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Zhu CH, Yu JY, Ma Y, Dong Y, Wu ZY. Progressive Ataxia due to de novo Missense Variants in the CACNA1A Gene. CEREBELLUM (LONDON, ENGLAND) 2024:10.1007/s12311-024-01710-0. [PMID: 38869769 DOI: 10.1007/s12311-024-01710-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 06/04/2024] [Indexed: 06/14/2024]
Abstract
The CACNA1A gene encodes the alpha-1A subunit of P/Q type voltage-gated calcium channel Cav2.1, which is associated with a broad clinical spectrum and variable symptomatology. While few patients with progressive ataxia caused by CACNA1A missense variants have been reported, here we report three unrelated Chinese patients with progressive ataxia due to de novo missense variants in the CACNA1A gene, including a novel pathogenic variant (c.4999C > G) and a previously reported pathogenic variant (c.4037G > A). Our findings and a systematic literature review show the unique phenotype of progressive ataxia caused by missense variants and enlarge the genetic and clinical spectrum of CACNA1A. This suggests that in addition to routine screening for dynamic mutations, screening for CACNA1A variants is important for clinicians facing patients with progressive ataxia.
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Affiliation(s)
- Chen-Hao Zhu
- Department of Medical Genetics and Center for Rare Diseases and Department of Neurology, the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Rd, Hangzhou, 310009, China
| | - Jin-Yang Yu
- Department of Medical Genetics and Center for Rare Diseases and Department of Neurology, the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Rd, Hangzhou, 310009, China
| | - Yin Ma
- Department of Medical Genetics and Center for Rare Diseases and Department of Neurology, the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Rd, Hangzhou, 310009, China
| | - Yi Dong
- Department of Medical Genetics and Center for Rare Diseases and Department of Neurology, the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Rd, Hangzhou, 310009, China
| | - Zhi-Ying Wu
- Department of Medical Genetics and Center for Rare Diseases and Department of Neurology, the Second Affiliated Hospital, Zhejiang University School of Medicine, 88 Jiefang Rd, Hangzhou, 310009, China.
- Nanhu Brain-Computer Interface Institute, Hangzhou, China.
- MOE Frontier Science Center for Brain Science and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China.
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2
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Li S, Zhao S, Sinson JC, Bajic A, Rosenfeld JA, Neeley MB, Pena M, Worley KC, Burrage LC, Weisz-Hubshman M, Ketkar S, Craigen WJ, Clark GD, Lalani S, Bacino CA, Machol K, Chao HT, Potocki L, Emrick L, Sheppard J, Nguyen MTT, Khoramnia A, Hernandez PP, Nagamani SC, Liu Z, Eng CM, Lee B, Liu P. The clinical utility and diagnostic implementation of human subject cell transdifferentiation followed by RNA sequencing. Am J Hum Genet 2024; 111:841-862. [PMID: 38593811 PMCID: PMC11080285 DOI: 10.1016/j.ajhg.2024.03.007] [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: 10/04/2023] [Revised: 03/08/2024] [Accepted: 03/11/2024] [Indexed: 04/11/2024] Open
Abstract
RNA sequencing (RNA-seq) has recently been used in translational research settings to facilitate diagnoses of Mendelian disorders. A significant obstacle for clinical laboratories in adopting RNA-seq is the low or absent expression of a significant number of disease-associated genes/transcripts in clinically accessible samples. As this is especially problematic in neurological diseases, we developed a clinical diagnostic approach that enhanced the detection and evaluation of tissue-specific genes/transcripts through fibroblast-to-neuron cell transdifferentiation. The approach is designed specifically to suit clinical implementation, emphasizing simplicity, cost effectiveness, turnaround time, and reproducibility. For clinical validation, we generated induced neurons (iNeurons) from 71 individuals with primary neurological phenotypes recruited to the Undiagnosed Diseases Network. The overall diagnostic yield was 25.4%. Over a quarter of the diagnostic findings benefited from transdifferentiation and could not be achieved by fibroblast RNA-seq alone. This iNeuron transcriptomic approach can be effectively integrated into diagnostic whole-transcriptome evaluation of individuals with genetic disorders.
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Affiliation(s)
- Shenglan Li
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Sen Zhao
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Jefferson C Sinson
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Aleksandar Bajic
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX, USA; Advanced Technology Cores, Baylor College of Medicine, Houston, TX, USA
| | - Jill A Rosenfeld
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Matthew B Neeley
- Graduate Program in Quantitative and Computational Biosciences, Baylor College of Medicine, Houston, TX, USA
| | - Mezthly Pena
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Kim C Worley
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Lindsay C Burrage
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Texas Children's Hospital, Houston, TX, USA
| | - Monika Weisz-Hubshman
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Texas Children's Hospital, Houston, TX, USA
| | - Shamika Ketkar
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - William J Craigen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Texas Children's Hospital, Houston, TX, USA
| | - Gary D Clark
- Department of Pediatrics, Section of Neurology, Baylor College of Medicine, Houston, TX, USA; Texas Children's Hospital, Houston, TX, USA
| | - Seema Lalani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Texas Children's Hospital, Houston, TX, USA
| | - Carlos A Bacino
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Texas Children's Hospital, Houston, TX, USA
| | - Keren Machol
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Texas Children's Hospital, Houston, TX, USA
| | - Hsiao-Tuan Chao
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX, USA; Department of Pediatrics, Section of Neurology, Baylor College of Medicine, Houston, TX, USA; Texas Children's Hospital, Houston, TX, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA; Cain Pediatric Research Foundation Laboratories, Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX, USA; McNair Medical Institute, The Robert and Janice McNair Foundation, Houston, TX, USA
| | - Lorraine Potocki
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Texas Children's Hospital, Houston, TX, USA
| | - Lisa Emrick
- Department of Pediatrics, Section of Neurology, Baylor College of Medicine, Houston, TX, USA; Texas Children's Hospital, Houston, TX, USA
| | - Jennifer Sheppard
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX, USA; Department of Pediatrics, Section of Neurology, Baylor College of Medicine, Houston, TX, USA
| | - My T T Nguyen
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX, USA
| | - Anahita Khoramnia
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | | | - Sandesh Cs Nagamani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Texas Children's Hospital, Houston, TX, USA
| | - Zhandong Liu
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX, USA; Graduate Program in Quantitative and Computational Biosciences, Baylor College of Medicine, Houston, TX, USA; Department of Pediatrics, Section of Neurology, Baylor College of Medicine, Houston, TX, USA
| | - Christine M Eng
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Baylor Genetics, Houston, TX, USA
| | - Brendan Lee
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Texas Children's Hospital, Houston, TX, USA
| | - Pengfei Liu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Baylor Genetics, Houston, TX, USA.
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Complex effects on Ca V2.1 channel gating caused by a CACNA1A variant associated with a severe neurodevelopmental disorder. Sci Rep 2022; 12:9186. [PMID: 35655070 PMCID: PMC9163077 DOI: 10.1038/s41598-022-12789-y] [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: 01/13/2022] [Accepted: 05/16/2022] [Indexed: 01/25/2023] Open
Abstract
P/Q-type Ca2+ currents mediated by CaV2.1 channels are essential for active neurotransmitter release at neuromuscular junctions and many central synapses. Mutations in CACNA1A, the gene encoding the principal CaV2.1 α1A subunit, cause a broad spectrum of neurological disorders. Typically, gain-of-function (GOF) mutations are associated with migraine and epilepsy while loss-of-function (LOF) mutations are causative for episodic and congenital ataxias. However, a cluster of severe CaV2.1 channelopathies have overlapping presentations which suggests that channel dysfunction in these disorders cannot always be defined bimodally as GOF or LOF. In particular, the R1667P mutation causes focal seizures, generalized hypotonia, dysarthria, congenital ataxia and, in one case, cerebral edema leading ultimately to death. Here, we demonstrate that the R1667P mutation causes both channel GOF (hyperpolarizing voltage-dependence of activation, slowed deactivation) and LOF (slowed activation kinetics) when expressed heterologously in tsA-201 cells. We also observed a substantial reduction in Ca2+ current density in this heterologous system. These changes in channel gating and availability/expression manifested in diminished Ca2+ flux during action potential-like stimuli. However, the integrated Ca2+ fluxes were no different when normalized to tail current amplitude measured upon repolarization from the reversal potential. In summary, our findings indicate a complex functional effect of R1667P and support the idea that pathological missense mutations in CaV2.1 may not represent exclusively GOF or LOF.
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Martínez-Monseny AF, Edo A, Casas-Alba D, Izquierdo-Serra M, Bolasell M, Conejo D, Martorell L, Muchart J, Carrera L, Ortez CI, Nascimento A, Oliva B, Fernández-Fernández JM, Serrano M. CACNA1A Mutations Causing Early Onset Ataxia: Profiling Clinical, Dysmorphic and Structural-Functional Findings. Int J Mol Sci 2021; 22:ijms22105180. [PMID: 34068417 PMCID: PMC8153625 DOI: 10.3390/ijms22105180] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 05/11/2021] [Accepted: 05/12/2021] [Indexed: 01/07/2023] Open
Abstract
The CACNA1A gene encodes the pore-forming α1A subunit of the voltage-gated CaV2.1 Ca2+ channel, essential in neurotransmission, especially in Purkinje cells. Mutations in CACNA1A result in great clinical heterogeneity with progressive symptoms, paroxysmal events or both. During infancy, clinical and neuroimaging findings may be unspecific, and no dysmorphic features have been reported. We present the clinical, radiological and evolutionary features of three patients with congenital ataxia, one of them carrying a new variant. We report the structural localization of variants and their expected functional consequences. There was an improvement in cerebellar syndrome over time despite a cerebellar atrophy progression, inconsistent response to acetazolamide and positive response to methylphenidate. The patients shared distinctive facial gestalt: oval face, prominent forehead, hypertelorism, downslanting palpebral fissures and narrow nasal bridge. The two α1A affected residues are fully conserved throughout evolution and among the whole human CaV channel family. They contribute to the channel pore and the voltage sensor segment. According to structural data analysis and available functional characterization, they are expected to exert gain- (F1394L) and loss-of-function (R1664Q/R1669Q) effect, respectively. Among the CACNA1A-related phenotypes, our results suggest that non-progressive congenital ataxia is associated with developmental delay and dysmorphic features, constituting a recognizable syndromic neurodevelopmental disorder.
