, showed an elevated threshold of action potential and increased failures during action potential train at high-frequency. Sptbn4geo mice exhibited a slower central conduction and showed no startle responses, but had normal cochlear function. Taken together, the lack of β4-spectrin impairs Nav clustering at the heminode along the nerve terminal and the temporal fidelity and reliability of presynaptic spikes, leading to central auditory processing deficits during postnatal development.
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10
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Molecular Diagnostic Outcomes from 700 Cases: What Can We Learn from a Retrospective Analysis of Clinical Exome Sequencing? J Mol Diagn 2022; 24:274-286. [PMID: 35065284 PMCID: PMC9904168 DOI: 10.1016/j.jmoldx.2021.12.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 11/29/2021] [Accepted: 12/10/2021] [Indexed: 01/19/2023] Open
Abstract
Clinical exome sequencing (CES) aids in the diagnosis of rare genetic disorders. Herein, we report the molecular diagnostic yield and spectrum of genetic alterations contributing to disease in 700 pediatric cases analyzed at the Children's Hospital of Philadelphia. The overall diagnostic yield was 23%, with three cases having more than one molecular diagnosis and 2.6% having secondary/additional findings. A candidate gene finding was reported in another 8.4% of cases. The clinical indications with the highest diagnostic yield were neurodevelopmental disorders (including seizures), whereas immune- and oncology-related indications were negatively associated with molecular diagnosis. The rapid expansion of knowledge regarding the genome's role in human disease necessitates reanalysis of CES samples. To capture these new discoveries, a subset of cases (n = 240) underwent reanalysis, with an increase in diagnostic yield. We describe our experience reporting CES results in a pediatric setting, including reporting of secondary findings, reporting newly discovered genetic conditions, and revisiting negative test results. Finally, we highlight the challenges associated with implementing critical updates to the CES workflow. Although these updates are necessary, they demand an investment of time and resources from the laboratory. In summary, these data demonstrate the clinical utility of exome sequencing and reanalysis, while highlighting the critical considerations for continuous improvement of a CES test in a clinical laboratory.
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11
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Van de Vondel L, De Winter J, Beijer D, Coarelli G, Wayand M, Palvadeau R, Pauly MG, Klein K, Rautenberg M, Guillot-Noël L, Deconinck T, Vural A, Ertan S, Dogu O, Uysal H, Brankovic V, Herzog R, Brice A, Durr A, Klebe S, Stock F, Bischoff AT, Rattay TW, Sobrido MJ, De Michele G, De Jonghe P, Klopstock T, Lohmann K, Zanni G, Santorelli FM, Timmerman V, Haack TB, Züchner S, Schüle R, Stevanin G, Synofzik M, Basak AN, Baets J. De Novo and Dominantly Inherited SPTAN1 Mutations Cause Spastic Paraplegia and Cerebellar Ataxia. Mov Disord 2022; 37:1175-1186. [PMID: 35150594 DOI: 10.1002/mds.28959] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 01/18/2022] [Accepted: 01/20/2022] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Pathogenic variants in SPTAN1 have been linked to a remarkably broad phenotypical spectrum. Clinical presentations include epileptic syndromes, intellectual disability, and hereditary motor neuropathy. OBJECTIVES We investigated the role of SPTAN1 variants in rare neurological disorders such as ataxia and spastic paraplegia. METHODS We screened 10,000 NGS datasets across two international consortia and one local database, indicative of the level of international collaboration currently required to identify genes causative for rare disease. We performed in silico modeling of the identified SPTAN1 variants. RESULTS We describe 22 patients from 14 families with five novel SPTAN1 variants. Of six patients with cerebellar ataxia, four carry a de novo SPTAN1 variant and two show a sporadic inheritance. In this group, one variant (p.Lys2083del) is recurrent in four patients. Two patients have novel de novo missense mutations (p.Arg1098Cys, p.Arg1624Cys) associated with cerebellar ataxia, in one patient accompanied by intellectual disability and epilepsy. We furthermore report a recurrent missense mutation (p.Arg19Trp) in 15 patients with spastic paraplegia from seven families with a dominant inheritance pattern in four and a de novo origin in one case. One further patient carrying a de novo missense mutation (p.Gln2205Pro) has a complex spastic ataxic phenotype. Through protein modeling we show that mutated amino acids are located at crucial interlinking positions, interconnecting the three-helix bundle of a spectrin repeat. CONCLUSIONS We show that SPTAN1 is a relevant candidate gene for ataxia and spastic paraplegia. We suggest that for the mutations identified in this study, disruption of the interlinking of spectrin helices could be a key feature of the pathomechanism. © 2022 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Liedewei Van de Vondel
- Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium.,Laboratory of Neuromuscular Pathology, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium
| | - Jonathan De Winter
- Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium.,Laboratory of Neuromuscular Pathology, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium.,Neuromuscular Reference Centre, Department of Neurology, Antwerp University Hospital, Antwerp, Belgium
| | - Danique Beijer
- Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium.,Laboratory of Neuromuscular Pathology, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium.,Dr John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Giulia Coarelli
- Sorbonne University, ICM-Paris Brain Institute, INSERM, CNRS, APHP, Pitié Salpêtrière Hospital, Paris, France
| | - Melanie Wayand
- Department of Neurodegenerative Diseases, Hertie Institute for Clinical Brain Research (HIH), Center of Neurology, University of Tübingen, Tübingen, Germany.,German Center for Neurodegenerative Diseases (DZNE), University of Tübingen, Tübingen, Germany
| | - Robin Palvadeau
- Koc University, School of Medicine, Suna and Inan Kirac Foundation, Istanbul, Turkey
| | - Martje G Pauly
- Department of Neurology, University Hospital Schleswig Holstein, Lübeck, Germany.,Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | - Katrin Klein
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Tübingen, Germany
| | - Maren Rautenberg
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Tübingen, Germany
| | - Léna Guillot-Noël
- Sorbonne University, ICM-Paris Brain Institute, INSERM, CNRS, APHP, Pitié Salpêtrière Hospital, Paris, France
| | - Tine Deconinck
- Center of Medical Genetics, University of Antwerp and Antwerp University Hospital, Edegem, Belgium
| | - Atay Vural
- School of Medicine, Department of Neurology, Koc University, Istanbul, Turkey
| | - Sibel Ertan
- School of Medicine, Department of Neurology, Koc University, Istanbul, Turkey
| | - Okan Dogu
- Department of Neurology, School of Medicine, Mersin University, Mersin, Turkey
| | - Hilmi Uysal
- Department of Neurology, School of Medicine, Akdeniz University, Antalya, Turkey
| | - Vesna Brankovic
- Clinic for Child Neurology and Psychiatry, University of Belgrade, Belgrade, Serbia
| | - Rebecca Herzog
- Department of Neurology, University Hospital Schleswig Holstein, Lübeck, Germany
| | - Alexis Brice
- Sorbonne University, ICM-Paris Brain Institute, INSERM, CNRS, APHP, Pitié Salpêtrière Hospital, Paris, France
| | - Alexandra Durr
- Sorbonne University, ICM-Paris Brain Institute, INSERM, CNRS, APHP, Pitié Salpêtrière Hospital, Paris, France
| | - Stephan Klebe
- Department of Neurology, University Hospital Essen, Essen, Germany
| | - Friedrich Stock
- Institute of Human Genetics, University Hospital Essen, Essen, Germany
| | | | - Tim W Rattay
- Department of Neurodegenerative Diseases, Hertie Institute for Clinical Brain Research (HIH), Center of Neurology, University of Tübingen, Tübingen, Germany.,German Center for Neurodegenerative Diseases (DZNE), University of Tübingen, Tübingen, Germany
| | - María-Jesús Sobrido
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Santiago de Compostela, Spain.,Neurogenetics Research Group, Instituto de Investigación Sanitaria (IDIS), Hospital Clínico Universitario, SERGAS, Santiago de Compostela, Spain
| | - Giovanna De Michele
- Department of Neurosciences and Reproductive and Odontostomatological Sciences, Federico II University, Naples, Italy
| | - Peter De Jonghe
- Laboratory of Neuromuscular Pathology, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium.,Neuromuscular Reference Centre, Department of Neurology, Antwerp University Hospital, Antwerp, Belgium
| | - Thomas Klopstock
- Department of Neurology, Friedrich-Baur-Institute, LMU Munich, Munich, Germany.,German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Katja Lohmann
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | - Ginevra Zanni
- Unit of Neuromuscular and Neurodegenerative Disorders, Department of Neurosciences, Bambino Gesù Children's Hospital, Rome, Italy
| | | | - Vincent Timmerman
- Laboratory of Neuromuscular Pathology, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium.,Peripheral Neuropathy Research Group, Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
| | - Tobias B Haack
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Tübingen, Germany.,Centre for Rare Diseases, University of Tübingen, Tübingen, Germany
| | - Stephan Züchner
- Dr John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, USA
| | | | - Rebecca Schüle
- Department of Neurodegenerative Diseases, Hertie Institute for Clinical Brain Research (HIH), Center of Neurology, University of Tübingen, Tübingen, Germany.,German Center for Neurodegenerative Diseases (DZNE), University of Tübingen, Tübingen, Germany
| | - Giovanni Stevanin
- Sorbonne University, ICM-Paris Brain Institute, INSERM, CNRS, APHP, Pitié Salpêtrière Hospital, Paris, France.,Paris Sciences Lettres Research University, Ecole Pratique des Hautes Etudes, Paris, France
| | - Matthis Synofzik
- Department of Neurodegenerative Diseases, Hertie Institute for Clinical Brain Research (HIH), Center of Neurology, University of Tübingen, Tübingen, Germany.,German Center for Neurodegenerative Diseases (DZNE), University of Tübingen, Tübingen, Germany
| | - A Nazli Basak
- Koc University, School of Medicine, Suna and Inan Kirac Foundation, Istanbul, Turkey
| | - Jonathan Baets
- Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium.,Laboratory of Neuromuscular Pathology, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium.,Neuromuscular Reference Centre, Department of Neurology, Antwerp University Hospital, Antwerp, Belgium
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Liang F, Fu X, Ding S, Li L. Use of a Network-Based Method to Identify Latent Genes Associated with Hearing Loss in Children. Front Cell Dev Biol 2021; 9:783500. [PMID: 34912812 PMCID: PMC8667072 DOI: 10.3389/fcell.2021.783500] [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: 09/26/2021] [Accepted: 11/15/2021] [Indexed: 11/13/2022] Open
Abstract
Hearing loss is a total or partial inability to hear. Approximately 5% of people worldwide experience this condition. Hearing capacity is closely related to language, social, and basic emotional development; hearing loss is particularly serious in children. The pathogenesis of childhood hearing loss remains poorly understood. Here, we sought to identify new genes potentially associated with two types of hearing loss in children: congenital deafness and otitis media. We used a network-based method incorporating a random walk with restart algorithm, as well as a protein-protein interaction framework, to identify genes potentially associated with either pathogenesis. A following screening procedure was performed and 18 and 87 genes were identified, which potentially involved in the development of congenital deafness or otitis media, respectively. These findings provide novel biomarkers for clinical screening of childhood deafness; they contribute to a genetic understanding of the pathogenetic mechanisms involved.
