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Zonta A, Brussino A, Dentelli P, Brusco A. A novel case of congenital spinocerebellar ataxia 5: further support for a specific phenotype associated with the p.(Arg480Trp) variant in SPTBN2. BMJ Case Rep 2020; 13:13/12/e238108. [PMID: 33318253 PMCID: PMC7737026 DOI: 10.1136/bcr-2020-238108] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
A 4-year-old girl was referred to the geneticist with a history of ataxia associated with intention tremor of the hands, strabismus and hypermetropy. Her symptoms presented about 2 years earlier with inability to walk unaided and lower limbs hypotonia. Cognitive functions were normal. Brain MRI showed a cerebellar and vermian hypoplasia with enlargement of both the cerebrospinal fluid spaces and the IV brain ventricle. Family history was unremarkable. A genetic screening using a 42-gene panel for hereditary ataxia/spastic paraparesis identified a de novo c.1438C>T - p.(Arg480Trp) missense change in the SPTBN2 gene (NM_006946.2). This variant is reported to be associated with congenital ataxia, later evolving into ataxia and intellectual disability. This case further supports the existence of a specific SPTBN2 p.(Arg480Trp)-associated phenotype, with a de novo recurrence of this variant in the heterozygous state.
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Affiliation(s)
- Andrea Zonta
- Medical Genetics Unit, Città della Salute e della Scienza University Hospital, Torino, Italy
| | | | | | - Alfredo Brusco
- Medical Genetics Unit, Città della Salute e della Scienza University Hospital, Torino, Italy,Department Medical Sciences, University of Turin, Torino, Italy
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2
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Al-Muhaizea MA, AlMutairi F, Almass R, AlHarthi S, Aldosary MS, Alsagob M, AlOdaib A, Colak D, Kaya N. A Novel Homozygous Mutation in SPTBN2 Leads to Spinocerebellar Ataxia in a Consanguineous Family: Report of a New Infantile-Onset Case and Brief Review of the Literature. THE CEREBELLUM 2019; 17:276-285. [PMID: 29196973 DOI: 10.1007/s12311-017-0893-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The objective of this study was the identification of likely genes and mutations associated with an autosomal recessive (AR) rare spinocerebellar ataxia (SCA) phenotype in two patients with infantile onset, from a consanguineous family. Using genome-wide SNP screening, autozygosity mapping, targeted Sanger sequencing and nextgen sequencing, family segregation analysis, and comprehensive neuropanel, we discovered a novel mutation in SPTBN2. Next, we utilized multiple sequence alignment of amino acids from various species as well as crystal structures provided by protein data bank (PDB# 1WYQ and 1WJM) to model the mutation site and its effect on β-III-spectrin. Finally, we used various bioinformatic classifiers to determine pathogenicity of the missense variant. A comprehensive clinical and diagnostic workup including radiological exams were performed on the patients as part of routine patient care. The homozygous missense variant (c.1572C>T; p.R414C) detected in exon 2 was fully segregated in the family and absent in a large ethnic cohort as well as publicly available data sets. Our comprehensive targeted sequencing approaches did not reveal any other likely candidate variants or mutations in both patients. The two male siblings presented with delayed motor milestones and cognitive and learning disability. Brain MRI revealed isolated cerebellar atrophy more marked in midline inferior vermis at ages of 3 and 6.5 years. Sequence alignments of the amino acids for β-III-spectrin indicated that the arginine at 414 is highly conserved among various species and located towards the end of first spectrin repeat domain. Inclusive bioinformatic analysis predicted that the variant is to be damaging and disease causing. In addition to the novel mutation, a brief literature review of the previously reported mutations as well as clinical comparison of the cases were also presented. Our study reviews the previously reported SPTBN2 mutations and cases. Moreover, the novel mutation, p.R414C, adds up to the literature for the infantile-onset form of autosomal recessive ataxia associated with SPTBN2. Previously, few SPTBN2 recessive mutations have been reported in humans. Animal models especially the β-III-/- mouse model provided insights into early coordination and gait deficit suggestive of loss-of-function. It is expected to see more recessive SPTBN2 mutations appearing in the literature during the upcoming years.