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Affiliation(s)
- Antonio F. Martínez-Monseny
- Department of Genetic and Molecular Medicine, Institut de Recerca, Hospital Sant Joan de Déu, 08950 Barcelona, Spain; (A.F.M.-M.); (D.C.-A.); (M.B.); (L.M.)
| | - Albert Edo
- Laboratory of Molecular Physiology, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, 08003 Barcelona, Spain; (A.E.); (M.I.-S.)
| | - Dídac Casas-Alba
- Department of Genetic and Molecular Medicine, Institut de Recerca, Hospital Sant Joan de Déu, 08950 Barcelona, Spain; (A.F.M.-M.); (D.C.-A.); (M.B.); (L.M.)
| | - Mercè Izquierdo-Serra
- Laboratory of Molecular Physiology, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, 08003 Barcelona, Spain; (A.E.); (M.I.-S.)
| | - Mercè Bolasell
- Department of Genetic and Molecular Medicine, Institut de Recerca, Hospital Sant Joan de Déu, 08950 Barcelona, Spain; (A.F.M.-M.); (D.C.-A.); (M.B.); (L.M.)
| | - David Conejo
- Pediatric Department, Complejo Asistencial de Burgos, 09006 Burgos, Spain;
| | - Loreto Martorell
- Department of Genetic and Molecular Medicine, Institut de Recerca, Hospital Sant Joan de Déu, 08950 Barcelona, Spain; (A.F.M.-M.); (D.C.-A.); (M.B.); (L.M.)
- U-703 Centre for Biomedical Research on Rare Diseases (CIBER-ER), Instituto de Salud Carlos III, 08002 Barcelona, Spain; (C.I.O.); (A.N.)
| | - Jordi Muchart
- Pediatric Radiology Department, Institut de Recerca Sant Joan de Déu, Hospital Sant Joan de Déu, 08950 Barcelona, Spain;
| | - Laura Carrera
- Neuropediatric Department, Institut de Recerca Sant Joan de Déu, Hospital Sant Joan de Déu, 08950 Barcelona, Spain;
| | - Carlos I. Ortez
- U-703 Centre for Biomedical Research on Rare Diseases (CIBER-ER), Instituto de Salud Carlos III, 08002 Barcelona, Spain; (C.I.O.); (A.N.)
- Neuropediatric Department, Institut de Recerca Sant Joan de Déu, Hospital Sant Joan de Déu, 08950 Barcelona, Spain;
| | - Andrés Nascimento
- U-703 Centre for Biomedical Research on Rare Diseases (CIBER-ER), Instituto de Salud Carlos III, 08002 Barcelona, Spain; (C.I.O.); (A.N.)
- Neuropediatric Department, Institut de Recerca Sant Joan de Déu, Hospital Sant Joan de Déu, 08950 Barcelona, Spain;
| | - Baldo Oliva
- Structural Bioinformatics Lab, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, 08003 Barcelona, Spain;
| | - José M. Fernández-Fernández
- Laboratory of Molecular Physiology, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, 08003 Barcelona, Spain; (A.E.); (M.I.-S.)
- Correspondence: (J.M.F.-F.); (M.S.); Tel.: +34-93-3160854 (J.M.F.-F.); +34-93-253-2100 (M.S.)
| | - Mercedes Serrano
- U-703 Centre for Biomedical Research on Rare Diseases (CIBER-ER), Instituto de Salud Carlos III, 08002 Barcelona, Spain; (C.I.O.); (A.N.)
- Neuropediatric Department, Institut de Recerca Sant Joan de Déu, Hospital Sant Joan de Déu, 08950 Barcelona, Spain;
- Correspondence: (J.M.F.-F.); (M.S.); Tel.: +34-93-3160854 (J.M.F.-F.); +34-93-253-2100 (M.S.)
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John A, Ng-Cordell E, Hanna N, Brkic D, Baker K. The neurodevelopmental spectrum of synaptic vesicle cycling disorders. J Neurochem 2021; 157:208-228. [PMID: 32738165 DOI: 10.1111/jnc.15135] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 07/20/2020] [Accepted: 07/21/2020] [Indexed: 12/11/2022]
Abstract
In this review, we describe and discuss neurodevelopmental phenotypes arising from rare, high penetrance genomic variants which directly influence synaptic vesicle cycling (SVC disorders). Pathogenic variants in each SVC disorder gene lead to disturbance of at least one SVC subprocess, namely vesicle trafficking (e.g. KIF1A and GDI1), clustering (e.g. TRIO, NRXN1 and SYN1), docking and priming (e.g. STXBP1), fusion (e.g. SYT1 and PRRT2) or re-uptake (e.g. DNM1, AP1S2 and TBC1D24). We observe that SVC disorders share a common set of neurological symptoms (movement disorders, epilepsies), cognitive impairments (developmental delay, intellectual disabilities, cerebral visual impairment) and mental health difficulties (autism, ADHD, psychiatric symptoms). On the other hand, there is notable phenotypic variation between and within disorders, which may reflect selective disruption to SVC subprocesses, spatiotemporal and cell-specific gene expression profiles, mutation-specific effects, or modifying factors. Understanding the common cellular and systems mechanisms underlying neurodevelopmental phenotypes in SVC disorders, and the factors responsible for variation in clinical presentations and outcomes, may translate to personalized clinical management and improved quality of life for patients and families.
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Affiliation(s)
- Abinayah John
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
| | - Elise Ng-Cordell
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
| | - Nancy Hanna
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
| | - Diandra Brkic
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
| | - Kate Baker
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
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Striessnig J. Voltage-Gated Ca 2+-Channel α1-Subunit de novo Missense Mutations: Gain or Loss of Function - Implications for Potential Therapies. Front Synaptic Neurosci 2021; 13:634760. [PMID: 33746731 PMCID: PMC7966529 DOI: 10.3389/fnsyn.2021.634760] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Accepted: 02/02/2021] [Indexed: 12/12/2022] Open
Abstract
This review summarizes our current knowledge of human disease-relevant genetic variants within the family of voltage gated Ca2+ channels. Ca2+ channelopathies cover a wide spectrum of diseases including epilepsies, autism spectrum disorders, intellectual disabilities, developmental delay, cerebellar ataxias and degeneration, severe cardiac arrhythmias, sudden cardiac death, eye disease and endocrine disorders such as congential hyperinsulinism and hyperaldosteronism. A special focus will be on the rapidly increasing number of de novo missense mutations identified in the pore-forming α1-subunits with next generation sequencing studies of well-defined patient cohorts. In contrast to likely gene disrupting mutations these can not only cause a channel loss-of-function but can also induce typical functional changes permitting enhanced channel activity and Ca2+ signaling. Such gain-of-function mutations could represent therapeutic targets for mutation-specific therapy of Ca2+-channelopathies with existing or novel Ca2+-channel inhibitors. Moreover, many pathogenic mutations affect positive charges in the voltage sensors with the potential to form gating-pore currents through voltage sensors. If confirmed in functional studies, specific blockers of gating-pore currents could also be of therapeutic interest.
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Affiliation(s)
- Jörg Striessnig
- Department of Pharmacology and Toxicology, Institute of Pharmacy, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
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Jaudon F, Baldassari S, Musante I, Thalhammer A, Zara F, Cingolani LA. Targeting Alternative Splicing as a Potential Therapy for Episodic Ataxia Type 2. Biomedicines 2020; 8:E332. [PMID: 32899500 PMCID: PMC7555146 DOI: 10.3390/biomedicines8090332] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 09/01/2020] [Accepted: 09/04/2020] [Indexed: 12/26/2022] Open
Abstract
Episodic ataxia type 2 (EA2) is an autosomal dominant neurological disorder characterized by paroxysmal attacks of ataxia, vertigo, and nausea that usually last hours to days. It is caused by loss-of-function mutations in CACNA1A, the gene encoding the pore-forming α1 subunit of P/Q-type voltage-gated Ca2+ channels. Although pharmacological treatments, such as acetazolamide and 4-aminopyridine, exist for EA2, they do not reduce or control the symptoms in all patients. CACNA1A is heavily spliced and some of the identified EA2 mutations are predicted to disrupt selective isoforms of this gene. Modulating splicing of CACNA1A may therefore represent a promising new strategy to develop improved EA2 therapies. Because RNA splicing is dysregulated in many other genetic diseases, several tools, such as antisense oligonucleotides, trans-splicing, and CRISPR-based strategies, have been developed for medical purposes. Here, we review splicing-based strategies used for genetic disorders, including those for Duchenne muscular dystrophy, spinal muscular dystrophy, and frontotemporal dementia with Parkinsonism linked to chromosome 17, and discuss their potential applicability to EA2.
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Affiliation(s)
- Fanny Jaudon
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy;
| | - Simona Baldassari
- Unit of Medical Genetics, IRCCS Istituto Giannina Gaslini, 16147 Genoa, Italy; (S.B.); (I.M.); (F.Z.)
| | - Ilaria Musante
- Unit of Medical Genetics, IRCCS Istituto Giannina Gaslini, 16147 Genoa, Italy; (S.B.); (I.M.); (F.Z.)
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI), University of Genoa, 16126 Genoa, Italy
| | - Agnes Thalhammer
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia (IIT), 16132 Genoa, Italy;
- IRCCS Ospedale Policlinico San Martino, 16132 Genoa, Italy
| | - Federico Zara
- Unit of Medical Genetics, IRCCS Istituto Giannina Gaslini, 16147 Genoa, Italy; (S.B.); (I.M.); (F.Z.)
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI), University of Genoa, 16126 Genoa, Italy
| | - Lorenzo A. Cingolani
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy;
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia (IIT), 16132 Genoa, Italy;
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Ignatius E, Isohanni P, Pohjanpelto M, Lahermo P, Ojanen S, Brilhante V, Palin E, Suomalainen A, Lönnqvist T, Carroll CJ. Genetic background of ataxia in children younger than 5 years in Finland. NEUROLOGY-GENETICS 2020; 6:e444. [PMID: 32637629 PMCID: PMC7323479 DOI: 10.1212/nxg.0000000000000444] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 04/27/2020] [Indexed: 11/15/2022]
Abstract
Objective To characterize the genetic background of molecularly undefined childhood-onset ataxias in Finland. Methods This study examined a cohort of patients from 50 families with onset of an ataxia syndrome before the age of 5 years collected from a single tertiary center, drawing on the advantages offered by next generation sequencing. A genome-wide genotyping array (Illumina Infinium Global Screening Array MD-24 v.2.0) was used to search for copy number variation undetectable by exome sequencing. Results Exome sequencing led to a molecular diagnosis for 20 probands (40%). In the 23 patients examined with a genome-wide genotyping array, 2 additional diagnoses were made. A considerable proportion of probands with a molecular diagnosis had de novo pathogenic variants (45%). In addition, the study identified a de novo variant in a gene not previously linked to ataxia: MED23. Patients in the cohort had medically actionable findings. Conclusions There is a high heterogeneity of causative mutations in this cohort despite the defined age at onset, phenotypical overlap between patients, the founder effect, and genetic isolation in the Finnish population. The findings reflect the heterogeneous genetic background of ataxia seen worldwide and the substantial contribution of de novo variants underlying childhood ataxia.