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Affiliation(s)
- Feng Liang
- Anaesthesia Department, China-Japan Union Hospital, JiLin University, Changchun, China
| | - Xin Fu
- Anaesthesia Department, China-Japan Union Hospital, JiLin University, Changchun, China
| | - ShiJian Ding
- School of Life Sciences, Shanghai University, Shanghai, China
| | - Lin Li
- Department of Otorhinolaryngology Head and Neck Surgery, China-Japan Union Hospital of Jilin University, Changchun, China
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13
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Zhang C, Joshi A, Liu Y, Sert O, Haddix SG, Teliska LH, Rasband A, Rodney GG, Rasband MN. Ankyrin-dependent Na + channel clustering prevents neuromuscular synapse fatigue. Curr Biol 2021; 31:3810-3819.e4. [PMID: 34289389 DOI: 10.1016/j.cub.2021.06.052] [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] [Received: 04/07/2021] [Revised: 06/09/2021] [Accepted: 06/17/2021] [Indexed: 01/18/2023]
Abstract
Skeletal muscle contraction depends on activation of clustered acetylcholine receptors (AchRs) and muscle-specific Na+ channels (Nav1.4). Some Nav1.4 channels are highly enriched at the neuromuscular junction (NMJ), and their clustering is thought to be essential for effective muscle excitation. However, this has not been experimentally tested, and how NMJ Na+ channels are clustered is unknown. Here, using muscle-specific ankyrinR, ankyrinB, and ankyrinG single, double, and triple-conditional knockout mice, we show that Nav1.4 channels fail to cluster only after deletion of all three ankyrins. Remarkably, ankyrin-deficient muscles have normal NMJ morphology, AchR clustering, sarcolemmal levels of Nav1.4, and muscle force, and they show no indication of degeneration. However, mice lacking clustered NMJ Na+ channels have significantly reduced levels of motor activity and their NMJs rapidly fatigue after repeated nerve-dependent stimulation. Thus, the triple redundancy of ankyrins facilitates NMJ Na+ channel clustering to prevent neuromuscular synapse fatigue.
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Affiliation(s)
- Chuansheng Zhang
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Abhijeet Joshi
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Yanhong Liu
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ozlem Sert
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Seth G Haddix
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Lindsay H Teliska
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Anne Rasband
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - George G Rodney
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Matthew N Rasband
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA.
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14
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Fujitani M, Otani Y, Miyajima H. Pathophysiological Roles of Abnormal Axon Initial Segments in Neurodevelopmental Disorders. Cells 2021; 10:2110. [PMID: 34440880 PMCID: PMC8392614 DOI: 10.3390/cells10082110] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/13/2021] [Accepted: 08/15/2021] [Indexed: 11/17/2022] Open
Abstract
The 20-60 μm axon initial segment (AIS) is proximally located at the interface between the axon and cell body. AIS has characteristic molecular and structural properties regulated by the crucial protein, ankyrin-G. The AIS contains a high density of Na+ channels relative to the cell body, which allows low thresholds for the initiation of action potential (AP). Molecular and physiological studies have shown that the AIS is also a key domain for the control of neuronal excitability by homeostatic mechanisms. The AIS has high plasticity in normal developmental processes and pathological activities, such as injury, neurodegeneration, and neurodevelopmental disorders (NDDs). In the first half of this review, we provide an overview of the molecular, structural, and ion-channel characteristics of AIS, AIS regulation through axo-axonic synapses, and axo-glial interactions. In the second half, to understand the relationship between NDDs and AIS, we discuss the activity-dependent plasticity of AIS, the human mutation of AIS regulatory genes, and the pathophysiological role of an abnormal AIS in NDD model animals and patients. We propose that the AIS may provide a potentially valuable structural biomarker in response to abnormal network activity in vivo as well as a new treatment concept at the neural circuit level.
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Affiliation(s)
- Masashi Fujitani
- Department of Anatomy and Neuroscience, Faculty of Medicine, Shimane University, 89-1 Enya-cho, Izumo-shi 693-8501, Shimane, Japan; (Y.O.); (H.M.)
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15
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Cousin MA, Creighton BA, Breau KA, Spillmann RC, Torti E, Dontu S, Tripathi S, Ajit D, Edwards RJ, Afriyie S, Bay JC, Harper KM, Beltran AA, Munoz LJ, Falcon Rodriguez L, Stankewich MC, Person RE, Si Y, Normand EA, Blevins A, May AS, Bier L, Aggarwal V, Mancini GMS, van Slegtenhorst MA, Cremer K, Becker J, Engels H, Aretz S, MacKenzie JJ, Brilstra E, van Gassen KLI, van Jaarsveld RH, Oegema R, Parsons GM, Mark P, Helbig I, McKeown SE, Stratton R, Cogne B, Isidor B, Cacheiro P, Smedley D, Firth HV, Bierhals T, Kloth K, Weiss D, Fairley C, Shieh JT, Kritzer A, Jayakar P, Kurtz-Nelson E, Bernier RA, Wang T, Eichler EE, van de Laar IMBH, McConkie-Rosell A, McDonald MT, Kemppainen J, Lanpher BC, Schultz-Rogers LE, Gunderson LB, Pichurin PN, Yoon G, Zech M, Jech R, Winkelmann J, Beltran AS, Zimmermann MT, Temple B, Moy SS, Klee EW, Tan QKG, Lorenzo DN. Pathogenic SPTBN1 variants cause an autosomal dominant neurodevelopmental syndrome. Nat Genet 2021; 53:1006-1021. [PMID: 34211179 PMCID: PMC8273149 DOI: 10.1038/s41588-021-00886-z] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 05/14/2021] [Indexed: 12/22/2022]
Abstract
SPTBN1 encodes βII-spectrin, the ubiquitously expressed β-spectrin that forms micrometer-scale networks associated with plasma membranes. Mice deficient in neuronal βII-spectrin have defects in cortical organization, developmental delay and behavioral deficiencies. These phenotypes, while less severe, are observed in haploinsufficient animals, suggesting that individuals carrying heterozygous SPTBN1 variants may also show measurable compromise of neural development and function. Here we identify heterozygous SPTBN1 variants in 29 individuals with developmental, language and motor delays; mild to severe intellectual disability; autistic features; seizures; behavioral and movement abnormalities; hypotonia; and variable dysmorphic facial features. We show that these SPTBN1 variants lead to effects that affect βII-spectrin stability, disrupt binding to key molecular partners, and disturb cytoskeleton organization and dynamics. Our studies define SPTBN1 variants as the genetic basis of a neurodevelopmental syndrome, expand the set of spectrinopathies affecting the brain and underscore the critical role of βII-spectrin in the central nervous system.
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Affiliation(s)
- Margot A Cousin
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA.
- Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN, USA.