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Affiliation(s)
- Mohammad A Al-Muhaizea
- Department of Neurosciences, King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia.,College of Medicine, Al Faisal University, Riyadh, Saudi Arabia
| | - Faten AlMutairi
- Genetics Department, King Faisal Specialist Hospital and Research Center, MBC: 03, Riyadh, 11211, Saudi Arabia
| | - Rawan Almass
- Genetics Department, King Faisal Specialist Hospital and Research Center, MBC: 03, Riyadh, 11211, Saudi Arabia
| | - Safinaz AlHarthi
- Department of Neurosciences, King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia
| | - Mazhor S Aldosary
- Genetics Department, King Faisal Specialist Hospital and Research Center, MBC: 03, Riyadh, 11211, Saudi Arabia
| | - Maysoon Alsagob
- Genetics Department, King Faisal Specialist Hospital and Research Center, MBC: 03, Riyadh, 11211, Saudi Arabia
| | - Ali AlOdaib
- Genetics Department, King Faisal Specialist Hospital and Research Center, MBC: 03, Riyadh, 11211, Saudi Arabia
| | - Dilek Colak
- Department of Biostatistics and Scientific Computing, King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia
| | - Namik Kaya
- Genetics Department, King Faisal Specialist Hospital and Research Center, MBC: 03, Riyadh, 11211, Saudi Arabia.
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Ca 2+ signaling and spinocerebellar ataxia. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1865:1733-1744. [PMID: 29777722 DOI: 10.1016/j.bbamcr.2018.05.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 05/07/2018] [Accepted: 05/09/2018] [Indexed: 11/22/2022]
Abstract
Spinocerebellar ataxia (SCA) is a neural disorder, which is caused by degenerative changes in the cerebellum. SCA is primarily characterized by gait ataxia, and additional clinical features include nystagmus, dysarthria, tremors and cerebellar atrophy. Forty-four hereditary SCAs have been identified to date, along with >35 SCA-associated genes. Despite the great diversity and distinct functionalities of the SCA-related genes, accumulating evidence supports the occurrence of a common pathophysiological event among several hereditary SCAs. Altered calcium (Ca2+) homeostasis in the Purkinje cells (PCs) of the cerebellum has been proposed as a possible pathological SCA trigger. In support of this, signaling events that are initiated from or lead to aberrant Ca2+ release from the type 1 inositol 1,4,5-trisphosphate receptor (IP3R1), which is highly expressed in cerebellar PCs, seem to be closely associated with the pathogenesis of several SCA types. In this review, we summarize the current research on pathological hereditary SCA events, which involve altered Ca2+ homeostasis in PCs, through IP3R1 signaling.
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Medvedev A, Buneeva O, Gnedenko O, Ershov P, Ivanov A. Isatin, an endogenous nonpeptide biofactor: A review of its molecular targets, mechanisms of actions, and their biomedical implications. Biofactors 2018; 44:95-108. [PMID: 29336068 DOI: 10.1002/biof.1408] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 12/05/2017] [Accepted: 12/05/2017] [Indexed: 11/10/2022]
Abstract
Isatin (indole-2,3-dione) is an oxidized indole. It is widely distributed in mammalian tissues and body fluids, where isatin concentrations vary significantly from <0.1 to > 10 µM. Isatin output is increased under conditions of stress. Exogenously administered isatin is characterized by low toxicity, mutagenicity, and genotoxicity in vivo. Cytotoxic effects of isatin on various cell cultures are usually observed at concentrations exceeding 100 µM. Binding of [3 H]isatin to rat brain sections is consistent with its physiological concentrations. Proteomic analysis of mouse and rat brain isatin-binding proteins revealed about 90 individual proteins, which demonstrated significant interspecies differences (rat versus mouse). Certain evidence exist that redox state(s) and possibly other types of posttranslational modifications regulate affinity of target proteins to isatin. Recent data suggest that interacting with numerous intracellular isatin binding proteins, isatin can act as a regulator of complex protein networks in norm and pathology. Physiological concentrations of isatin in vitro inhibit monoamine oxidase B and natriuretic peptide receptor guanylate cyclase, higher (neuroprotective) concentrations (50-400 μM) cause apoptosis of various (including malignant tumor) cell lines and influence expression of certain apoptosis-related genes. Being administered in vivo, isatin exhibits various behavioral effects; it attenuates manifestations of MPTP-induced parkinsonism and tumor growth in experimental animal models. © 2017 BioFactors, 44(2):95-108, 2018.