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Affiliation(s)
- Erika Ignatius
- Department of Child Neurology (E.I., P.I., T.L.), Children's Hospital, University of Helsinki and Helsinki University Hospital; Research Programs Unit, Stem Cells and Metabolism, Faculty of Medicine (E.I., P.I., M.P., S.O., V.B., E.P., A.S.), Institute for Molecular Medicine Finland (FIMM) (P.L.), Neuroscience Center (A.S.), HiLife, University of Helsinki, Finland; and Genetics Research Centre (C.J.C.), Molecular and Clinical Sciences Research Institute, St. George's, University of London, United Kingdom
| | - Pirjo Isohanni
- Department of Child Neurology (E.I., P.I., T.L.), Children's Hospital, University of Helsinki and Helsinki University Hospital; Research Programs Unit, Stem Cells and Metabolism, Faculty of Medicine (E.I., P.I., M.P., S.O., V.B., E.P., A.S.), Institute for Molecular Medicine Finland (FIMM) (P.L.), Neuroscience Center (A.S.), HiLife, University of Helsinki, Finland; and Genetics Research Centre (C.J.C.), Molecular and Clinical Sciences Research Institute, St. George's, University of London, United Kingdom
| | - Max Pohjanpelto
- Department of Child Neurology (E.I., P.I., T.L.), Children's Hospital, University of Helsinki and Helsinki University Hospital; Research Programs Unit, Stem Cells and Metabolism, Faculty of Medicine (E.I., P.I., M.P., S.O., V.B., E.P., A.S.), Institute for Molecular Medicine Finland (FIMM) (P.L.), Neuroscience Center (A.S.), HiLife, University of Helsinki, Finland; and Genetics Research Centre (C.J.C.), Molecular and Clinical Sciences Research Institute, St. George's, University of London, United Kingdom
| | - Päivi Lahermo
- Department of Child Neurology (E.I., P.I., T.L.), Children's Hospital, University of Helsinki and Helsinki University Hospital; Research Programs Unit, Stem Cells and Metabolism, Faculty of Medicine (E.I., P.I., M.P., S.O., V.B., E.P., A.S.), Institute for Molecular Medicine Finland (FIMM) (P.L.), Neuroscience Center (A.S.), HiLife, University of Helsinki, Finland; and Genetics Research Centre (C.J.C.), Molecular and Clinical Sciences Research Institute, St. George's, University of London, United Kingdom
| | - Simo Ojanen
- Department of Child Neurology (E.I., P.I., T.L.), Children's Hospital, University of Helsinki and Helsinki University Hospital; Research Programs Unit, Stem Cells and Metabolism, Faculty of Medicine (E.I., P.I., M.P., S.O., V.B., E.P., A.S.), Institute for Molecular Medicine Finland (FIMM) (P.L.), Neuroscience Center (A.S.), HiLife, University of Helsinki, Finland; and Genetics Research Centre (C.J.C.), Molecular and Clinical Sciences Research Institute, St. George's, University of London, United Kingdom
| | - Virginia Brilhante
- Department of Child Neurology (E.I., P.I., T.L.), Children's Hospital, University of Helsinki and Helsinki University Hospital; Research Programs Unit, Stem Cells and Metabolism, Faculty of Medicine (E.I., P.I., M.P., S.O., V.B., E.P., A.S.), Institute for Molecular Medicine Finland (FIMM) (P.L.), Neuroscience Center (A.S.), HiLife, University of Helsinki, Finland; and Genetics Research Centre (C.J.C.), Molecular and Clinical Sciences Research Institute, St. George's, University of London, United Kingdom
| | - Eino Palin
- Department of Child Neurology (E.I., P.I., T.L.), Children's Hospital, University of Helsinki and Helsinki University Hospital; Research Programs Unit, Stem Cells and Metabolism, Faculty of Medicine (E.I., P.I., M.P., S.O., V.B., E.P., A.S.), Institute for Molecular Medicine Finland (FIMM) (P.L.), Neuroscience Center (A.S.), HiLife, University of Helsinki, Finland; and Genetics Research Centre (C.J.C.), Molecular and Clinical Sciences Research Institute, St. George's, University of London, United Kingdom
| | - Anu Suomalainen
- Department of Child Neurology (E.I., P.I., T.L.), Children's Hospital, University of Helsinki and Helsinki University Hospital; Research Programs Unit, Stem Cells and Metabolism, Faculty of Medicine (E.I., P.I., M.P., S.O., V.B., E.P., A.S.), Institute for Molecular Medicine Finland (FIMM) (P.L.), Neuroscience Center (A.S.), HiLife, University of Helsinki, Finland; and Genetics Research Centre (C.J.C.), Molecular and Clinical Sciences Research Institute, St. George's, University of London, United Kingdom
| | - Tuula Lönnqvist
- Department of Child Neurology (E.I., P.I., T.L.), Children's Hospital, University of Helsinki and Helsinki University Hospital; Research Programs Unit, Stem Cells and Metabolism, Faculty of Medicine (E.I., P.I., M.P., S.O., V.B., E.P., A.S.), Institute for Molecular Medicine Finland (FIMM) (P.L.), Neuroscience Center (A.S.), HiLife, University of Helsinki, Finland; and Genetics Research Centre (C.J.C.), Molecular and Clinical Sciences Research Institute, St. George's, University of London, United Kingdom
| | - Christopher J Carroll
- Department of Child Neurology (E.I., P.I., T.L.), Children's Hospital, University of Helsinki and Helsinki University Hospital; Research Programs Unit, Stem Cells and Metabolism, Faculty of Medicine (E.I., P.I., M.P., S.O., V.B., E.P., A.S.), Institute for Molecular Medicine Finland (FIMM) (P.L.), Neuroscience Center (A.S.), HiLife, University of Helsinki, Finland; and Genetics Research Centre (C.J.C.), Molecular and Clinical Sciences Research Institute, St. George's, University of London, United Kingdom
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9
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Stendel C, D’Adamo MC, Wiessner M, Dusl M, Cenciarini M, Belia S, Nematian-Ardestani E, Bauer P, Senderek J, Klopstock T, Pessia M. Association of A Novel Splice Site Mutation in P/Q-Type Calcium Channels with Childhood Epilepsy and Late-Onset Slowly Progressive Non-Episodic Cerebellar Ataxia. Int J Mol Sci 2020; 21:E3810. [PMID: 32471306 PMCID: PMC7312673 DOI: 10.3390/ijms21113810] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 05/19/2020] [Accepted: 05/20/2020] [Indexed: 01/20/2023] Open
Abstract
Episodic ataxia type 2 (EA2) is characterized by paroxysmal attacks of ataxia with typical onset in childhood or early adolescence. The disease is associated with mutations in the voltage-gated calcium channel alpha 1A subunit (Cav2.1) that is encoded by the CACNA1A gene. However, previously unrecognized atypical symptoms and the genetic overlap existing between EA2, spinocerebellar ataxia type 6, familial hemiplegic migraine type 1, and other neurological diseases blur the genotype/phenotype correlations, making a differential diagnosis difficult to formulate correctly and delaying early therapeutic intervention. Here we report a new clinical phenotype of a CACNA1A-associated disease characterized by absence epilepsy occurring during childhood. However, much later in life the patient displayed non-episodic, slowly progressive gait ataxia. Gene panel sequencing for hereditary ataxias led to the identification of a novel heterozygous CACNA1A mutation (c.1913 + 2T > G), altering the donor splice site of intron 14. This genetic defect was predicted to result in an in-frame deletion removing 44 amino acids from the voltage-gated calcium channel Cav2.1. An RT-PCR analysis of cDNA derived from patient skin fibroblasts confirmed the skipping of the entire exon 14. Furthermore, two-electrode voltage-clamp recordings performed from Xenopus laevis oocytes expressing a wild-type versus mutant channel showed that the genetic defect caused a complete loss of channel function. This represents the first description of distinct clinical manifestations that remarkably expand the genetic and phenotypic spectrum of CACNA1A-related diseases and should be considered for an early diagnosis and effective therapeutic intervention.
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Affiliation(s)
- Claudia Stendel
- Friedrich Baur Institute at the Department of Neurology, University Hospital, Ludwig–Maximilians–University Munich, 80336 Munich, Germany; (C.S.); (M.W.); (M.D.); (J.S.); (T.K.)
- German Center for Neurodegenerative Diseases (DZNE), 81377 Munich, Germany
| | - Maria Cristina D’Adamo
- Faculty of Medicine, Department of Physiology & Biochemistry, University of Malta, MSD 2080 Msida, Malta; (M.C.D.); (E.N.-A.)
| | - Manuela Wiessner
- Friedrich Baur Institute at the Department of Neurology, University Hospital, Ludwig–Maximilians–University Munich, 80336 Munich, Germany; (C.S.); (M.W.); (M.D.); (J.S.); (T.K.)
| | - Marina Dusl
- Friedrich Baur Institute at the Department of Neurology, University Hospital, Ludwig–Maximilians–University Munich, 80336 Munich, Germany; (C.S.); (M.W.); (M.D.); (J.S.); (T.K.)
| | - Marta Cenciarini
- Section of Physiology & Biochemistry, Department of Experimental Medicine, University of Perugia School of Medicine, 06132 Perugia, Italy;
| | - Silvia Belia
- Department of Chemistry, Biology and Biotechnology, University of Perugia, 06132 Perugia, Italy;
| | - Ehsan Nematian-Ardestani
- Faculty of Medicine, Department of Physiology & Biochemistry, University of Malta, MSD 2080 Msida, Malta; (M.C.D.); (E.N.-A.)
| | - Peter Bauer
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, 72076 Tübingen, Germany;
| | - Jan Senderek
- Friedrich Baur Institute at the Department of Neurology, University Hospital, Ludwig–Maximilians–University Munich, 80336 Munich, Germany; (C.S.); (M.W.); (M.D.); (J.S.); (T.K.)
| | - Thomas Klopstock
- Friedrich Baur Institute at the Department of Neurology, University Hospital, Ludwig–Maximilians–University Munich, 80336 Munich, Germany; (C.S.); (M.W.); (M.D.); (J.S.); (T.K.)
- German Center for Neurodegenerative Diseases (DZNE), 81377 Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany
| | - Mauro Pessia
- Faculty of Medicine, Department of Physiology & Biochemistry, University of Malta, MSD 2080 Msida, Malta; (M.C.D.); (E.N.-A.)