| | - Blake A Creighton
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Keith A Breau
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Rebecca C Spillmann
- Department of Pediatrics, Duke University Medical Center, Duke University, Durham, NC, USA
| | | | - Sruthi Dontu
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Swarnendu Tripathi
- Bioinformatics Research and Development Laboratory, Genomic Sciences and Precision Medicine Center, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Deepa Ajit
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Reginald J Edwards
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Simone Afriyie
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Julia C Bay
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Kathryn M Harper
- Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Carolina Institute for Developmental Disabilities, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Alvaro A Beltran
- Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Human Pluripotent Stem Cell Core, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Lorena J Munoz
- Human Pluripotent Stem Cell Core, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Liset Falcon Rodriguez
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | | | | | - Yue Si
- GeneDx, Gaithersburg, MD, USA
| | | | | | - Alison S May
- Department of Neurology, Columbia University, New York, NY, USA
| | - Louise Bier
- Institute for Genomic Medicine, Columbia University, New York, NY, USA
| | - Vimla Aggarwal
- Institute for Genomic Medicine, Columbia University, New York, NY, USA
- Laboratory of Personalized Genomic Medicine, Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
| | - Grazia M S Mancini
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, the Netherlands
| | | | - Kirsten Cremer
- Institute of Human Genetics, University of Bonn, School of Medicine & University Hospital Bonn, Bonn, Germany
| | - Jessica Becker
- Institute of Human Genetics, University of Bonn, School of Medicine & University Hospital Bonn, Bonn, Germany
| | - Hartmut Engels
- Institute of Human Genetics, University of Bonn, School of Medicine & University Hospital Bonn, Bonn, Germany
| | - Stefan Aretz
- Institute of Human Genetics, University of Bonn, School of Medicine & University Hospital Bonn, Bonn, Germany
| | | | - Eva Brilstra
- Department of Genetics, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Koen L I van Gassen
- Department of Genetics, University Medical Center Utrecht, Utrecht, the Netherlands
| | | | - Renske Oegema
- Department of Genetics, University Medical Center Utrecht, Utrecht, the Netherlands
| | | | - Paul Mark
- Spectrum Health Medical Genetics, Grand Rapids, MI, USA
| | - Ingo Helbig
- Division of Neurology, Departments of Neurology and Pediatrics, The Children's Hospital of Philadelphia and the Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
- The Epilepsy NeuroGenetics Initiative, Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Biomedical and Health Informatics (DBHi), Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Neurology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
| | - Sarah E McKeown
- Division of Neurology, Departments of Neurology and Pediatrics, The Children's Hospital of Philadelphia and the Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
- The Epilepsy NeuroGenetics Initiative, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Robert Stratton
- Genetics, Driscoll Children's Hospital, Corpus Christi, TX, USA
| | - Benjamin Cogne
- Service de Génétique Médicale, CHU Nantes, Nantes, France
- Université de Nantes, CNRS, INSERM, L'Institut du Thorax, Nantes, France
| | - Bertrand Isidor
- Service de Génétique Médicale, CHU Nantes, Nantes, France
- Université de Nantes, CNRS, INSERM, L'Institut du Thorax, Nantes, France
| | - Pilar Cacheiro
- William Harvey Research Institute, School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Damian Smedley
- William Harvey Research Institute, School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Helen V Firth
- Department of Clinical Genetics, Cambridge University Hospitals, Cambridge, UK
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, UK
| | - Tatjana Bierhals
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Katja Kloth
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Deike Weiss
- Neuropediatrics, Department of Pediatrics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Cecilia Fairley
- Division of Medical Genetics, Department of Pediatrics, University of California San Francisco, San Francisco, CA, USA
| | - Joseph T Shieh
- Division of Medical Genetics, Department of Pediatrics, University of California San Francisco, San Francisco, CA, USA
- Institute for Human Genetics, University of California San Francisco, San Francisco, CA, USA
| | - Amy Kritzer
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, USA
| | | | - Evangeline Kurtz-Nelson
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, USA
| | - Raphael A Bernier
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, USA
| | - Tianyun Wang
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA, USA
| | - Evan E Eichler
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA, USA
- Howard Hughes Medical Institute, University of Washington, Seattle, WA, USA
| | - Ingrid M B H van de Laar
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, the Netherlands
| | - Allyn McConkie-Rosell
- Department of Pediatrics, Duke University Medical Center, Duke University, Durham, NC, USA
| | - Marie T McDonald
- Department of Pediatrics, Duke University Medical Center, Duke University, Durham, NC, USA
| | - Jennifer Kemppainen
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN, USA
| | - Brendan C Lanpher
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN, USA
| | - Laura E Schultz-Rogers
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA
- Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN, USA
| | - Lauren B Gunderson
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN, USA
| | - Pavel N Pichurin
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA
| | - Grace Yoon
- Divisions of Clinical/Metabolic Genetics and Neurology, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Michael Zech
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany
- Institute of Human Genetics, Technical University of Munich, Munich, Germany
| | - Robert Jech
- Department of Neurology, Charles University, 1st Faculty of Medicine and General University Hospital in Prague, Prague, Czech Republic
| | - Juliane Winkelmann
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany
- Institute of Human Genetics, Technical University of Munich, Munich, Germany
- Lehrstuhl für Neurogenetik, Technische Universität München, Munich, Germany
- Munich Cluster for Systems Neurology, SyNergy, Munich, Germany
| | - Adriana S Beltran
- Human Pluripotent Stem Cell Core, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Michael T Zimmermann
- Bioinformatics Research and Development Laboratory, Genomic Sciences and Precision Medicine Center, Medical College of Wisconsin, Milwaukee, WI, USA
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI, USA
- Clinical and Translational Sciences Institute, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Brenda Temple
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Sheryl S Moy
- Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Carolina Institute for Developmental Disabilities, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Eric W Klee
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA
- Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN, USA
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN, USA
| | - Queenie K-G Tan
- Department of Pediatrics, Duke University Medical Center, Duke University, Durham, NC, USA
| | - Damaris N Lorenzo
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Carolina Institute for Developmental Disabilities, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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16
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Rosenfeld JA, Xiao R, Bekheirnia MR, Kanani F, Parker MJ, Koenig MK, van Haeringen A, Ruivenkamp C, Rosmaninho-Salgado J, Almeida PM, Sá J, Basto JP, Palen E, Oetjens KF, Burrage LC, Xia F, Liu P, Eng CM, Yang Y, Posey JE, Lee BH. Heterozygous variants in SPTBN1 cause intellectual disability and autism. Am J Med Genet A 2021; 185:2037-2045. [PMID: 33847457 PMCID: PMC11182376 DOI: 10.1002/ajmg.a.62201] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Revised: 02/26/2021] [Accepted: 03/24/2021] [Indexed: 11/09/2022]
Abstract
Spectrins are common components of cytoskeletons, binding to cytoskeletal elements and the plasma membrane, allowing proper localization of essential membrane proteins, signal transduction, and cellular scaffolding. Spectrins are assembled from α and β subunits, encoded by SPTA1 and SPTAN1 (α) and SPTB, SPTBN1, SPTBN2, SPTBN4, and SPTBN5 (β). Pathogenic variants in various spectrin genes are associated with erythroid cell disorders (SPTA1, SPTB) and neurologic disorders (SPTAN1, SPTBN2, and SPTBN4), but no phenotypes have been definitively associated with variants in SPTBN1 or SPTBN5. Through exome sequencing and case matching, we identified seven unrelated individuals with heterozygous SPTBN1 variants: two with de novo missense variants and five with predicted loss-of-function variants (found to be de novo in two, while one was inherited from a mother with a history of learning disabilities). Common features include global developmental delays, intellectual disability, and behavioral disturbances. Autistic features (4/6) and epilepsy (2/7) or abnormal electroencephalogram without overt seizures (1/7) were present in a subset. Identification of loss-of-function variants suggests a haploinsufficiency mechanism, but additional functional studies are required to fully elucidate disease pathogenesis. Our findings support the essential roles of SPTBN1 in human neurodevelopment and expand the knowledge of human spectrinopathy disorders.
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Affiliation(s)
- Jill A. Rosenfeld
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Rui Xiao
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
- Baylor Genetics Laboratories, Houston, Texas, 77030, USA
| | - Mir Reza Bekheirnia
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
- Renal Section, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Farah Kanani
- Sheffield Clinical Genetics Service, Sheffield Children's NHS Foundation Trust, Sheffield, UK
| | - Michael J. Parker
- The Wellcome Centre for Ethics and Humanities/Ethox Centre, Nuffield Department of Population Health, University of Oxford, Oxford, UK
| | - Mary K. Koenig
- Department of Pediatrics, University of Texas Health Science Center, Houston, Texas, 77030, USA
| | - Arie van Haeringen
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, Netherlands
| | - Claudia Ruivenkamp
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, Netherlands
| | - Joana Rosmaninho-Salgado
- Medical Genetics Unit, Hospital Pediátrico, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal
| | - Pedro M. Almeida
- Medical Genetics Unit, Hospital Pediátrico, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal
| | - Joaquim Sá
- Medical Genetics Unit, Hospital Pediátrico, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal
| | - Jorge Pinto Basto
- Molecular Diagnostics and Clinical Genomics, CGC Genetics, Porto, Portugal
| | - Emily Palen
- Autism & Developmental Medicine Institute, Geisinger, Danville, Pennsylvania, 17822, USA
| | - Kathryn F. Oetjens
- Autism & Developmental Medicine Institute, Geisinger, Danville, Pennsylvania, 17822, USA
| | - Lindsay C. Burrage
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
- Texas Children’s Hospital, Houston, Texas, 77030, USA
| | - Fan Xia
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
- Baylor Genetics Laboratories, Houston, Texas, 77030, USA
| | - Pengfei Liu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
- Baylor Genetics Laboratories, Houston, Texas, 77030, USA
| | - Christine M. Eng
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
- Baylor Genetics Laboratories, Houston, Texas, 77030, USA
| | | | - Yaping Yang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
- Baylor Genetics Laboratories, Houston, Texas, 77030, USA
| | - Jennifer E. Posey
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Brendan H. Lee
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
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17
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Regulation of Cardiac Conduction and Arrhythmias by Ankyrin/Spectrin-Based Macromolecular Complexes. J Cardiovasc Dev Dis 2021; 8:jcdd8050048. [PMID: 33946725 PMCID: PMC8146975 DOI: 10.3390/jcdd8050048] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 04/15/2021] [Accepted: 04/19/2021] [Indexed: 12/19/2022] Open
Abstract
The cardiac conduction system is an extended network of excitable tissue tasked with generation and propagation of electrical impulses to signal coordinated contraction of the heart. The fidelity of this system depends on the proper spatio-temporal regulation of ion channels in myocytes throughout the conduction system. Importantly, inherited or acquired defects in a wide class of ion channels has been linked to dysfunction at various stages of the conduction system resulting in life-threatening cardiac arrhythmia. There is growing appreciation of the role that adapter and cytoskeletal proteins play in organizing ion channel macromolecular complexes critical for proper function of the cardiac conduction system. In particular, members of the ankyrin and spectrin families have emerged as important nodes for normal expression and regulation of ion channels in myocytes throughout the conduction system. Human variants impacting ankyrin/spectrin function give rise to a broad constellation of cardiac arrhythmias. Furthermore, chronic neurohumoral and biomechanical stress promotes ankyrin/spectrin loss of function that likely contributes to conduction disturbances in the setting of acquired cardiac disease. Collectively, this review seeks to bring attention to the significance of these cytoskeletal players and emphasize the potential therapeutic role they represent in a myriad of cardiac disease states.
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18
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Belkheir AM, Reunert J, Elpers C, van den Heuvel L, Rodenburg R, Seelhöfer A, Rust S, Jeibmann A, Frosch M, Marquardt T. Severe Form of ßIV-Spectrin Deficiency With Mitochondrial Dysfunction and Cardiomyopathy-A Case Report. Front Neurol 2021; 12:643805. [PMID: 33986717 PMCID: PMC8110827 DOI: 10.3389/fneur.2021.643805] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 03/25/2021] [Indexed: 11/13/2022] Open
Abstract
ßIV-spectrin is a protein of the spectrin family which is involved in the organization of the cytoskeleton structure and is found in high quantity in the axon initial segment and the nodes of Ranvier. Together with ankyrin G, ßIV-spectrin is responsible for the clustering of KCNQ2/3-potassium channels and NaV-sodium channels. Loss or reduction of ßIV-spectrin causes a destabilization of the cytoskeleton and an impairment in the generation of the action potential, which leads to neuronal degeneration. Furthermore, ßIV-spectrin has been described to play an important role in the maintenance of the neuronal polarity and of the diffusion barrier. ßIV-spectrin is also located in the heart where it takes an important part in the structural organization of ion channels and has also been described to participate in cell signaling pathways through binding of transcription factors. We describe two patients with a severe form of ßIV-spectrin deficiency. Whole-exome sequencing revealed the homozygous stop mutation c.6016C>T (p.R2006*) in the SPTBN4 gene. The phenotype of these patients is characterized by profound psychomotor developmental arrest, respiratory insufficiency and deafness. Additionally one of the patients presents with cardiomyopathy, optical nerve atrophy, and mitochondrial dysfunction. This is the first report of a severe form of ßIV-spectrin deficiency with hypertrophic cardiomyopathy and mitochondrial dysfunction.