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Affiliation(s)
- Alexei Medvedev
- Department of Proteomic Research and Mass Spectrometry, Institute of Biomedical Chemistry, Moscow, Russia
| | - Olga Buneeva
- Department of Proteomic Research and Mass Spectrometry, Institute of Biomedical Chemistry, Moscow, Russia
| | - Oksana Gnedenko
- Department of Proteomic Research and Mass Spectrometry, Institute of Biomedical Chemistry, Moscow, Russia
| | - Pavel Ershov
- Department of Proteomic Research and Mass Spectrometry, Institute of Biomedical Chemistry, Moscow, Russia
| | - Alexis Ivanov
- Department of Proteomic Research and Mass Spectrometry, Institute of Biomedical Chemistry, Moscow, Russia
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Parolin Schnekenberg R, Perkins EM, Miller JW, Davies WIL, D'Adamo MC, Pessia M, Fawcett KA, Sims D, Gillard E, Hudspith K, Skehel P, Williams J, O'Regan M, Jayawant S, Jefferson R, Hughes S, Lustenberger A, Ragoussis J, Jackson M, Tucker SJ, Németh AH. De novo point mutations in patients diagnosed with ataxic cerebral palsy. Brain 2015; 138:1817-32. [PMID: 25981959 PMCID: PMC4572487 DOI: 10.1093/brain/awv117] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 02/25/2015] [Indexed: 01/06/2023] Open
Abstract
Cerebral palsy is commonly attributed to perinatal asphyxia. However, Schnekenberg et al. describe here four individuals with ataxic cerebral palsy likely due to de novo dominant mutations associated with increased paternal age. Therefore, patients with cerebral palsy should be investigated for genetic causes before the disorder is ascribed to asphyxia. Cerebral palsy is a sporadic disorder with multiple likely aetiologies, but frequently considered to be caused by birth asphyxia. Genetic investigations are rarely performed in patients with cerebral palsy and there is little proven evidence of genetic causes. As part of a large project investigating children with ataxia, we identified four patients in our cohort with a diagnosis of ataxic cerebral palsy. They were investigated using either targeted next generation sequencing or trio-based exome sequencing and were found to have mutations in three different genes, KCNC3, ITPR1 and SPTBN2. All the mutations were de novo and associated with increased paternal age. The mutations were shown to be pathogenic using a combination of bioinformatics analysis and in vitro model systems. This work is the first to report that the ataxic subtype of cerebral palsy can be caused by de novo dominant point mutations, which explains the sporadic nature of these cases. We conclude that at least some subtypes of cerebral palsy may be caused by de novo genetic mutations and patients with a clinical diagnosis of cerebral palsy should be genetically investigated before causation is ascribed to perinatal asphyxia or other aetiologies.
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Affiliation(s)
- Ricardo Parolin Schnekenberg
- 1 Wellcome Trust Centre for Human Genetics, University of Oxford, OX3 7BN, UK 2 Universidade Positivo, School of Medicine, Rua Parigot de Souza 5300, 81280-330, Curitiba, Brazil
| | - Emma M Perkins
- 3 Centre for Integrative Physiology, Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
| | - Jack W Miller
- 4 Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK
| | - Wayne I L Davies
- 4 Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK 5 School of Animal Biology, University of Western Australia, Perth, Australia 6 Section of Physiology & Biochemistry, Department of Experimental Medicine, School of Medicine & Surgery, University of Perugia, P.le Gambuli 1, Edificio D, Piano 106132 San Sisto, Perugia, Italy
| | - Maria Cristina D'Adamo
- 6 Section of Physiology & Biochemistry, Department of Experimental Medicine, School of Medicine & Surgery, University of Perugia, P.le Gambuli 1, Edificio D, Piano 106132 San Sisto, Perugia, Italy
| | - Mauro Pessia
- 6 Section of Physiology & Biochemistry, Department of Experimental Medicine, School of Medicine & Surgery, University of Perugia, P.le Gambuli 1, Edificio D, Piano 106132 San Sisto, Perugia, Italy 7 Department of Neural and Behavioral Sciences, Pennsylvania State University College of Medicine, Hershey, PA 17033-0850, USA
| | - Katherine A Fawcett
- 8 CGAT Programme, MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford, OX1 3PT, UK
| | - David Sims
- 8 CGAT Programme, MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford, OX1 3PT, UK
| | - Elodie Gillard
- 4 Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK
| | - Karl Hudspith
- 4 Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK
| | - Paul Skehel
- 3 Centre for Integrative Physiology, Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
| | - Jonathan Williams
- 9 Oxford Medical Genetics Laboratories, Churchill Hospital, Oxford, OX3 7LJ, UK
| | - Mary O'Regan
- 10 Fraser of Allander Neurosciences Unit, Royal Hospital for Sick Children, Glasgow G3 8SJ, UK
| | - Sandeep Jayawant
- 11 Department of Paediatrics, Oxford University Hospitals NHS Trust, Oxford, OX3 9DU, UK
| | - Rosalind Jefferson
- 12 Department of Paediatrics, Royal Berkshire Foundation Trust Hospital, Reading, UK
| | - Sarah Hughes