- Department of Physiology, United Arab Emirates University, Al Ain Po Box 17666, UAE
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10
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Rare CACNA1A mutations leading to congenital ataxia. Pflugers Arch 2020; 472:791-809. [DOI: 10.1007/s00424-020-02396-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 05/05/2020] [Accepted: 05/06/2020] [Indexed: 01/03/2023]
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11
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Tyagi S, Ribera AB, Bannister RA. Zebrafish as a Model System for the Study of Severe Ca V2.1 (α 1A) Channelopathies. Front Mol Neurosci 2020; 12:329. [PMID: 32116539 PMCID: PMC7018710 DOI: 10.3389/fnmol.2019.00329] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 12/23/2019] [Indexed: 02/02/2023] Open
Abstract
The P/Q-type CaV2.1 channel regulates neurotransmitter release at neuromuscular junctions (NMJ) and many central synapses. CACNA1A encodes the pore-containing α1A subunit of CaV2.1 channels. In humans, de novo CACNA1A mutations result in a wide spectrum of neurological, neuromuscular, and movement disorders, such as familial hemiplegic migraine type 1 (FHM1), episodic ataxia type 2 (EA2), as well as a more recently discovered class of more severe disorders, which are characterized by ataxia, hypotonia, cerebellar atrophy, and cognitive/developmental delay. Heterologous expression of CaV2.1 channels has allowed for an understanding of the consequences of CACNA1A missense mutations on channel function. In contrast, a mechanistic understanding of how specific CACNA1A mutations lead in vivo to the resultant phenotypes is lacking. In this review, we present the zebrafish as a model to both study in vivo mechanisms of CACNA1A mutations that result in synaptic and behavioral defects and to screen for effective drug therapies to combat these and other CaV2.1 channelopathies.
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Affiliation(s)
- Sidharth Tyagi
- Medical Scientist Training Program, Yale University School of Medicine, New Haven, CT, United States
| | - Angeles B Ribera
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, CO, United States
| | - Roger A Bannister
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, United States.,Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, United States
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12
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Park J, Oh HM, Park HJ, Cho AR, Lee DW, Jang JH, Jang DH. Usefulness of comprehensive targeted multigene panel sequencing for neuromuscular disorders in Korean patients. Mol Genet Genomic Med 2019; 7:e00947. [PMID: 31475473 PMCID: PMC6785438 DOI: 10.1002/mgg3.947] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 07/22/2019] [Accepted: 08/07/2019] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Multigene panel sequencing (MGPS) is the first-line option in diagnostic testing for genetically heterogeneous but clinically similar conditions, such as neuromuscular disorders (NMDs). In this study, we aimed to assess the utility of comprehensive NMD MGPS and the need for updated panels. METHODS All patients were analyzed by either of two versions of the NMD MGPS and by chromosomal microarray and karyotype testing. Four patients with negative NMD MGPS results underwent whole exome sequencing. RESULTS In total, 91 patients were enrolled, and a genetic diagnosis was made in 36 (39.6%); of these, 33 were diagnosed by the comprehensive NMD MGPS, two were confirmed by chromosomal microarray, and one was diagnosed by whole exome sequencing. For MGPS, the diagnostic yield of Version 2 (19/52; 36.5%) was a little higher than that of Version 1 (14/39; 35.9%), and one gene identified in Version 2 was not included in Version 1. A total of 36 definitive and nine possible causative variants were identified, of which 17 were novel. CONCLUSION A more comprehensive panel for NMD MGPS can improve the diagnostic efficiency in genetic testing. The rapid discovery of new disease-causing genes over recent years necessitates updates to existing gene panels.
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Affiliation(s)
- Jihye Park
- Department of Rehabilitation Medicine, Eunpyeong St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Hyun Mi Oh
- Department of Rehabilitation Medicine, National Traffic Injury Rehabilitation Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Hye Jung Park
- Department of Rehabilitation Medicine, National Traffic Injury Rehabilitation Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Ah-Ra Cho
- Department of Rehabilitation Medicine, Eunpyeong St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Dong-Woo Lee
- Department of Rehabilitation Medicine, Incheon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | | | - Dae-Hyun Jang
- Department of Rehabilitation Medicine, Incheon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
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13
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Bradley RA, Shireman J, McFalls C, Choi J, Canfield SG, Dong Y, Liu K, Lisota B, Jones JR, Petersen A, Bhattacharyya A, Palecek SP, Shusta EV, Kendziorski C, Zhang SC. Regionally specified human pluripotent stem cell-derived astrocytes exhibit different molecular signatures and functional properties. Development 2019; 146:dev.170910. [PMID: 31189664 DOI: 10.1242/dev.170910] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 06/03/2019] [Indexed: 01/10/2023]
Abstract
Astrocytes display diverse morphologies in different regions of the central nervous system. Whether astrocyte diversity is attributable to developmental processes and bears functional consequences, especially in humans, is unknown. RNA-seq of human pluripotent stem cell-derived regional astrocytes revealed distinct transcript profiles, suggesting differential functional properties. This was confirmed by differential calcium signaling as well as effects on neurite growth and blood-brain barrier formation. Distinct transcriptional profiles and functional properties of human astrocytes generated from regionally specified neural progenitors under the same conditions strongly implicate the developmental impact on astrocyte diversity. These findings provide a rationale for renewed examination of regional astrocytes and their role in the pathogenesis of psychiatric and neurological disorders.
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Affiliation(s)
- Robert A Bradley
- Department of Neuroscience, Waisman Center, University of Wisconsin - Madison, Madison, WI 53705, USA.,Cellular and Molecular Biology Program, University of Wisconsin - Madison, Madison, WI 53705, USA
| | - Jack Shireman
- Department of Neuroscience, Waisman Center, University of Wisconsin - Madison, Madison, WI 53705, USA
| | - Caya McFalls
- Department of Neuroscience, Waisman Center, University of Wisconsin - Madison, Madison, WI 53705, USA
| | - Jeea Choi
- Department of Statistics, University of Wisconsin - Madison, Madison, WI 53705, USA
| | - Scott G Canfield
- Department of Chemical and Biological Engineering, University of Wisconsin - Madison, Madison, WI 53705, USA.,Department of Cellular and Integrative Physiology, School of Medicine, Indiana University - Terre Haute, IN 47885, USA
| | - Yi Dong
- Department of Neuroscience, Waisman Center, University of Wisconsin - Madison, Madison, WI 53705, USA
| | - Katie Liu
- Department of Neuroscience, Waisman Center, University of Wisconsin - Madison, Madison, WI 53705, USA
| | - Brianne Lisota
- Department of Neuroscience, Waisman Center, University of Wisconsin - Madison, Madison, WI 53705, USA
| | - Jeffery R Jones
- Department of Neuroscience, Waisman Center, University of Wisconsin - Madison, Madison, WI 53705, USA
| | - Andrew Petersen
- Department of Neuroscience, Waisman Center, University of Wisconsin - Madison, Madison, WI 53705, USA
| | - Anita Bhattacharyya
- Department of Neuroscience, Waisman Center, University of Wisconsin - Madison, Madison, WI 53705, USA
| | - Sean P Palecek
- Department of Chemical and Biological Engineering, University of Wisconsin - Madison, Madison, WI 53705, USA
| | - Eric V Shusta
- Department of Chemical and Biological Engineering, University of Wisconsin - Madison, Madison, WI 53705, USA
| | - Christina Kendziorski
- Department of Biostatistics and Medical Informatics, University of Wisconsin - Madison, Madison, WI 53792, USA
| | - Su-Chun Zhang
- Department of Neuroscience, Waisman Center, University of Wisconsin - Madison, Madison, WI 53705, USA .,Cellular and Molecular Biology Program, University of Wisconsin - Madison, Madison, WI 53705, USA.,Department of Neuroscience, Department of Neurology, School of Medicine and Public Health, University of Wisconsin - Madison, Madison, WI 53705, USA.,Program in Neuroscience & Behavioral Disorders, Duke-NUS Medical School, Singapore 169857
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14
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15
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Autism spectrum disorders and disease modeling using stem cells. Cell Tissue Res 2017; 371:153-160. [PMID: 28918504 DOI: 10.1007/s00441-017-2685-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 08/19/2017] [Indexed: 12/13/2022]
Abstract
Autism spectrum disorders (ASD) represent a variety of disorders characterized as complex lifelong neurodevelopment disabilities, which may affect the ability of communication and socialization, including typical comportments like repetitive and stereotyped behavior. Other comorbidities are usually present, such as echolalia, hypotonia, intellectual disability and difficulties in processing figured speech. Furthermore, some ASD individuals may present certain abilities, such as eidetic memory, outstanding musical or painting talents and special mathematical skills, among others. Considering the variability of the clinical symptoms, one autistic individual can be severely affected in communication while others can speak perfectly, sometimes having a vocabulary above average in early childhood. The same variability can be seen in other clinical symptoms, thus the "spectrum" can vary from severe to mild. Induced pluripotent stem cell technology has been used to model several neurological diseases, including syndromic and non-syndromic autism. We discuss how modeling the central nervous system cells in a dish may help to reach a better understanding of ASD pathology and variability, as well as personalize their treatment.
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16
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Luo X, Rosenfeld JA, Yamamoto S, Harel T, Zuo Z, Hall M, Wierenga KJ, Pastore MT, Bartholomew D, Delgado MR, Rotenberg J, Lewis RA, Emrick L, Bacino CA, Eldomery MK, Coban Akdemir Z, Xia F, Yang Y, Lalani SR, Lotze T, Lupski JR, Lee B, Bellen HJ, Wangler MF. Clinically severe CACNA1A alleles affect synaptic function and neurodegeneration differentially. PLoS Genet 2017; 13:e1006905. [PMID: 28742085 PMCID: PMC5557584 DOI: 10.1371/journal.pgen.1006905] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 08/15/2017] [Accepted: 07/03/2017] [Indexed: 01/04/2023] Open
Abstract
Dominant mutations in CACNA1A, encoding the α-1A subunit of the neuronal P/Q type voltage-dependent Ca2+ channel, can cause diverse neurological phenotypes. Rare cases of markedly severe early onset developmental delay and congenital ataxia can be due to de novo CACNA1A missense alleles, with variants affecting the S4 transmembrane segments of the channel, some of which are reported to be loss-of-function. Exome sequencing in five individuals with severe early onset ataxia identified one novel variant (p.R1673P), in a girl with global developmental delay and progressive cerebellar atrophy, and a recurrent, de novo p.R1664Q variant, in four individuals with global developmental delay, hypotonia, and ophthalmologic abnormalities. Given the severity of these phenotypes we explored their functional impact in Drosophila. We previously generated null and partial loss-of-function alleles of cac, the homolog of CACNA1A in Drosophila. Here, we created transgenic wild type and mutant genomic rescue constructs with the two noted conserved point mutations. The p.R1673P mutant failed to rescue cac lethality, displayed a gain-of-function phenotype in electroretinograms (ERG) recorded from mutant clones, and evolved a neurodegenerative phenotype in aging flies, based on ERGs and transmission electron microscopy. In contrast, the p.R1664Q variant exhibited loss of function and failed to develop a neurodegenerative phenotype. Hence, the novel R1673P allele produces neurodegenerative phenotypes in flies and human, likely due to a toxic gain of function.