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Affiliation(s)
- Aziza Miriam Belkheir
- Department of General Paediatrics, Metabolic Diseases, University Children's Hospital Muenster, Münster, Germany
| | - Janine Reunert
- Department of General Paediatrics, Metabolic Diseases, University Children's Hospital Muenster, Münster, Germany
| | - Christiane Elpers
- Department of General Paediatrics, Metabolic Diseases, University Children's Hospital Muenster, Münster, Germany
| | - Lambert van den Heuvel
- Translational Metabolic Laboratory, Department of Paediatrics, Radboud Center for Mitochondrial Medicine, Radboud UMC, Nijmegen, Netherlands
| | - Richard Rodenburg
- Translational Metabolic Laboratory, Department of Paediatrics, Radboud Center for Mitochondrial Medicine, Radboud UMC, Nijmegen, Netherlands
| | - Anja Seelhöfer
- Department of General Paediatrics, Metabolic Diseases, University Children's Hospital Muenster, Münster, Germany
| | - Stephan Rust
- Department of General Paediatrics, Metabolic Diseases, University Children's Hospital Muenster, Münster, Germany
| | - Astrid Jeibmann
- Institute of Neuropathology, University Hospital Muenster, Münster, Germany
| | - Michael Frosch
- Department of Children's Pain Therapy and Paediatric Palliative Care, Faculty of Health-School of Medicine, Witten/Herdecke University, Witten, Germany
| | - Thorsten Marquardt
- Department of General Paediatrics, Metabolic Diseases, University Children's Hospital Muenster, Münster, Germany
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19
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Buelow M, Süßmuth D, Smith LD, Aryani O, Castiglioni C, Stenzel W, Bertini E, Schuelke M, Knierim E. Novel bi-allelic variants expand the SPTBN4-related genetic and phenotypic spectrum. Eur J Hum Genet 2021; 29:1121-1128. [PMID: 33772159 PMCID: PMC8298470 DOI: 10.1038/s41431-021-00846-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 02/04/2021] [Accepted: 02/25/2021] [Indexed: 11/09/2022] Open
Abstract
Neurodevelopmental disorder with hypotonia, neuropathy, and deafness (NEDHND, OMIM #617519) is an autosomal recessive disease caused by homozygous or compound heterozygous variants in SPTBN4 coding for type 4 βIV-spectrin, a non-erythrocytic member of the β-spectrin family. Variants in SPTBN4 disrupt the cytoskeletal machinery that controls proper localization of ion channels and the function of axonal domains, thereby generating severe neurological dysfunction. We set out to analyze the genetic causes and describe the clinical spectrum of suspected cases of NEDHND. Variant screening was done by whole exome sequencing; clinical phenotypes were described according to the human phenotype ontology, and histochemical analysis was performed with disease-specific antibodies. We report four families with five patients harboring novel homozygous and compound heterozygous SPTBN4 variants, amongst them a multi-exon deletion of SPTBN4. All patients presented with the key features of NEDHND; severe muscular hypotonia, dysphagia, absent speech, gross motor, and mental retardation. Additional symptoms comprised horizontal nystagmus, epileptiform discharges in EEG without manifest seizures, and choreoathetosis. Muscle histology revealed both characteristics of myopathy and of neuropathy. This report expands the SPTBN4 variant spectrum, highlights the spectrum of morphological phenotypes of NEDHND-patients, and reveals clinical similarities between the NEDHND, non-5q SMA, and congenital myopathies.
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Affiliation(s)
- Markus Buelow
- Department of Neuropediatrics, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin und Humboldt Universität zu Berlin, Berlin, Germany
| | - David Süßmuth
- HELIOS Kliniken - Helios Klinikum Hohenstücken, Berlin, Germany
| | - Laurie D Smith
- Department of Pediatrics, Division of Pediatric Genetics and Metabolism, The University of North Carolina SOM, North Carolina, NC, USA
| | - Omid Aryani
- Department of Neuroscience, Iranian University of Medical Sciences, Tehran, Iran
| | | | - Werner Stenzel
- Department of Neuropathology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin und Humboldt Universität zu Berlin, Berlin, Germany
| | - Enrico Bertini
- Unit of Neuromuscular and Neurodegenerative Disorders, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy
| | - Markus Schuelke
- Department of Neuropediatrics, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin und Humboldt Universität zu Berlin, Berlin, Germany.,NeuroCure Clinical Research Center, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin und Humboldt Universität zu Berlin, Berlin, Germany
| | - Ellen Knierim
- Department of Neuropediatrics, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin und Humboldt Universität zu Berlin, Berlin, Germany. .,NeuroCure Clinical Research Center, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin und Humboldt Universität zu Berlin, Berlin, Germany.
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20
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Van de Vondel L, Baets J, Beijer D. Reply: De novo SPTAN1 mutation in axonal sensorimotor neuropathy and developmental disorder. Brain 2021; 143:e105. [PMID: 33207363 DOI: 10.1093/brain/awaa345] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Liedewei Van de Vondel
- Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Belgium.,Laboratory of Neuromuscular Pathology, Institute Born-Bunge, University of Antwerp, Belgium
| | - Jonathan Baets
- Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Belgium.,Laboratory of Neuromuscular Pathology, Institute Born-Bunge, University of Antwerp, Belgium.,Neuromuscular Reference Centre, Department of Neurology, Antwerp University Hospital, Belgium
| | - Danique Beijer
- Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Belgium.,Laboratory of Neuromuscular Pathology, Institute Born-Bunge, University of Antwerp, Belgium
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21
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Gao H, Tripathi U, Trushin S, Okromelidze L, Pichurin NP, Wei L, Zhuang Y, Wang L, Trushina E. A genome-wide association study in human lymphoblastoid cells supports safety of mitochondrial complex I inhibitor. Mitochondrion 2021; 58:83-94. [PMID: 33610756 DOI: 10.1016/j.mito.2021.02.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 02/08/2021] [Indexed: 01/12/2023]
Abstract
Novel therapeutic strategies for Alzheimer's disease (AD) are of the greatest priority given the consistent failure of recent clinical trials focused on Aβ or pTau. Earlier, we demonstrated that mild mitochondrial complex I inhibitor CP2 blocks neurodegeneration and cognitive decline in multiple mouse models of AD. To evaluate the safety of CP2 in humans, we performed a genome-wide association study (GWAS) using 196 lymphoblastoid cell lines and identified 11 SNP loci and 64 mRNA expression probe sets that potentially associate with CP2 susceptibility. Using primary mouse neurons and pharmacokinetic study, we show that CP2 is generally safe at a therapeutic dose.
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Affiliation(s)
- Huanyao Gao
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, 200 First St. SW, Rochester, MN, 55905, USA
| | - Utkarsh Tripathi
- Department of Neurology, Mayo Clinic, 200 First St. SW, Rochester, MN, 55905, USA
| | - Sergey Trushin
- Department of Neurology, Mayo Clinic, 200 First St. SW, Rochester, MN, 55905, USA
| | - Lela Okromelidze
- Department of Neurology, Mayo Clinic, 200 First St. SW, Rochester, MN, 55905, USA
| | - Nicholas P Pichurin
- Department of Neurology, Mayo Clinic, 200 First St. SW, Rochester, MN, 55905, USA
| | - Lixuan Wei
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, 200 First St. SW, Rochester, MN, 55905, USA
| | - Yongxian Zhuang
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, 200 First St. SW, Rochester, MN, 55905, USA
| | - Liewei Wang
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, 200 First St. SW, Rochester, MN, 55905, USA
| | - Eugenia Trushina
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, 200 First St. SW, Rochester, MN, 55905, USA; Department of Neurology, Mayo Clinic, 200 First St. SW, Rochester, MN, 55905, USA.
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22
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Abstract
The nodes of Ranvier have clustered Na+ and K+ channels necessary for rapid and efficient axonal action potential conduction. However, detailed mechanisms of channel clustering have only recently been identified: they include two independent axon-glia interactions that converge on distinct axonal cytoskeletons. Here, we discuss how glial cell adhesion molecules and the extracellular matrix molecules that bind them assemble combinations of ankyrins, spectrins and other cytoskeletal scaffolding proteins, which cluster ion channels. We present a detailed molecular model, incorporating these overlapping mechanisms, to explain how the nodes of Ranvier are assembled in both the peripheral and central nervous systems.
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23
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Li J, Chen K, Zhu R, Zhang M. Structural Basis Underlying Strong Interactions between Ankyrins and Spectrins. J Mol Biol 2020; 432:3838-3850. [DOI: 10.1016/j.jmb.2020.04.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Revised: 04/18/2020] [Accepted: 04/23/2020] [Indexed: 01/06/2023]
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24
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Liu CH, Seo R, Ho TSY, Stankewich M, Mohler PJ, Hund TJ, Noebels JL, Rasband MN. β spectrin-dependent and domain specific mechanisms for Na + channel clustering. eLife 2020; 9:e56629. [PMID: 32425157 PMCID: PMC7237202 DOI: 10.7554/elife.56629] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 05/07/2020] [Indexed: 12/23/2022] Open
Abstract
Previously, we showed that a hierarchy of spectrin cytoskeletal proteins maintains nodal Na+ channels (Liu et al., 2020). Here, using mice lacking β1, β4, or β1/β4 spectrins, we show this hierarchy does not function at axon initial segments (AIS). Although β1 spectrin, together with AnkyrinR (AnkR), compensates for loss of nodal β4 spectrin, it cannot compensate at AIS. We show AnkR lacks the domain necessary for AIS localization. Whereas loss of β4 spectrin causes motor impairment and disrupts AIS, loss of β1 spectrin has no discernable effect on central nervous system structure or function. However, mice lacking both neuronal β1 and β4 spectrin show exacerbated nervous system dysfunction compared to mice lacking β1 or β4 spectrin alone, including profound disruption of AIS Na+ channel clustering, progressive loss of nodal Na+ channels, and seizures. These results further define the important role of AIS and nodal spectrins for nervous system function.
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Affiliation(s)
- Cheng-Hsin Liu
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
- Program in Developmental Biology, Baylor College of MedicineHoustonUnited States
| | - Ryan Seo
- Department of Neurology, Baylor College of MedicineHoustonUnited States
| | - Tammy Szu-Yu Ho
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
| | | | - Peter J Mohler
- Department of Physiology and Cell Biology, The Ohio State UniversityColumbusUnited States
| | - Thomas J Hund
- Department of Biomedical Engineering, The Ohio State UniversityColumbusUnited States
| | - Jeffrey L Noebels
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
- Department of Neurology, Baylor College of MedicineHoustonUnited States
| | - Matthew N Rasband
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
- Program in Developmental Biology, Baylor College of MedicineHoustonUnited States
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25
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Häusler MG, Begemann M, Lidov HG, Kurth I, Darras BT, Elbracht M. A novel homozygous splice-site mutation in the SPTBN4 gene causes axonal neuropathy without intellectual disability. Eur J Med Genet 2019; 63:103826. [PMID: 31857255 DOI: 10.1016/j.ejmg.2019.103826] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 11/14/2019] [Accepted: 12/14/2019] [Indexed: 10/25/2022]
Abstract
Mutations in spectrin beta non-erythrocytic 4 (SPTBN4) have been linked to congenital hypotonia, intellectual disability and motor neuropathy. Here we report on two siblings with a homozygous splice-site mutation in the SPTBN4 gene, lacking previously reported features of the disorder such as seizures, feeding difficulties, respiratory difficulties or profound intellectual disability. Our findings indicate that muscular hypotonia, myopathic facies with ptosis and axonal neuropathy can be the core clinical features in the SPTBN4 disorder and suggest that SPTBN4 mutation analysis should be considered in infants with marked axonal neuropathy.
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Affiliation(s)
- Martin G Häusler
- Division of Neuropediatrics and Social Pediatrics, Medical Faculty, RWTH Aachen University, Aachen, Germany.
| | - Matthias Begemann
- Institute of Human Genetics, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Hart G Lidov
- Department of Pathology, Boston Children's Hospital and Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Ingo Kurth
- Institute of Human Genetics, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Basil T Darras
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Miriam Elbracht
- Institute of Human Genetics, Medical Faculty, RWTH Aachen University, Aachen, Germany
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26
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Radke J, Stenzel W, Goebel HH. Corrigendum to "Recently Identified Congenital Myopathies" [Semin Pediatr Neurol 29 (2019) 83-90]. Semin Pediatr Neurol 2019; 32:100775. [PMID: 31813515 DOI: 10.1016/j.spen.2019.100775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Josefine Radke
- Department of Neuropathology, Charite - Universitätsmedizin Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.
| | - Werner Stenzel
- Department of Neuropathology, Charite - Universitätsmedizin Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Hans H Goebel
- Department of Neuropathology, Charite - Universitätsmedizin Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
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27
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Derks MFL, Harlizius B, Lopes MS, Greijdanus-van der Putten SWM, Dibbits B, Laport K, Megens HJ, Groenen MAM. Detection of a Frameshift Deletion in the SPTBN4 Gene Leads to Prevention of Severe Myopathy and Postnatal Mortality in Pigs. Front Genet 2019; 10:1226. [PMID: 31850074 PMCID: PMC6902008 DOI: 10.3389/fgene.2019.01226] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 11/05/2019] [Indexed: 11/26/2022] Open
Abstract
Piglet mortality is a complex phenotype that depends on the environment, selection on piglet health, but also on the interaction between the piglet and sow. However, also monogenic recessive defects contribute to piglet mortality. Selective breeding has decreased overall piglet mortality by improving both mothering abilities and piglet viability. However, variants underlying recessive monogenic defects are usually not well captured within the breeding values, potentially drifting to higher frequency as a result of intense selection or genetic drift. This study describes the identification by whole-genome sequencing of a recessive 16-bp deletion in the SPTBN4 gene causing postnatal mortality in a pig breeding line. The deletion induces a frameshift and a premature stop codon, producing an impaired and truncated spectrin beta non-erythrocytic 4 protein (SPTBN4). Applying medium density single nucleotide polymorphism (SNP) data available for all breeding animals, a pregnant carrier sow sired by a carrier boar was identified. Of the resulting piglets, two confirmed homozygous piglets suffered from severe myopathy, hind-limb paralysis, and tremors. Histopathological examination showed dispersed degeneration and decrease of cross-striations in the dorsal and hind-limb muscle fibers of the affected piglets. Hence, the affected piglets are unable to walk or drink, usually resulting in death within a few hours after birth. This study demonstrates how growing genomic resources in pig breeding can be applied to identify rare syndromes in breeding populations, that are usually poorly documented and often are not even known to have a genetic basis. The study allows to prevent carrier-by-carrier matings, thereby gradually decreasing the frequency of the detrimental allele and avoiding the birth of affected piglets, improving animal welfare. Finally, these "natural knockouts" increase our understanding of gene function within the mammalian clade, and provide a potential model for human disease.
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Affiliation(s)
- Martijn F. L. Derks
- Animal Breeding and Genomics, Wageningen University & Research, Wageningen, Netherlands
| | | | - Marcos S. Lopes
- Topigs Norsvin Research Center, Beuningen, Netherlands
- Topigs Norsvin, Curitiba, Brazil
| | | | - Bert Dibbits
- Animal Breeding and Genomics, Wageningen University & Research, Wageningen, Netherlands
| | - Kimberley Laport
- Animal Breeding and Genomics, Wageningen University & Research, Wageningen, Netherlands
| | - Hendrik-Jan Megens
- Animal Breeding and Genomics, Wageningen University & Research, Wageningen, Netherlands
| | - Martien A. M. Groenen
- Animal Breeding and Genomics, Wageningen University & Research, Wageningen, Netherlands
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28
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Patel NJ, Nassal DM, Greer-Short AD, Unudurthi SD, Scandling BW, Gratz D, Xu X, Kalyanasundaram A, Fedorov VV, Accornero F, Mohler PJ, Gooch KJ, Hund TJ. βIV-Spectrin/STAT3 complex regulates fibroblast phenotype, fibrosis, and cardiac function. JCI Insight 2019; 4:131046. [PMID: 31550236 DOI: 10.1172/jci.insight.131046] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 09/18/2019] [Indexed: 01/30/2023] Open
Abstract
Increased fibrosis is a characteristic remodeling response to biomechanical and neurohumoral stress and a determinant of cardiac mechanical and electrical dysfunction in disease. Stress-induced activation of cardiac fibroblasts (CFs) is a critical step in the fibrotic response, although the precise sequence of events underlying activation of these critical cells in vivo remain unclear. Here, we tested the hypothesis that a βIV-spectrin/STAT3 complex is essential for maintenance of a quiescent phenotype (basal nonactivated state) in CFs. We reported increased fibrosis, decreased cardiac function, and electrical impulse conduction defects in genetic and acquired mouse models of βIV-spectrin deficiency. Loss of βIV-spectrin function promoted STAT3 nuclear accumulation and transcriptional activity, and it altered gene expression and CF activation. Furthermore, we demonstrate that a quiescent phenotype may be restored in βIV-spectrin-deficient fibroblasts by expressing a βIV-spectrin fragment including the STAT3-binding domain or through pharmacological STAT3 inhibition. We found that in vivo STAT3 inhibition abrogates fibrosis and cardiac dysfunction in the setting of global βIV-spectrin deficiency. Finally, we demonstrate that fibroblast-specific deletion of βIV-spectrin is sufficient to induce fibrosis and decreased cardiac function. We propose that the βIV-spectrin/STAT3 complex is a determinant of fibroblast phenotype and fibrosis, with implications for remodeling response in cardiovascular disease (CVD).
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Affiliation(s)
- Nehal J Patel
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Drew M Nassal
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Amara D Greer-Short
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Sathya D Unudurthi
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Benjamin W Scandling
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Daniel Gratz
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Xianyao Xu
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Anuradha Kalyanasundaram
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Physiology and Cell Biology, and
| | - Vadim V Fedorov
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Physiology and Cell Biology, and
| | - Federica Accornero
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Physiology and Cell Biology, and
| | - Peter J Mohler
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Physiology and Cell Biology, and.,Department of Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Keith J Gooch
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Thomas J Hund
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA.,Department of Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
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29
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Pehlivan D, Bayram Y, Gunes N, Coban Akdemir Z, Shukla A, Bierhals T, Tabakci B, Sahin Y, Gezdirici A, Fatih JM, Gulec EY, Yesil G, Punetha J, Ocak Z, Grochowski CM, Karaca E, Albayrak HM, Radhakrishnan P, Erdem HB, Sahin I, Yildirim T, Bayhan IA, Bursali A, Elmas M, Yuksel Z, Ozdemir O, Silan F, Yildiz O, Yesilbas O, Isikay S, Balta B, Gu S, Jhangiani SN, Doddapaneni H, Hu J, Muzny DM, Boerwinkle E, Gibbs RA, Tsiakas K, Hempel M, Girisha KM, Gul D, Posey JE, Elcioglu NH, Tuysuz B, Lupski JR. The Genomics of Arthrogryposis, a Complex Trait: Candidate Genes and Further Evidence for Oligogenic Inheritance. Am J Hum Genet 2019; 105:132-150. [PMID: 31230720 PMCID: PMC6612529 DOI: 10.1016/j.ajhg.2019.05.015] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 05/21/2019] [Indexed: 01/29/2023] Open
Abstract
Arthrogryposis is a clinical finding that is present either as a feature of a neuromuscular condition or as part of a systemic disease in over 400 Mendelian conditions. The underlying molecular etiology remains largely unknown because of genetic and phenotypic heterogeneity. We applied exome sequencing (ES) in a cohort of 89 families with the clinical sign of arthrogryposis. Additional molecular techniques including array comparative genomic hybridization (aCGH) and Droplet Digital PCR (ddPCR) were performed on individuals who were found to have pathogenic copy number variants (CNVs) and mosaicism, respectively. A molecular diagnosis was established in 65.2% (58/89) of families. Eleven out of 58 families (19.0%) showed evidence for potential involvement of pathogenic variation at more than one locus, probably driven by absence of heterozygosity (AOH) burden due to identity-by-descent (IBD). RYR3, MYOM2, ERGIC1, SPTBN4, and ABCA7 represent genes, identified in two or more families, for which mutations are probably causative for arthrogryposis. We also provide evidence for the involvement of CNVs in the etiology of arthrogryposis and for the idea that both mono-allelic and bi-allelic variants in the same gene cause either similar or distinct syndromes. We were able to identify the molecular etiology in nine out of 20 families who underwent reanalysis. In summary, our data from family-based ES further delineate the molecular etiology of arthrogryposis, yielded several candidate disease-associated genes, and provide evidence for mutational burden in a biological pathway or network. Our study also highlights the importance of reanalysis of individuals with unsolved diagnoses in conjunction with sequencing extended family members.