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Affiliation(s)
- Xi Luo
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States of America
| | - Jill A. Rosenfeld
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States of America
| | - Shinya Yamamoto
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, United States of America
| | - Tamar Harel
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States of America
- Baylor-Hopkins Center for Mendelian Genomics, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States of America
| | - Zhongyuan Zuo
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States of America
| | - Melissa Hall
- University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States of America
| | - Klaas J. Wierenga
- University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States of America
| | - Matthew T. Pastore
- Nationwide Children’s Hospital & The Ohio State University, Columbus, OH, United States of America
| | - Dennis Bartholomew
- Nationwide Children’s Hospital & The Ohio State University, Columbus, OH, United States of America
| | - Mauricio R. Delgado
- Department of Neurology and Neurotherapeutics, UT Southwestern Medical Center andTexas Scottish Rite Hospital, Dallas, TX, United States of America
| | | | - Richard Alan Lewis
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States of America
- Baylor-Hopkins Center for Mendelian Genomics, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States of America
- Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States of America
- Texas Children’s Hospital, Houston, TX, United States of America
| | - Lisa Emrick
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States of America
- Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States of America
| | - Carlos A. Bacino
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States of America
| | - Mohammad K. Eldomery
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States of America
- Baylor-Hopkins Center for Mendelian Genomics, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States of America
| | - Zeynep Coban Akdemir
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States of America
- Baylor-Hopkins Center for Mendelian Genomics, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States of America
| | - Fan Xia
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States of America
| | - Yaping Yang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States of America
| | - Seema R. Lalani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States of America
| | - Timothy Lotze
- Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States of America
| | - James R. Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States of America
- Baylor-Hopkins Center for Mendelian Genomics, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States of America
- Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States of America
- Texas Children’s Hospital, Houston, TX, United States of America
| | - Brendan Lee
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States of America
| | - Hugo J. Bellen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, United States of America
- Howard Hughes Medical Institute, Houston TX, United States of America
| | - Michael F. Wangler
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, United States of America
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17
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Eldomery MK, Coban-Akdemir Z, Harel T, Rosenfeld JA, Gambin T, Stray-Pedersen A, Küry S, Mercier S, Lessel D, Denecke J, Wiszniewski W, Penney S, Liu P, Bi W, Lalani SR, Schaaf CP, Wangler MF, Bacino CA, Lewis RA, Potocki L, Graham BH, Belmont JW, Scaglia F, Orange JS, Jhangiani SN, Chiang T, Doddapaneni H, Hu J, Muzny DM, Xia F, Beaudet AL, Boerwinkle E, Eng CM, Plon SE, Sutton VR, Gibbs RA, Posey JE, Yang Y, Lupski JR. Lessons learned from additional research analyses of unsolved clinical exome cases. Genome Med 2017; 9:26. [PMID: 28327206 PMCID: PMC5361813 DOI: 10.1186/s13073-017-0412-6] [Citation(s) in RCA: 162] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 02/08/2017] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Given the rarity of most single-gene Mendelian disorders, concerted efforts of data exchange between clinical and scientific communities are critical to optimize molecular diagnosis and novel disease gene discovery. METHODS We designed and implemented protocols for the study of cases for which a plausible molecular diagnosis was not achieved in a clinical genomics diagnostic laboratory (i.e. unsolved clinical exomes). Such cases were recruited to a research laboratory for further analyses, in order to potentially: (1) accelerate novel disease gene discovery; (2) increase the molecular diagnostic yield of whole exome sequencing (WES); and (3) gain insight into the genetic mechanisms of disease. Pilot project data included 74 families, consisting mostly of parent-offspring trios. Analyses performed on a research basis employed both WES from additional family members and complementary bioinformatics approaches and protocols. RESULTS Analysis of all possible modes of Mendelian inheritance, focusing on both single nucleotide variants (SNV) and copy number variant (CNV) alleles, yielded a likely contributory variant in 36% (27/74) of cases. If one includes candidate genes with variants identified within a single family, a potential contributory variant was identified in a total of ~51% (38/74) of cases enrolled in this pilot study. The molecular diagnosis was achieved in 30/63 trios (47.6%). Besides this, the analysis workflow yielded evidence for pathogenic variants in disease-associated genes in 4/6 singleton cases (66.6%), 1/1 multiplex family involving three affected siblings, and 3/4 (75%) quartet families. Both the analytical pipeline and the collaborative efforts between the diagnostic and research laboratories provided insights that allowed recent disease gene discoveries (PURA, TANGO2, EMC1, GNB5, ATAD3A, and MIPEP) and increased the number of novel genes, defined in this study as genes identified in more than one family (DHX30 and EBF3). CONCLUSION An efficient genomics pipeline in which clinical sequencing in a diagnostic laboratory is followed by the detailed reanalysis of unsolved cases in a research environment, supplemented with WES data from additional family members, and subject to adjuvant bioinformatics analyses including relaxed variant filtering parameters in informatics pipelines, can enhance the molecular diagnostic yield and provide mechanistic insights into Mendelian disorders. Implementing these approaches requires collaborative clinical molecular diagnostic and research efforts.
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Affiliation(s)
- Mohammad K. Eldomery
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030 USA
- Present Address: Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, 350 W. 11th Street, Indianapolis, IN 46202 USA
| | - Zeynep Coban-Akdemir
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030 USA
| | - Tamar Harel
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030 USA
| | - Jill A. Rosenfeld
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030 USA
| | - Tomasz Gambin
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030 USA
- Institute of Computer Science, Warsaw University of Technology, 00-665 Warsaw, Poland
| | - Asbjørg Stray-Pedersen
- Norwegian National Unit for Newborn Screening, Women and Children’s Division, Oslo University Hospital, 0424 Oslo, Norway
| | - Sébastien Küry
- CHU Nantes, Service de Génétique Médicale, 9 quai Moncousu, 44093 Nantes, CEDEX 1 France
| | - Sandra Mercier
- CHU Nantes, Service de Génétique Médicale, 9 quai Moncousu, 44093 Nantes, CEDEX 1 France
- Atlantic Gene Therapies, UMR1089, Nantes, France
| | - Davor Lessel
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Jonas Denecke
- Department of Pediatrics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Wojciech Wiszniewski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030 USA
- Texas Children’s Hospital, Houston, TX 77030 USA
| | - Samantha Penney
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030 USA
| | - Pengfei Liu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030 USA
- Baylor Genetics, Baylor College of Medicine, Houston, TX 77030 USA
| | - Weimin Bi
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030 USA
- Baylor Genetics, Baylor College of Medicine, Houston, TX 77030 USA
| | - Seema R. Lalani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030 USA
- Texas Children’s Hospital, Houston, TX 77030 USA
| | - Christian P. Schaaf
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030 USA
- Texas Children’s Hospital, Houston, TX 77030 USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, TX 77030 USA
| | - Michael F. Wangler
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030 USA
- Texas Children’s Hospital, Houston, TX 77030 USA
| | - Carlos A. Bacino
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030 USA
- Texas Children’s Hospital, Houston, TX 77030 USA
| | - Richard Alan Lewis
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030 USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, TX 77030 USA
| | - Lorraine Potocki
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030 USA
- Texas Children’s Hospital, Houston, TX 77030 USA
| | - Brett H. Graham
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030 USA
- Texas Children’s Hospital, Houston, TX 77030 USA
| | - John W. Belmont
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030 USA
- Texas Children’s Hospital, Houston, TX 77030 USA
| | - Fernando Scaglia
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030 USA
- Texas Children’s Hospital, Houston, TX 77030 USA
| | - Jordan S. Orange
- Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030 USA
- Texas Children’s Hospital Center for Human Immuno-Biology, Houston, TX USA
| | - Shalini N. Jhangiani
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030 USA
| | - Theodore Chiang
- 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
| | - Fan Xia
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030 USA
- Baylor Genetics, Baylor College of Medicine, Houston, TX 77030 USA
| | - Arthur L. Beaudet
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030 USA
- Baylor Genetics, 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, Houston, TX 77030 USA
| | - Christine M. Eng
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030 USA
- Baylor Genetics, Baylor College of Medicine, Houston, TX 77030 USA
| | - Sharon E. Plon
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030 USA
- Texas Children’s Hospital, Houston, TX 77030 USA
- Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030 USA
- Texas Children’s Cancer Center, Texas Children’s Hospital, Houston, TX 7703 USA
| | - V. Reid Sutton
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030 USA
- Texas Children’s Hospital, Houston, TX 77030 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
- Baylor-Hopkins Center for Mendelian Genomics, Baltimore, MD USA
| | - Jennifer E. Posey
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030 USA
| | - Yaping Yang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030 USA
- Baylor Genetics, Baylor College of Medicine, Houston, TX 77030 USA
| | - James R. Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030 USA
- Texas Children’s Hospital, Houston, TX 77030 USA
- Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030 USA
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030 USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Room 604B, Houston, TX 77030-3498 USA
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Ding YY, Cheng XR, Li ZQ, Wu SJ, Yang Y, Shi YH, Le GW. Effect of dietary oxidized tyrosine products on insulin secretion via the oxidative stress-induced mitochondria damage in mice pancreas. RSC Adv 2017. [DOI: 10.1039/c7ra02945d] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The findings suggested that decreased insulin secretion triggered by OTPs may be mediated by oxidative stress and mitochondrial damage in pancreatic β cells.