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Affiliation(s)
- Davut Pehlivan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Section of Pediatric Neurology and Developmental Neuroscience, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Yavuz Bayram
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Nilay Gunes
- Department of Pediatric Genetics, Istanbul University-Cerrahpasa Medical Faculty, Istanbul 34096, Turkey
| | - Zeynep Coban Akdemir
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Anju Shukla
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal 576104, India
| | - Tatjana Bierhals
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Martinistraße 52, Hamburg 20246, Germany
| | - Burcu Tabakci
- Department of Pediatric Genetics, Marmara University Medical School, Istanbul 34854, Turkey
| | - Yavuz Sahin
- Department of Medical Genetics, Necip Fazıl City Hospital, Kahramanmaras 46050, Turkey
| | - Alper Gezdirici
- Department of Medical Genetics, Kanuni Sultan Suleyman Training and Research Hospital, Istanbul 34303, Turkey
| | - Jawid M Fatih
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Elif Yilmaz Gulec
- Department of Medical Genetics, Kanuni Sultan Suleyman Training and Research Hospital, Istanbul 34303, Turkey
| | - Gozde Yesil
- Department of Medical Genetics, Bezmi Alem Vakif University Faculty of Medicine, Istanbul 34093, Turkey
| | - Jaya Punetha
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Zeynep Ocak
- Department of Medical Genetics, Kanuni Sultan Suleyman Training and Research Hospital, Istanbul 34303, Turkey
| | | | - Ender Karaca
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Hatice Mutlu Albayrak
- Department of Pediatrics, Division of Pediatric Genetics, Faculty of Medicine, Ondokuz Mayıs University, Samsun 55270, Turkey
| | - Periyasamy Radhakrishnan
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal 576104, India
| | - Haktan Bagis Erdem
- Department of Medical Genetics, University of Health Sciences, Diskapi Yildirim Beyazit Training and Research Hospital, Ankara 06110, Turkey
| | - Ibrahim Sahin
- Department of Medical Genetics, University of Erzurum, School of Medicine, Erzurum 25240, Turkey
| | - Timur Yildirim
- Department of Orthopedics and Traumatology, Baltalimani Bone Diseases Training and Research Hospital, Istanbul 34470, Turkey
| | - Ilhan A Bayhan
- Department of Orthopedics and Traumatology, Baltalimani Bone Diseases Training and Research Hospital, Istanbul 34470, Turkey
| | - Aysegul Bursali
- Department of Orthopedics and Traumatology, Baltalimani Bone Diseases Training and Research Hospital, Istanbul 34470, Turkey
| | - Muhsin Elmas
- Department of Medical Genetics, Afyon Kocatepe University, School of Medicine, Afyon 03218, Turkey
| | - Zafer Yuksel
- Medical Genetics Clinic, Mersin Women and Children Hospital, Mersin 33330, Turkey
| | - Ozturk Ozdemir
- Department of Medical Genetics, Faculty of Medicine, Onsekiz Mart University, Canakkale 17000, Turkey
| | - Fatma Silan
- Department of Medical Genetics, Faculty of Medicine, Onsekiz Mart University, Canakkale 17000, Turkey
| | - Onur Yildiz
- Department of Medical Genetics, Faculty of Medicine, Onsekiz Mart University, Canakkale 17000, Turkey
| | - Osman Yesilbas
- Division of Critical Care Medicine, Department of Pediatrics, University of Health Sciences, Van Training and Research Hospital, Van 65130, Turkey
| | - Sedat Isikay
- Department of Physiotherapy and Rehabilitation, Hasan Kalyoncu University, School of Health Sciences, Gaziantep 27000, Turkey
| | - Burhan Balta
- Department of Medical Genetics, Kayseri Training and Research Hospital, Kayseri 38080, Turkey
| | - Shen Gu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Shalini N Jhangiani
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Harsha Doddapaneni
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jianhong Hu
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Donna M Muzny
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Eric Boerwinkle
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA; Human Genetics Center, University of Texas Health Science Center at Houston School of Public Health, Houston, TX, USA
| | - Richard A Gibbs
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Konstantinos Tsiakas
- Department of Pediatrics, University Medical Center Hamburg-Eppendorf, Hamburg, 20246, Germany
| | - Maja Hempel
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Martinistraße 52, Hamburg 20246, Germany
| | - Katta Mohan Girisha
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal 576104, India
| | - Davut Gul
- Department of Medical Genetics, Gulhane Military Medical School, Ankara 06010, Turkey
| | - Jennifer E Posey
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Nursel H Elcioglu
- Department of Pediatric Genetics, Marmara University Medical School, Istanbul 34854, Turkey; Eastern Mediterranean University School of Medicine, Cyprus, Mersin 10, Turkey
| | - Beyhan Tuysuz
- Department of Pediatric Genetics, Istanbul University-Cerrahpasa Medical Faculty, Istanbul 34096, Turkey
| | - James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA; Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA; Texas Children's Hospital, Houston, TX 77030, USA.
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30
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Liu CH, Rasband MN. Axonal Spectrins: Nanoscale Organization, Functional Domains and Spectrinopathies. Front Cell Neurosci 2019; 13:234. [PMID: 31191255 PMCID: PMC6546920 DOI: 10.3389/fncel.2019.00234] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 05/09/2019] [Indexed: 11/13/2022] Open
Abstract
Spectrin cytoskeletons are found in all metazoan cells, and their physical interactions between actin and ankyrins establish a meshwork that provides cellular structural integrity. With advanced super-resolution microscopy, the intricate spatial organization and associated functional properties of these cytoskeletons can now be analyzed with unprecedented clarity. Long neuronal processes like peripheral sensory and motor axons may be subject to intense mechanical forces including bending, stretching, and torsion. The spectrin-based cytoskeleton is essential to protect axons against these mechanical stresses. Additionally, spectrins are critical for the assembly and maintenance of axonal excitable domains including the axon initial segment and the nodes of Ranvier (NoR). These sites facilitate rapid and efficient action potential initiation and propagation in the nervous system. Recent studies revealed that pathogenic spectrin variants and diseases that protealyze and breakdown spectrins are associated with congenital neurological disorders and nervous system injury. Here, we review recent studies of spectrins in the nervous system and focus on their functions in axonal health and disease.
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Affiliation(s)
- Cheng-Hsin Liu
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX, United States
| | - Matthew Neil Rasband
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX, United States.,Department of Neuroscience, Baylor College of Medicine, Houston, TX, United States
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31
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Tomar S, Sethi R, Lai PS. Specific phenotype semantics facilitate gene prioritization in clinical exome sequencing. Eur J Hum Genet 2019; 27:1389-1397. [PMID: 31053788 DOI: 10.1038/s41431-019-0412-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 02/21/2019] [Accepted: 04/15/2019] [Indexed: 12/13/2022] Open
Abstract
Selection and prioritization of phenotype-centric variants remains a challenging part of variant analysis and interpretation in clinical exome sequencing. Phenotype-driven shortlisting of patient-specific gene lists can avoid missed diagnosis. Here, we analyzed the relevance of using primary Human Phenotype Ontology identifiers (HPO IDs) in prioritizing Mendelian disease genes across 30 in-house, 10 previously reported, and 10 recently published cases using three popular web-based gene prioritization tools (OMIMExplorer, VarElect & Phenolyzer). We assessed partial HPO-based gene prioritization using randomly chosen and top 10%, 30%, and 50% HPO IDs based on information content and found high variance within rank ratios across the former vs the latter. This signified that randomly selected less-specific HPO IDs for a given disease phenotype performed poorly by ranking probe gene farther away from the top rank. In contrast, the use of top 10%, 30%, and 50% HPO IDs individually could rank the probe gene among the top 1% in the ranked list of genes that was equivalent to the results when the full list of HPO IDs were used. Hence, we conclude that use of just the top 10% of HPO IDs chosen based on information content is sufficient for ranking the probe gene at top position. Our findings provide practical guidance for utilizing structured phenotype semantics and web-based gene-ranking tools to aid in identifying known as well unknown candidate gene associations in Mendelian disorders.
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Affiliation(s)
- Swati Tomar
- Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System (NUHS), 1E Kent Ridge Road, 119228, Singapore
| | - Raman Sethi
- Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System (NUHS), 1E Kent Ridge Road, 119228, Singapore
| | - Poh San Lai
- Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System (NUHS), 1E Kent Ridge Road, 119228, Singapore.
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32
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Abstract
Congenital myopathies (CM) are a large and heterogeneous group of disorders. Many new myopathies with congenital onset have recently been described phenotypically, and their molecular elucidation has rapidly ensued consecutively. CM reported between 2013 and 2017 and their corresponding gene defects have mostly been identified with modern molecular genetic techniques. Here, we report recently identified CM that have not been included in the 2017 gene table so far, of which some have been recognized with mutations in new genes and others have been recognized as variants of previously identified genes, associated with specific CM phenotypes.