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Affiliation(s)
- Yin-Yi Ding
- Food Nutrition and Functional Factors Research Center
- School of Food Science and Technology
- Jiangnan University
- Wuxi
- China
| | - Xiang-Rong Cheng
- Food Nutrition and Functional Factors Research Center
- School of Food Science and Technology
- Jiangnan University
- Wuxi
- China
| | - Zhu-Qing Li
- Food Nutrition and Functional Factors Research Center
- School of Food Science and Technology
- Jiangnan University
- Wuxi
- China
| | - Sha-Ji Wu
- Food Nutrition and Functional Factors Research Center
- School of Food Science and Technology
- Jiangnan University
- Wuxi
- China
| | - Yuhui Yang
- Food Nutrition and Functional Factors Research Center
- School of Food Science and Technology
- Jiangnan University
- Wuxi
- China
| | - Yong-Hui Shi
- Food Nutrition and Functional Factors Research Center
- School of Food Science and Technology
- Jiangnan University
- Wuxi
- China
| | - Guo-Wei Le
- Food Nutrition and Functional Factors Research Center
- School of Food Science and Technology
- Jiangnan University
- Wuxi
- China
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Sun YM, Lu C, Wu ZY. Spinocerebellar ataxia: relationship between phenotype and genotype - a review. Clin Genet 2016; 90:305-14. [PMID: 27220866 DOI: 10.1111/cge.12808] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2016] [Revised: 05/16/2016] [Accepted: 05/16/2016] [Indexed: 12/12/2022]
Abstract
Spinocerebellar ataxia (SCA) comprises a large group of heterogeneous neurodegenerative disorders inherited in an autosomal dominant fashion. It is characterized by progressive cerebellar ataxia with oculomotor dysfunction, dysarthria, pyramidal signs, extrapyramidal signs, pigmentary retinopathy, peripheral neuropathy, cognitive impairment and other symptoms. It is classified according to the clinical manifestations or genetic nosology. To date, 40 SCAs have been characterized, and include SCA1-40. The pathogenic genes of 28 SCAs were identified. In recent years, with the widespread clinical use of next-generation sequencing, the genes underlying SCAs, and the mutants as well as the affected phenotypes were identified. These advances elucidated the phenotype-genotype relationship in SCAs. We reviewed the recent clinical advances, genetic features and phenotype-genotype correlations involving each SCA and its differentiation. The heterogeneity of the disease and the genetic diagnosis might be attributed to the regional distribution and clinical characteristics. Therefore, recognition of the phenotype-genotype relationship facilitates genetic testing, prognosis and monitoring of symptoms.
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Affiliation(s)
- Y-M Sun
- Department of Neurology and Institute of Neurology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - C Lu
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, the Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou, China
| | - Z-Y Wu
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, the Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, China. .,Joint Institute for Genetics and Genome Medicine between Zhejiang University and University of Toronto, Zhejiang University, Hangzhou, China.
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20
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Li C, Ching Han Chang C, Nagel J, Porebski BT, Hayashida M, Akutsu T, Song J, Buckle AM. Critical evaluation of in silico methods for prediction of coiled-coil domains in proteins. Brief Bioinform 2016; 17:270-82. [PMID: 26177815 PMCID: PMC6078162 DOI: 10.1093/bib/bbv047] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 05/29/2015] [Indexed: 12/19/2022] Open
Abstract
Coiled-coils refer to a bundle of helices coiled together like strands of a rope. It has been estimated that nearly 3% of protein-encoding regions of genes harbour coiled-coil domains (CCDs). Experimental studies have confirmed that CCDs play a fundamental role in subcellular infrastructure and controlling trafficking of eukaryotic cells. Given the importance of coiled-coils, multiple bioinformatics tools have been developed to facilitate the systematic and high-throughput prediction of CCDs in proteins. In this article, we review and compare 12 sequence-based bioinformatics approaches and tools for coiled-coil prediction. These approaches can be categorized into two classes: coiled-coil detection and coiled-coil oligomeric state prediction. We evaluated and compared these methods in terms of their input/output, algorithm, prediction performance, validation methods and software utility. All the independent testing data sets are available at http://lightning.med.monash.edu/coiledcoil/. In addition, we conducted a case study of nine human polyglutamine (PolyQ) disease-related proteins and predicted CCDs and oligomeric states using various predictors. Prediction results for CCDs were highly variable among different predictors. Only two peptides from two proteins were confirmed to be CCDs by majority voting. Both domains were predicted to form dimeric coiled-coils using oligomeric state prediction. We anticipate that this comprehensive analysis will be an insightful resource for structural biologists with limited prior experience in bioinformatics tools, and for bioinformaticians who are interested in designing novel approaches for coiled-coil and its oligomeric state prediction.
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21
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Weyhrauch DL, Ye D, Boczek NJ, Tester DJ, Gavrilova RH, Patterson MC, Wieben ED, Ackerman MJ. Whole Exome Sequencing and Heterologous Cellular Electrophysiology Studies Elucidate a Novel Loss-of-Function Mutation in the CACNA1A-Encoded Neuronal P/Q-Type Calcium Channel in a Child With Congenital Hypotonia and Developmental Delay. Pediatr Neurol 2016; 55:46-51. [PMID: 26739101 DOI: 10.1016/j.pediatrneurol.2015.10.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 10/30/2015] [Accepted: 10/31/2015] [Indexed: 01/09/2023]
Abstract
BACKGROUND A 4-year-old boy born at 37 weeks' gestation with intrauterine growth retardation presented with developmental delay with pronounced language and gross motor delay, axial hypotonia, and dynamic hypertonia of the extremities. Investigations including the Minnesota Newborn Screen, thyroid stimulating hormone/thyroxin, and inborn errors of metabolism screening were negative. Cerebral magnetic resonance imaging and spectroscopy were normal. Genetic testing was negative for coagulopathy, Smith-Lemli-Opitz, fragile X, and Prader-Willi/Angelman syndromes. Whole genome array analysis was unremarkable. METHODS Whole exome sequencing was performed through a commercial testing laboratory to elucidate the underlying etiology for the child's presentation. A de novo mutation was hypothesized. In attempt to establish pathogenicity of our candidate variant, cellular electrophysiologic functional analysis of the putative de novo mutation was performed using patch-clamp technology. RESULTS Whole exome sequencing revealed a p.P1353L variant in the CACNA1A gene, which encodes for the α1-subunit of the brain-specific P/Q-type calcium channel (CaV2.1). This presynaptic high-voltage-gated channel couples neuronal excitation to the vesicular release of neurotransmitter and is implicated in several neurologic disorders. DNA Sanger sequencing confirmed that the de novo mutation was absent in both parents and present in the child only. Electrophysiologic analysis of P1353L-CACNA1A demonstrated near complete loss of function, with a 95% reduction in peak current density. CONCLUSIONS Whole exome sequencing coupled with cellular electrophysiologic functional analysis of a de novoCACNA1A missense mutation has elucidated the probable underlying pathophysiologic mechanism responsible for the child's phenotype. Genetic testing of CACNA1A in patients with congenital hypotonia and developmental delay may be warranted.
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Affiliation(s)
- Derek L Weyhrauch
- Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, Minnesota
| | - Dan Ye
- Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Nicole J Boczek
- Department of Health Science Research, Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota
| | - David J Tester
- Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Ralitza H Gavrilova
- Department of Medical Genetics, Mayo Clinic, Rochester, Minnesota; Department of Neurology, Mayo Clinic, Rochester, Minnesota
| | - Marc C Patterson
- Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, Minnesota; Department of Medical Genetics, Mayo Clinic, Rochester, Minnesota; Department of Neurology, Mayo Clinic, Rochester, Minnesota
| | - Eric D Wieben
- Department of Medical Genetics, Mayo Clinic, Rochester, Minnesota; Departments of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota
| | - Michael J Ackerman
- Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic, Rochester, Minnesota; Department of Pediatric and Adolescent Medicine (Division of Pediatric Cardiology), Mayo Clinic, Rochester, Minnesota; Department of Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota.
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Brown SA, McCullough LD, Loew LM. Computational neurobiology is a useful tool in translational neurology: the example of ataxia. Front Neurosci 2015; 9:1. [PMID: 25653585 PMCID: PMC4300942 DOI: 10.3389/fnins.2015.00001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Accepted: 01/02/2015] [Indexed: 12/12/2022] Open
Abstract
Hereditary ataxia, or motor incoordination, affects approximately 150,000 Americans and hundreds of thousands of individuals worldwide with onset from as early as mid-childhood. Affected individuals exhibit dysarthria, dysmetria, action tremor, and diadochokinesia. In this review, we consider an array of computational studies derived from experimental observations relevant to human neuropathology. A survey of related studies illustrates the impact of integrating clinical evidence with data from mouse models and computational simulations. Results from these studies may help explain findings in mice, and after extensive laboratory study, may ultimately be translated to ataxic individuals. This inquiry lays a foundation for using computation to understand neurobiochemical and electrophysiological pathophysiology of spinocerebellar ataxias and may contribute to development of therapeutics. The interdisciplinary analysis suggests that computational neurobiology can be an important tool for translational neurology.
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Affiliation(s)
| | - Louise D McCullough
- Departments of Neurology and Neuroscience, University of Connecticut Health Center Farmington, CT, USA
| | - Leslie M Loew
- Richard D. Berlin Center for Cell Analysis and Modeling, University of Connecticut Health Center Farmington, CT, USA
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23
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Brown SA, Loew LM. Integration of modeling with experimental and clinical findings synthesizes and refines the central role of inositol 1,4,5-trisphosphate receptor 1 in spinocerebellar ataxia. Front Neurosci 2015; 8:453. [PMID: 25653583 PMCID: PMC4300941 DOI: 10.3389/fnins.2014.00453] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 12/22/2014] [Indexed: 12/22/2022] Open
Abstract
A suite of models was developed to study the role of inositol 1,4,5-trisphosphate receptor 1 (IP3R1) in spinocerebellar ataxias (SCAs). Several SCAs are linked to reduced abundance of IP3R1 or to supranormal sensitivity of the receptor to activation by its ligand inositol 1,4,5-trisphosphate (IP3). Detailed multidimensional models have been created to simulate biochemical calcium signaling and membrane electrophysiology in cerebellar Purkinje neurons. In these models, IP3R1-mediated calcium release is allowed to interact with ion channel response on the cell membrane. Experimental findings in mice and clinical observations in humans provide data input for the models. The SCA modeling suite helps interpret experimental results and provides suggestions to guide experiments. The models predict IP3R1 supersensitivity in SCA1 and compensatory mechanisms in SCA1, SCA2, and SCA3. Simulations explain the impact of calcium buffer proteins. Results show that IP3R1-mediated calcium release activates voltage-gated calcium-activated potassium channels in the plasma membrane. The SCA modeling suite unifies observations from experiments in a number of SCAs. The cadre of simulations demonstrates the central role of IP3R1.
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Affiliation(s)
| | - Leslie M Loew
- Richard D. Berlin Center for Cell Analysis and Modeling, University of Connecticut Health Center Farmington, CT, USA
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24
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Proft J, Weiss N. G protein regulation of neuronal calcium channels: back to the future. Mol Pharmacol 2014; 87:890-906. [PMID: 25549669 DOI: 10.1124/mol.114.096008] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 12/30/2014] [Indexed: 11/22/2022] Open
Abstract
Neuronal voltage-gated calcium channels have evolved as one of the most important players for calcium entry into presynaptic endings responsible for the release of neurotransmitters. In turn, and to fine-tune synaptic activity and neuronal communication, numerous neurotransmitters exert a potent negative feedback over the calcium signal provided by G protein-coupled receptors. This regulation pathway of physiologic importance is also extensively exploited for therapeutic purposes, for instance in the treatment of neuropathic pain by morphine and other μ-opioid receptor agonists. However, despite more than three decades of intensive research, important questions remain unsolved regarding the molecular and cellular mechanisms of direct G protein inhibition of voltage-gated calcium channels. In this study, we revisit this particular regulation and explore new considerations.
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Affiliation(s)
- Juliane Proft
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Norbert Weiss
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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25
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García Segarra N, Gautschi I, Mittaz-Crettol L, Kallay Zetchi C, Al-Qusairi L, Van Bemmelen MX, Maeder P, Bonafé L, Schild L, Roulet-Perez E. Congenital ataxia and hemiplegic migraine with cerebral edema associated with a novel gain of function mutation in the calcium channel CACNA1A. J Neurol Sci 2014; 342:69-78. [PMID: 24836863 DOI: 10.1016/j.jns.2014.04.027] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 03/27/2014] [Accepted: 04/21/2014] [Indexed: 10/25/2022]
Abstract
Mutations in the CACNA1A gene, encoding the α1 subunit of the voltage-gated calcium channel Ca(V)2.1 (P/Q-type), have been associated with three neurological phenotypes: familial and sporadic hemiplegic migraine type 1 (FHM1, SHM1), episodic ataxia type 2 (EA2), and spinocerebellar ataxia type 6 (SCA6). We report a child with congenital ataxia, abnormal eye movements and developmental delay who presented severe attacks of hemiplegic migraine triggered by minor head traumas and associated with hemispheric swelling and seizures. Progressive cerebellar atrophy was also observed. Remission of the attacks was obtained with acetazolamide. A de novo 3 bp deletion was found in heterozygosity causing loss of a phenylalanine residue at position 1502, in one of the critical transmembrane domains of the protein contributing to the inner part of the pore. We characterized the electrophysiology of this mutant in a Xenopus oocyte in vitro system and showed that it causes gain of function of the channel. The mutant Ca(V)2.1 activates at lower voltage threshold than the wild type. These findings provide further evidence of this molecular mechanism as causative of FHM1 and expand the phenotypic spectrum of CACNA1A mutations with a child exhibiting severe SHM1 and non-episodic ataxia of congenital onset.
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Affiliation(s)
- Nuria García Segarra
- Division of Molecular Pediatrics, Lausanne University Hospital, Lausanne, Switzerland.
| | - Ivan Gautschi
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | | | - Christine Kallay Zetchi
- Neuropediatric Unit, Department of Pediatrics, Lausanne University Hospital, Lausanne, Switzerland
| | - Lama Al-Qusairi
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | | | - Philippe Maeder
- Department of Radiology, Lausanne University Hospital, Lausanne, Switzerland
| | - Luisa Bonafé
- Division of Molecular Pediatrics, Lausanne University Hospital, Lausanne, Switzerland
| | - Laurent Schild
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Eliane Roulet-Perez
- Neuropediatric Unit, Department of Pediatrics, Lausanne University Hospital, Lausanne, Switzerland
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Bürk K, Kaiser FJ, Tennstedt S, Schöls L, Kreuz FR, Wieland T, Strom TM, Büttner T, Hollstein R, Braunholz D, Plaschke J, Gillessen-Kaesbach G, Zühlke C. A novel missense mutation in CACNA1A evaluated by in silico protein modeling is associated with non-episodic spinocerebellar ataxia with slow progression. Eur J Med Genet 2014; 57:207-11. [DOI: 10.1016/j.ejmg.2014.01.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 01/19/2014] [Indexed: 10/25/2022]
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Matilla-Dueñas A, Ashizawa T, Brice A, Magri S, McFarland KN, Pandolfo M, Pulst SM, Riess O, Rubinsztein DC, Schmidt J, Schmidt T, Scoles DR, Stevanin G, Taroni F, Underwood BR, Sánchez I. Consensus paper: pathological mechanisms underlying neurodegeneration in spinocerebellar ataxias. CEREBELLUM (LONDON, ENGLAND) 2014; 13:269-302. [PMID: 24307138 PMCID: PMC3943639 DOI: 10.1007/s12311-013-0539-y] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Intensive scientific research devoted in the recent years to understand the molecular mechanisms or neurodegeneration in spinocerebellar ataxias (SCAs) are identifying new pathways and targets providing new insights and a better understanding of the molecular pathogenesis in these diseases. In this consensus manuscript, the authors discuss their current views on the identified molecular processes causing or modulating the neurodegenerative phenotype in spinocerebellar ataxias with the common opinion of translating the new knowledge acquired into candidate targets for therapy. The following topics are discussed: transcription dysregulation, protein aggregation, autophagy, ion channels, the role of mitochondria, RNA toxicity, modulators of neurodegeneration and current therapeutic approaches. Overall point of consensus includes the common vision of neurodegeneration in SCAs as a multifactorial, progressive and reversible process, at least in early stages. Specific points of consensus include the role of the dysregulation of protein folding, transcription, bioenergetics, calcium handling and eventual cell death with apoptotic features of neurons during SCA disease progression. Unresolved questions include how the dysregulation of these pathways triggers the onset of symptoms and mediates disease progression since this understanding may allow effective treatments of SCAs within the window of reversibility to prevent early neuronal damage. Common opinions also include the need for clinical detection of early neuronal dysfunction, for more basic research to decipher the early neurodegenerative process in SCAs in order to give rise to new concepts for treatment strategies and for the translation of the results to preclinical studies and, thereafter, in clinical practice.
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Affiliation(s)
- A Matilla-Dueñas
- Health Sciences Research Institute Germans Trias i Pujol (IGTP), Ctra. de Can Ruti, Camí de les Escoles s/n, Badalona, Barcelona, Spain,
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Krey JF, Pasca SP, Shcheglovitov A, Yazawa M, Schwemberger R, Rasmusson R, Dolmetsch RE. Timothy syndrome is associated with activity-dependent dendritic retraction in rodent and human neurons. Nat Neurosci 2013; 16:201-9. [PMID: 23313911 PMCID: PMC3568452 DOI: 10.1038/nn.3307] [Citation(s) in RCA: 204] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Accepted: 12/13/2012] [Indexed: 02/07/2023]
Abstract
L-type voltage gated calcium channels have an important role in neuronal development by promoting dendritic growth and arborization. A point mutation in the gene encoding Ca(V)1.2 causes Timothy syndrome, a neurodevelopmental disorder associated with autism spectrum disorders (ASDs). We report that channels with the Timothy syndrome alteration cause activity-dependent dendrite retraction in rat and mouse neurons and in induced pluripotent stem cell (iPSC)-derived neurons from individuals with Timothy syndrome. Dendrite retraction was independent of calcium permeation through the mutant channel, was associated with ectopic activation of RhoA and was inhibited by overexpression of the channel-associated GTPase Gem. These results suggest that Ca(V)1.2 can activate RhoA signaling independently of Ca(2+) and provide insights into the cellular basis of Timothy syndrome and other ASDs.
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Affiliation(s)
- Jocelyn F. Krey
- Department of Neurobiology, Stanford University School of Medicine
| | - Sergiu P. Pasca
- Department of Neurobiology, Stanford University School of Medicine
| | | | - Masayuki Yazawa
- Department of Neurobiology, Stanford University School of Medicine
| | | | - Randall Rasmusson
- Department of Physiology and Biophysics, State University of New York at Buffalo
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Brown SA, Loew LM. Computational analysis of calcium signaling and membrane electrophysiology in cerebellar Purkinje neurons associated with ataxia. BMC SYSTEMS BIOLOGY 2012; 6:70. [PMID: 22703638 PMCID: PMC3468360 DOI: 10.1186/1752-0509-6-70] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/11/2012] [Accepted: 05/16/2012] [Indexed: 11/10/2022]
Abstract
Background Mutations in the smooth endoplasmic reticulum (sER) calcium channel Inositol Trisphosphate Receptor type 1 (IP3R1) in humans with the motor function coordination disorders Spinocerebellar Ataxia Types 15 and 16 (SCA15/16) and in a corresponding mouse model, the IP3R1delta18/delta18 mice, lead to reduced IP3R1 levels. We posit that increasing IP3R1 sensitivity to IP3 in ataxias with reduced IP3R1 could restore normal calcium response. On the other hand, in mouse models of the human polyglutamine (polyQ) ataxias, SCA2, and SCA3, the primary finding appears to be hyperactive IP3R1-mediated calcium release. It has been suggested that the polyQ SCA1 mice may also show hyperactive IP3R1. Yet, SCA1 mice show downregulated gene expression of IP3R1, Homer, metabotropic glutamate receptor (mGluR), smooth endoplasmic reticulum Ca-ATP-ase (SERCA), calbindin, parvalbumin, and other calcium signaling proteins. Results We create a computational model of pathological alterations in calcium signaling in cerebellar Purkinje neurons to investigate several forms of spinocerebellar ataxia associated with changes in the abundance, sensitivity, or activity of the calcium channel IP3R1. We find that increasing IP3R1 sensitivity to IP3 in computational models of SCA15/16 can restore normal calcium response if IP3R1 abundance is not too low. The studied range in IP3R1 levels reflects variability found in human and mouse ataxic models. Further, the required fold increases in sensitivity are within experimental ranges from experiments that use IP3R1 phosphorylation status to adjust its sensitivity to IP3. Results from our simulations of polyglutamine SCAs suggest that downregulation of some calcium signaling proteins may be partially compensatory. However, the downregulation of calcium buffer proteins observed in the SCA1 mice may contribute to pathology. Finally, our model suggests that the calcium-activated voltage-gated potassium channels may provide an important link between calcium metabolism and membrane potential in Purkinje cell function. Conclusion Thus, we have established an initial platform for computational evaluation and prediction of ataxia pathophysiology. Specifically, the model has been used to investigate SCA15/16, SCA1, SCA2, and SCA3. Results suggest that experimental studies treating mouse models of any of these ataxias with appropriately chosen peptides resembling the C-terminal of IP3R1 could adjust receptor sensitivity, and thereby modulate calcium release and normalize IP3 response. In addition, the model supports the hypothesis of IP3R1 supersensitivity in SCA1.