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Affiliation(s)
- Josefine Radke
- Department of Neuropathology, Charité-Universitätsmedizin Berlin, Berlin, Germany.
| | - Werner Stenzel
- Department of Neuropathology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Hans H Goebel
- Department of Neuropathology, Charité-Universitätsmedizin Berlin, Berlin, Germany
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33
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Baker SW, Murrell JR, Nesbitt AI, Pechter KB, Balciuniene J, Zhao X, Yu Z, Denenberg EH, DeChene ET, Wilkens AB, Bhoj EJ, Guan Q, Dulik MC, Conlin LK, Abou Tayoun AN, Luo M, Wu C, Cao K, Sarmady M, Bedoukian EC, Tarpinian J, Medne L, Skraban CM, Deardorff MA, Krantz ID, Krock BL, Santani AB. Automated Clinical Exome Reanalysis Reveals Novel Diagnoses. J Mol Diagn 2019; 21:38-48. [DOI: 10.1016/j.jmoldx.2018.07.008] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 06/19/2018] [Accepted: 07/30/2018] [Indexed: 10/27/2022] Open
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34
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Reorganization of Destabilized Nodes of Ranvier in β IV Spectrin Mutants Uncovers Critical Timelines for Nodal Restoration and Prevention of Motor Paresis. J Neurosci 2018; 38:6267-6282. [PMID: 29907663 DOI: 10.1523/jneurosci.0515-18.2018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 05/14/2018] [Accepted: 06/05/2018] [Indexed: 11/21/2022] Open
Abstract
Disorganization of nodes of Ranvier is associated with motor and sensory dysfunctions. Mechanisms that allow nodal recovery during pathological processes remain poorly understood. A highly enriched nodal cytoskeletal protein βIV spectrin anchors and stabilizes the nodal complex to actin cytoskeleton. Loss of murine βIV spectrin allows the initial nodal organization, but causes gradual nodal destabilization. Mutations in human βIV spectrin cause auditory neuropathy and impairment in motor coordination. Similar phenotypes are caused by nodal disruption due to demyelination. Here we report on the precise timelines of nodal disorganization and reorganization by following disassembly and reassembly of key nodal proteins in βIV spectrin mice of both sexes before and after βIV spectrin re-expression at specifically chosen developmental time points. We show that the timeline of nodal restoration has different outcomes in the PNS and CNS with respect to nodal reassembly and functional restoration. In the PNS, restoration of nodes occurs within 1 month regardless of the time of βIV spectrin re-expression. In contrast, the CNS nodal reorganization and functional restoration occurs within a critical time window; after that, nodal reorganization diminishes, leading to less efficient motor recovery. We demonstrate that timely restoration of nodes can improve both the functional properties and the ultrastructure of myelinated fibers affected by long-term nodal disorganization. Our studies, which indicate a critical timeline for nodal restoration together with overall motor performance and prolonged life span, further support the idea that nodal restoration is more beneficial if initiated before any axonal damage, which is critically relevant to demyelinating disorders.SIGNIFICANCE STATEMENT Nodes of Ranvier are integral to efficient and rapid signal transmission along myelinated fibers. Various demyelinating disorders are characterized by destabilization of the nodal molecular complex, accompanied by severe reduction in nerve conduction and the onset of motor and sensory dysfunctions. This study is the first to report in vivo reassembly of destabilized nodes with sequential improvement in overall motor performance. Our study reveals that nodal restoration is achievable before any axonal damage, and that long-term nodal destabilization causes irreversible axonal structural changes that prevent functional restoration. Our studies provide significant insights into timely restoration of nodal domains as a potential therapeutic approach in treatment of demyelinating disorders.
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35
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Wang CC, Ortiz-González XR, Yum SW, Gill SM, White A, Kelter E, Seaver LH, Lee S, Wiley G, Gaffney PM, Wierenga KJ, Rasband MN. βIV Spectrinopathies Cause Profound Intellectual Disability, Congenital Hypotonia, and Motor Axonal Neuropathy. Am J Hum Genet 2018; 102:1158-1168. [PMID: 29861105 PMCID: PMC5992132 DOI: 10.1016/j.ajhg.2018.04.012] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 04/24/2018] [Indexed: 12/31/2022] Open
Abstract
βIV spectrin links ankyrinG (AnkG) and clustered ion channels at axon initial segments (AISs) and nodes of Ranvier to the axonal cytoskeleton. Here, we report bi-allelic pathogenic SPTBN4 variants (three homozygous and two compound heterozygous) that cause a severe neurological syndrome that includes congenital hypotonia, intellectual disability, and motor axonal and auditory neuropathy. We introduced these variants into βIV spectrin, expressed these in neurons, and found that 5/7 were loss-of-function variants disrupting AIS localization or abolishing phosphoinositide binding. Nerve biopsies from an individual with a loss-of-function variant had reduced nodal Na+ channels and no nodal KCNQ2 K+ channels. Modeling the disease in mice revealed that although ankyrinR (AnkR) and βI spectrin can cluster Na+ channels and partially compensate for the loss of AnkG and βIV spectrin at nodes of Ranvier, AnkR and βI spectrin cannot cluster KCNQ2- and KCNQ3-subunit-containing K+ channels. Our findings define a class of spectrinopathies and reveal the molecular pathologies causing nervous-system dysfunction.
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Affiliation(s)
- Chih-Chuan Wang
- Department of Neuroscience and Integrative Molecular and Biomedical Sciences Graduate Program, Baylor College of Medicine, Houston, TX 77030, USA
| | - Xilma R Ortiz-González
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Division of Neurology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Sabrina W Yum
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Division of Neurology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Sara M Gill
- Department of Audiology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Amy White
- Department of Audiology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Erin Kelter
- Women and Children's Hospital of Buffalo, Buffalo, NY 14203, USA
| | - Laurie H Seaver
- Spectrum Health Medical Genetics, MSU College of Human Medicine, Department of Pediatrics and Human Development, Grand Rapids, MI 49503, USA
| | - Sansan Lee
- Hawai'i Community Genetics, Honolulu, HI 96814, USA
| | - Graham Wiley
- Division of Genomics and Data Sciences, Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104, USA
| | - Patrick M Gaffney
- Division of Genomics and Data Sciences, Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104, USA
| | - Klaas J Wierenga
- Department of Pediatrics, Oklahoma University Health Sciences Center, Oklahoma City, OK 73104, USA.
| | - Matthew N Rasband
- Department of Neuroscience and Integrative Molecular and Biomedical Sciences Graduate Program, Baylor College of Medicine, Houston, TX 77030, USA.
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36
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Huang CYM, Rasband MN. Axon initial segments: structure, function, and disease. Ann N Y Acad Sci 2018; 1420:46-61. [PMID: 29749636 DOI: 10.1111/nyas.13718] [Citation(s) in RCA: 106] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 03/13/2018] [Accepted: 03/17/2018] [Indexed: 11/28/2022]
Abstract
The axon initial segment (AIS) is located at the proximal axon and is the site of action potential initiation. This reflects the high density of ion channels found at the AIS. Adaptive changes to the location and length of the AIS can fine-tune the excitability of neurons and modulate plasticity in response to activity. The AIS plays an important role in maintaining neuronal polarity by regulating the trafficking and distribution of proteins that function in somatodendritic or axonal compartments of the neuron. In this review, we provide an overview of the AIS cytoarchitecture, mechanism of assembly, and recent studies revealing mechanisms of differential transport at the AIS that maintain axon and dendrite identities. We further discuss how genetic mutations in AIS components (i.e., ankyrins, ion channels, and spectrins) and injuries may cause neurological disorders.
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Affiliation(s)
| | - Matthew N Rasband
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas
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37
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Hund TJ, Unudurthi SD, Greer-Short A, Patel N, Nassal D. Spectrin-based pathways underlying electrical and mechanical dysfunction in cardiac disease. Expert Rev Cardiovasc Ther 2018; 16:59-65. [PMID: 29257730 PMCID: PMC6064643 DOI: 10.1080/14779072.2018.1418664] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
INTRODUCTION In the heart, pathways that transduce extracellular environmental cues (e.g. mechanical force, inflammatory stress) into electrical and/or chemical signals at the cellular level are critical for the organ-level response to chronic biomechanical/neurohumoral stress. Specifically, a diverse array of membrane-bound receptors and stretch-activated proteins converge on a network of intracellular signaling cascades that control gene expression, protein translation, degradation and/or regulation. These cellular reprogramming events ultimately lead to changes in cell excitability, growth, proliferation, and/or survival. Areas covered: The actin/spectrin cytoskeleton has emerged as having important roles in not only providing structural support for organelle function but also in serving as a signaling 'superhighway,' linking signaling events at/near the membrane to distal cellular domains (e.g. nucleus, mitochondria). Furthermore, recent work suggests that the integrity of the actin/spectrin cytoskeleton is critical for canonical signaling of pathways involved in cellular response to stress. This review discusses these emerging roles for spectrin and consider implications for heart function and disease. Expert commentary: Despite growth in our understanding of the broader roles for spectrins in cardiac myocytes and other metazoan cells, there remain important unanswered questions, the answers to which may point the way to new therapies for human cardiac disease patients.
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Affiliation(s)
- Thomas J. Hund
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, The Ohio State University, Columbus OH 43210
- Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus OH 43210
- Department of Internal Medicine, The Ohio State University Wexner Medical Center, The Ohio State University, Columbus OH 43210
| | - Sathya D. Unudurthi
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, The Ohio State University, Columbus OH 43210
- Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus OH 43210
| | - Amara Greer-Short
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, The Ohio State University, Columbus OH 43210
- Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus OH 43210
| | - Nehal Patel
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, The Ohio State University, Columbus OH 43210
- Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus OH 43210
| | - Drew Nassal
- The Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, The Ohio State University, Columbus OH 43210
- Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus OH 43210
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38
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Cassandrini D, Trovato R, Rubegni A, Lenzi S, Fiorillo C, Baldacci J, Minetti C, Astrea G, Bruno C, Santorelli FM. Congenital myopathies: clinical phenotypes and new diagnostic tools. Ital J Pediatr 2017; 43:101. [PMID: 29141652 PMCID: PMC5688763 DOI: 10.1186/s13052-017-0419-z] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 11/02/2017] [Indexed: 12/26/2022] Open
Abstract
Congenital myopathies are a group of genetic muscle disorders characterized clinically by hypotonia and weakness, usually from birth, and a static or slowly progressive clinical course. Historically, congenital myopathies have been classified on the basis of major morphological features seen on muscle biopsy. However, different genes have now been identified as associated with the various phenotypic and histological expressions of these disorders, and in recent years, because of their unexpectedly wide genetic and clinical heterogeneity, next-generation sequencing has increasingly been used for their diagnosis. We reviewed clinical and genetic forms of congenital myopathy and defined possible strategies to improve cost-effectiveness in histological and imaging diagnosis.