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Affiliation(s)
- Sherry-Ann Brown
- Richard D, Berlin Center for Cell Analysis & Modeling, University of Connecticut Health Center, Farmington, CT 06030, USA
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Jurkat-Rott K, Groome J, Lehmann-Horn F. Pathophysiological role of omega pore current in channelopathies. Front Pharmacol 2012; 3:112. [PMID: 22701429 PMCID: PMC3372090 DOI: 10.3389/fphar.2012.00112] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2012] [Accepted: 05/23/2012] [Indexed: 12/12/2022] Open
Abstract
In voltage-gated cation channels, a recurrent pattern for mutations is the neutralization of positively charged residues in the voltage-sensing S4 transmembrane segments. These mutations cause dominant ion channelopathies affecting many tissues such as brain, heart, and skeletal muscle. Recent studies suggest that the pathogenesis of associated phenotypes is not limited to alterations in the gating of the ion-conducting alpha pore. Instead, aberrant so-called omega currents, facilitated by the movement of mutated S4 segments, also appear to contribute to symptoms. Surprisingly, these omega currents conduct cations with varying ion selectivity and are activated in either a hyperpolarized or depolarized voltage range. This review gives an overview of voltage sensor channelopathies in general and focuses on pathogenesis of skeletal muscle S4 disorders for which current knowledge is most advanced.
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Riant F, Vahedi K, Tournier-Lasserve E. Atassie episodiche. Neurologia 2012. [DOI: 10.1016/s1634-7072(12)60702-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Riant F, Vahedi K, Tournier-Lasserve E. [Hereditary episodic ataxia]. Rev Neurol (Paris) 2011; 167:401-7. [PMID: 21492892 DOI: 10.1016/j.neurol.2010.10.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Revised: 08/31/2010] [Accepted: 10/13/2010] [Indexed: 12/29/2022]
Abstract
INTRODUCTION Episodic ataxia (EA) designates a group of autosomal dominant channelopathies that manifest as paroxysmal attacks of imbalance and incoordination. EA conditions are clinically and genetically heterogeneous. Seven types of EA have been reported so far but the majority of clinical cases result from two recognized entities. STATE OF ART Episodic ataxia type 1 (EA1) is characterized by brief episodes of ataxia and dysarthria, and interictal myokymia. Onset occurs during the first two decades of life. Associated epilepsy has been reported in some EA1 patients. EA1 is caused by mutations of the KCNA1 gene coding for the voltage-gated potassium channel Kv1.1. Mutation is mostly missense mutations. Acetazolamide, a carbonic-anhydrase inhibitor, may reduce the frequency and severity of the attacks in some but not all affected individuals. Episodic ataxia type 2 (EA2) is characterized by episodes lasting longer than in EA1, that manifest by ataxia, dysarthria, vertigo, and also, in most of the cases, an interictal nystagmus. Other clinical features as developmental delay or epilepsy can be present in some patients. Brain MRI shows frequently a vermian atrophy. Onset occurs typically in childhood or early adolescence, but can sometimes be in adulthood. EA2 is caused by mutations in CACNA1A, a gene coding for the neuronal voltage-gated calcium channel Cav1.1. For two-thirds of the cases, mutations lead to a stop codon. This type is most often responsive to acetazolamide that reduces the frequency and severity of attacks, but does not appear to prevent the progression of interictal symptoms. PERSPECTIVES This article summarizes current knowledge on episodic ataxia type 1 and 2 and describes briefly the other types of EA. CONCLUSION Molecular analysis of KCNA1 or CACNA1A provides a confirmation of the diagnosis of EA1 and EA2. Other types remain rare phenotypic variants. Among them, only two genes have been identified: CACNB4 in EA5 and SLC1A3 in EA6 and mutations have been found in a very few cases. No mutation can be detected in some familial cases of episodic ataxia, suggesting further heterogeneity.
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Affiliation(s)
- F Riant
- Laboratoire de génétique, groupe hospitalier Lariboisière-Fernand-Widal, AP-HP, 2, rue Ambroise-Paré, 75010 Paris, France.
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Xie G, Clapcote SJ, Nieman BJ, Tallerico T, Huang Y, Vukobradovic I, Cordes SP, Osborne LR, Rossant J, Sled JG, Henderson JT, Roder JC. Forward genetic screen of mouse reveals dominant missense mutation in the P/Q-type voltage-dependent calcium channel, CACNA1A. GENES BRAIN AND BEHAVIOR 2007; 6:717-27. [PMID: 17376154 DOI: 10.1111/j.1601-183x.2007.00302.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Dominant mutations of the P/Q-type Ca(2+) channel (CACNA1A) underlie several human neurological disorders, including episodic ataxia type 2, familial hemiplegic migraine 1 (FHM1) and spinocerebellar ataxia 6, but have not been found previously in the mouse. Here we report the first dominant ataxic mouse model of Cacna1a mutation. This Wobbly mutant allele of Cacna1a was identified in an ethylnitrosourea (ENU) mutagenesis dominant behavioral screen. Heterozygotes exhibit ataxia from 3 weeks of age and have a normal life span. Homozygotes have a righting reflex defect from postnatal day 8 and later develop severe ataxia and die prematurely. Both heterozygotes and homozygotes exhibit cerebellar atrophy with focal reduction of the molecular layer. No obvious loss of Purkinje cells or decrease in size of the granule cell layer was observed. Real-time polymerase chain reaction revealed altered expression levels of Cacna1g, Calb2 and Th in Wobbly cerebella, but Cacna1a messenger RNA and protein levels were unchanged. Positional cloning revealed that Wobbly mice have a missense mutation leading to an arginine to leucine (R1255L) substitution, resulting in neutralization of a positively charged amino acid in repeat III of voltage sensor segment S4. The dominance of the Wobbly mutation more closely resembles patterns of CACNA1A mutation in humans than previously described mouse recessive mutants (tottering, leaner, rolling Nagoya and rocker). Positive-charge neutralization in S4 has also been shown to underlie several cases of human dominant FHM1 with ataxia. The Wobbly mutant thus highlights the importance of the voltage sensor and provides a starting point to unravel the neuropathological mechanisms of this disease.
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MESH Headings
- Amino Acid Substitution/genetics
- Animals
- Ataxia/genetics
- Atrophy/genetics
- Calcium Channels, N-Type
- Calcium Channels, P-Type/genetics
- Calcium Channels, P-Type/metabolism
- Calcium Channels, Q-Type/genetics
- Calcium Channels, Q-Type/metabolism
- Cerebellum/metabolism
- Cerebellum/pathology
- Dystonia/genetics
- Female
- Gait/genetics
- Genes, Dominant/genetics
- Male
- Mice
- Mice, Inbred C3H
- Mice, Mutant Strains
- Mutation, Missense/genetics
- Polymorphism, Single Nucleotide/genetics
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Affiliation(s)
- G Xie
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Canada
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van den Maagdenberg AMJM, Haan J, Terwindt GM, Ferrari MD. Migraine: gene mutations and functional consequences. Curr Opin Neurol 2007; 20:299-305. [PMID: 17495624 DOI: 10.1097/wco.0b013e3281338d1f] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW Genetic and functional studies of mutations in familial hemiplegic migraine reveal a major role for disturbed ion transport. Gene identification in common, multifactorial migraine remains challenging. RECENT FINDINGS Several new mutations have been identified in FHM1, FHM2 and FHM3 genes. Functional consequences of familial hemiplegic migraine mutations point to an important role for cortical spreading depression in migraine pathophysiology. New genetic approaches have been tested in common migraine - novel chromosomal loci - but no gene variants have been identified. SUMMARY Identification and analysis of gene mutations in familial hemiplegic migraine revealed a major role for disturbed ion transport in this disorder. Cellular and transgenic mouse models of familial hemiplegic migraine genes suggest that increased potassium and glutamate play a role in the pathophysiology of the disorder. Despite progress, no genes have been discovered for common migraine.
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Cricchi F, Di Lorenzo C, Grieco GS, Rengo C, Cardinale A, Racaniello M, Santorelli FM, Nappi G, Pierelli F, Casali C. Early-onset progressive ataxia associated with the first CACNA1A mutation identified within the I–II loop. J Neurol Sci 2007; 254:69-71. [PMID: 17292920 DOI: 10.1016/j.jns.2007.01.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2006] [Revised: 12/27/2006] [Accepted: 01/09/2007] [Indexed: 11/20/2022]
Abstract
Familial hemiplegic migraine type 1, spinocerebellar ataxia type 6 (SCA6) and episodic ataxia type 2 (EA2) are allelic disorders associated with mutations in the CACNA1A gene, which encodes the alpha1 subunit of the P/Q-type calcium channel (Ca(V)2.1). SCA6 and EA2 share a number of clinical features, such as prominent cerebellar involvement and good response to acetazolamide therapy. However, while SCA6 develops as a late-onset, progressive ataxia, EA2 has an earlier, and episodic, onset. We report on two sisters with a heterogeneous clinical phenotype. The first developed progressive cerebellar ataxia after age 30, without noticeable episodes of vertigo or headache. A 1 year trial with acetazolamide did not produce significant results. The other reported episodes of vertigo, headache and gait imbalance since late childhood, with good response to acetazolamide, before developing moderate chronic cerebellar ataxia. Brain MRI showed cerebellar atrophy, especially in the vermis, in both patients. Direct sequencing of CACNA1A identified a heterozygous 1360G>A mutation in exon 11 resulting in the substitution of alanine for threonine at residue 454 (p.Ala454Thr). This is the first description of a change residing in the cytoplasmic I-II loop associated with a clinical phenotype.
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McKeown L, Robinson P, Jones OT. Molecular basis of inherited calcium channelopathies: role of mutations in pore-forming subunits. Acta Pharmacol Sin 2006; 27:799-812. [PMID: 16787562 DOI: 10.1111/j.1745-7254.2006.00394.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The pore-forming alpha subunits of voltage-gated calcium channels contain the essential biophysical machinery that underlies calcium influx in response to cell depolarization. In combination with requisite auxiliary subunits, these pore subunits form calcium channel complexes that are pivotal to the physiology and pharmacology of diverse cells ranging from sperm to neurons. Not surprisingly, mutations in the pore subunits generate diverse pathologies, termed channelopathies, that range from failures in excitation-contraction coupling to night blindness. Over the last decade, major insights into the mechanisms of pathogenesis have been derived from animals showing spontaneous or induced mutations. In parallel, there has been considerable growth in our understanding of the workings of voltage-gated ion channels from a structure-function, regulation and cell biology perspective. Here we document our current understanding of the mutations underlying channelopathies involving the voltage-gated calcium channel alpha subunits in humans and other species.
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Affiliation(s)
- Lynn McKeown
- Faculty of Life Sciences, the University of Manchester, Manchester, UK
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