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Affiliation(s)
| | - Rosanna Trovato
- Molecular Medicine, IRCCS Fondazione Stella Maris, Pisa, Italy
| | - Anna Rubegni
- Molecular Medicine, IRCCS Fondazione Stella Maris, Pisa, Italy
| | - Sara Lenzi
- Neurology, IRCCS Fondazione Stella Maris, Pisa, Italy
| | - Chiara Fiorillo
- Molecular Medicine, IRCCS Fondazione Stella Maris, Pisa, Italy.,Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Genoa, Italy
| | - Jacopo Baldacci
- Molecular Medicine, IRCCS Fondazione Stella Maris, Pisa, Italy
| | - Carlo Minetti
- Unit of Pediatric Neurology and Muscular Disorders, Istituto G. Gaslini, Genoa, Italy.,Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Genoa, Italy
| | - Guja Astrea
- Neurology, IRCCS Fondazione Stella Maris, Pisa, Italy
| | - Claudio Bruno
- Department of Neuroscience, Center of Myology and Neurodegenerative Disorders, Istituto G. Gaslini, Genoa, Italy
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αII Spectrin Forms a Periodic Cytoskeleton at the Axon Initial Segment and Is Required for Nervous System Function. J Neurosci 2017; 37:11311-11322. [PMID: 29038240 DOI: 10.1523/jneurosci.2112-17.2017] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 09/11/2017] [Accepted: 10/04/2017] [Indexed: 01/02/2023] Open
Abstract
Spectrins form a submembranous cytoskeleton proposed to confer strength and flexibility to neurons and to participate in ion channel clustering at axon initial segments (AIS) and nodes of Ranvier. Neuronal spectrin cytoskeletons consist of diverse β subunits and αII spectrin. Although αII spectrin is found in neurons in both axonal and somatodendritic domains, using proteomics, biochemistry, and superresolution microscopy, we show that αII and βIV spectrin interact and form a periodic AIS cytoskeleton. To determine the role of spectrins in the nervous system, we generated Sptan1f/f mice for deletion of CNS αII spectrin. We analyzed αII spectrin-deficient mice of both sexes and found that loss of αII spectrin causes profound reductions in all β spectrins. αII spectrin-deficient mice die before 1 month of age and have disrupted AIS and many other neurological impairments including seizures, disrupted cortical lamination, and widespread neurodegeneration. These results demonstrate the importance of the spectrin cytoskeleton both at the AIS and throughout the nervous system.SIGNIFICANCE STATEMENT Spectrin cytoskeletons play diverse roles in neurons, including assembly of excitable domains such as the axon initial segment (AIS) and nodes of Ranvier. However, the molecular composition and structure of these cytoskeletons remain poorly understood. Here, we show that αII spectrin partners with βIV spectrin to form a periodic cytoskeleton at the AIS. Using a new αII spectrin conditional knock-out mouse, we show that αII spectrin is required for AIS assembly, neuronal excitability, cortical lamination, and to protect against neurodegeneration. These results demonstrate the broad importance of spectrin cytoskeletons for nervous system function and development and have important implications for nervous system injuries and diseases because disruption of the spectrin cytoskeleton is a common molecular pathology.
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40
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Anazi S, Maddirevula S, Salpietro V, Asi YT, Alsahli S, Alhashem A, Shamseldin HE, AlZahrani F, Patel N, Ibrahim N, Abdulwahab FM, Hashem M, Alhashmi N, Al Murshedi F, Al Kindy A, Alshaer A, Rumayyan A, Al Tala S, Kurdi W, Alsaman A, Alasmari A, Banu S, Sultan T, Saleh MM, Alkuraya H, Salih MA, Aldhalaan H, Ben-Omran T, Al Musafri F, Ali R, Suleiman J, Tabarki B, El-Hattab AW, Bupp C, Alfadhel M, Al Tassan N, Monies D, Arold ST, Abouelhoda M, Lashley T, Houlden H, Faqeih E, Alkuraya FS. Expanding the genetic heterogeneity of intellectual disability. Hum Genet 2017; 136:1419-1429. [PMID: 28940097 DOI: 10.1007/s00439-017-1843-2] [Citation(s) in RCA: 101] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 09/15/2017] [Indexed: 11/30/2022]
Abstract
Intellectual disability (ID) is a common morbid condition with a wide range of etiologies. The list of monogenic forms of ID has increased rapidly in recent years thanks to the implementation of genomic sequencing techniques. In this study, we describe the phenotypic and genetic findings of 68 families (105 patients) all with novel ID-related variants. In addition to established ID genes, including ones for which we describe unusual mutational mechanism, some of these variants represent the first confirmatory disease-gene links following previous reports (TRAK1, GTF3C3, SPTBN4 and NKX6-2), some of which were based on single families. Furthermore, we describe novel variants in 14 genes that we propose as novel candidates (ANKHD1, ASTN2, ATP13A1, FMO4, MADD, MFSD11, NCKAP1, NFASC, PCDHGA10, PPP1R21, SLC12A2, SLK, STK32C and ZFAT). We highlight MADD and PCDHGA10 as particularly compelling candidates in which we identified biallelic likely deleterious variants in two independent ID families each. We also highlight NCKAP1 as another compelling candidate in a large family with autosomal dominant mild intellectual disability that fully segregates with a heterozygous truncating variant. The candidacy of NCKAP1 is further supported by its biological function, and our demonstration of relevant expression in human brain. Our study expands the locus and allelic heterogeneity of ID and demonstrates the power of positional mapping to reveal unusual mutational mechanisms.
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Affiliation(s)
- Shams Anazi
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Sateesh Maddirevula
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Vincenzo Salpietro
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
| | - Yasmine T Asi
- Queen Square Brain Bank for Neurological Disorders, Department of Molecular Neuroscience, UCL Institute of Neurology, University College London, London, UK
| | - Saud Alsahli
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Amal Alhashem
- Department of Pediatrics, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - Hanan E Shamseldin
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Fatema AlZahrani
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Nisha Patel
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Niema Ibrahim
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Firdous M Abdulwahab
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Mais Hashem
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Nadia Alhashmi
- Department of Genetics, College of Medicine, Sultan Qaboos University, Muscat, Sultanate of Oman
| | - Fathiya Al Murshedi
- Department of Genetics, College of Medicine, Sultan Qaboos University, Muscat, Sultanate of Oman
| | - Adila Al Kindy
- Department of Genetics, College of Medicine, Sultan Qaboos University, Muscat, Sultanate of Oman
| | - Ahmad Alshaer
- Pediatric Neurology, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Ahmed Rumayyan
- King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia.,Neurology Division, Department of Pediatrics, King Abdulaziz Medical City, Riyadh, Saudi Arabia
| | - Saeed Al Tala
- Department of Pediatrics and Genetic Unit, Armed Forces Hospital, Khamis Mushayt, Saudi Arabia
| | - Wesam Kurdi
- Department of Obstetrics and Gynecology, King Faisal Specialist Hospital, Riyadh, Saudi Arabia
| | - Abdulaziz Alsaman
- Department of Pediatric Subspecialties, Children's Hospital, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Ali Alasmari
- Department of Pediatric Subspecialties, Children's Hospital, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Selina Banu
- Department of Pediatric Neurology, ICH and SSF Hospital Mirpur, Dhaka, 1216, Bangladesh
| | - Tipu Sultan
- Department of Pediatric Neurology, Institute of Child Health and The Children's Hospital Lahore, 381-D/2, Lahore, Pakistan
| | - Mohammed M Saleh
- Department of Pediatric Subspecialties, Children's Hospital, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Hisham Alkuraya
- Department of Ophthalmology, Specialized Medical Center Hospital, Riyadh, Saudi Arabia
| | - Mustafa A Salih
- Division of Pediatric Neurology, Department of Pediatrics, King Khalid University Hospital and College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Hesham Aldhalaan
- Pediatric Neurology, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Tawfeg Ben-Omran
- Clinical and Metabolic Genetics, Department of Pediatrics, Hamad Medical Corporation, Doha, Qatar
| | - Fatima Al Musafri
- Clinical and Metabolic Genetics, Department of Pediatrics, Hamad Medical Corporation, Doha, Qatar
| | - Rehab Ali
- Clinical and Metabolic Genetics, Department of Pediatrics, Hamad Medical Corporation, Doha, Qatar
| | - Jehan Suleiman
- Division of Neurology, Department of Pediatrics, Tawam Hospital, Al Ain, United Arab Emirates
| | - Brahim Tabarki
- Department of Pediatrics, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - Ayman W El-Hattab
- Division of Clinical Genetics and Metabolic Disorders, Department of Pediatrics, Tawam Hospital, Al-Ain, United Arab Emirates
| | - Caleb Bupp
- Spectrum Health Genetics, Grand Rapids, MI, USA
| | - Majid Alfadhel
- Genetics Division, Department of Pediatrics, King Abdullah International Medical Research Centre, King Saud bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Riyadh, Saudi Arabia
| | - Nada Al Tassan
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.,Saudi Human Genome Program, King Abdulaziz City for Science and Technology, Riyadh, Saudi Arabia
| | - Dorota Monies
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.,Saudi Human Genome Program, King Abdulaziz City for Science and Technology, Riyadh, Saudi Arabia
| | - Stefan T Arold
- Division of Biological and Environmental Sciences and Engineering (BESE), Computational Bioscience Research Center (CBRC), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Mohamed Abouelhoda
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.,Saudi Human Genome Program, King Abdulaziz City for Science and Technology, Riyadh, Saudi Arabia
| | - Tammaryn Lashley
- Queen Square Brain Bank for Neurological Disorders, Department of Molecular Neuroscience, UCL Institute of Neurology, University College London, London, UK
| | - Henry Houlden
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
| | - Eissa Faqeih
- Department of Pediatric Subspecialties, Children's Hospital, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Fowzan S Alkuraya
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia. .,Department of Pediatrics, Prince Sultan Military Medical City, Riyadh, Saudi Arabia. .,Saudi Human Genome Program, King Abdulaziz City for Science and Technology, Riyadh, Saudi Arabia. .,Spectrum Health Genetics, Grand Rapids, MI, USA. .,Division of Biological and Environmental Sciences and Engineering (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia.
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