- 12 Department of Paediatrics, Royal Berkshire Foundation Trust Hospital, Reading, UK
| | - Andrea Lustenberger
- 13 Department of Neuropaediatrics, Development and Rehabilitation, University Children's Hospital, Inselspital, Bern, Switzerland
| | - Jiannis Ragoussis
- 1 Wellcome Trust Centre for Human Genetics, University of Oxford, OX3 7BN, UK
| | - Mandy Jackson
- 3 Centre for Integrative Physiology, Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
| | - Stephen J Tucker
- 14 Clarendon Laboratory, Department of Physics, University of Oxford, OX1 3PU, UK 15 OXION Initiative in Ion Channels and Disease, University of Oxford, OX1 3PT, UK
| | - Andrea H Németh
- 4 Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK 16 Department of Clinical Genetics, Churchill Hospital, Oxford University Hospitals NHS Trust, Oxford, OX3 7LJ, UK
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Wang Y, Koh K, Miwa M, Yamashiro N, Shindo K, Takiyama Y. A Japanese SCA5 family with a novel three-nucleotide in-frame deletion mutation in the SPTBN2 gene: a clinical and genetic study. J Hum Genet 2014; 59:569-73. [PMID: 25142508 DOI: 10.1038/jhg.2014.74] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2014] [Revised: 07/23/2014] [Accepted: 07/28/2014] [Indexed: 11/09/2022]
Abstract
To date, four families with spinocerebellar ataxia type 5 (SCA5) with four distinct mutations in the spectrin, beta, nonerythrocytic 2 gene (SPTBN2) have been reported worldwide. In the present study, we identified the first Japanese family with SCA5, and analyzed this family clinically and genetically. The clinical features of the five patients in this family revealed late-onset autosomal-dominant pure cerebellar ataxia. We collected DNA samples from the majority of the family members across two generations, and exome sequencing combined with Sanger sequencing revealed a novel heterozygous three-nucleotide in-frame deletion mutation (c.2608_2610delGAG) in exon 14 of the SPTBN2 gene. This mutation cosegregated with the disease in the family and resulted in a glutamic acid deletion (p.E870del) in the sixth spectrin repeat, which is highly conserved in the SPTBN2 gene. This is the first three-nucleotide in-frame deletion mutation in this region of the beta-3 spectrin protein highly likely to be pathogenic based on exome and bioinformatic data.
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Affiliation(s)
- Ying Wang
- Department of Neurology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Yamanashi, Japan
| | - Kishin Koh
- Department of Neurology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Yamanashi, Japan
| | - Michiaki Miwa
- Department of Neurology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Yamanashi, Japan
| | - Nobuo Yamashiro
- Department of Neurology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Yamanashi, Japan
| | - Kazumasa Shindo
- Department of Neurology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Yamanashi, Japan
| | - Yoshihisa Takiyama
- Department of Neurology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Yamanashi, Japan
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7
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Abstract
Dominant spinocerebellar ataxias are a rare clinically and genetically heterogeneous group of neurodegenerative disorders. They are characterized by progressive cerebellar ataxia resulting in unsteady gait, clumsiness, dysarthria, and swallowing difficulty. The onset of symptoms is usually in the third or fourth decade of life; however, more subtle clinical manifestations can start in early childhood. Spinocerebellar ataxia type 5, a dominant spinocerebellar ataxia associated with mutations involving β-III spectrin (SPTBN2), has been described in 3 families. It typically consists of a slowly progressive spinocerebellar ataxia with onset in the third decade. The authors present the first case of infantile-onset spinocerebellar ataxia associated with a novel SPTBN2 mutation (transition C>T at nucleotide position 1438), the proband having a much more severe phenotype with global developmental delay, hypotonia, tremor, nystagmus, and facial myokymia.
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Forman OP, De Risio L, Mellersh CS. Missense mutation in CAPN1 is associated with spinocerebellar ataxia in the Parson Russell Terrier dog breed. PLoS One 2013; 8:e64627. [PMID: 23741357 PMCID: PMC3669408 DOI: 10.1371/journal.pone.0064627] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Accepted: 04/11/2013] [Indexed: 11/19/2022] Open
Abstract
Spinocerebellar ataxia (SCA) in the Parson Russell Terrier (PRT) dog breed is a disease of progressive incoordination of gait and loss of balance. Clinical signs usually become notable between 6 and 12 months of age with affected dogs presenting with symmetric spinocerebellar ataxia particularly evident in the pelvic limbs. The degree of truncal ataxia, pelvic limb hypermetria and impaired balance is progressive, particularly during the initial months of disease. A certain degree of stabilisation as well as intermittent worsening may occur. At the later stages of the disease ambulation often becomes difficult, with owners often electing to euthanise affected dogs on welfare grounds. Using a GWAS approach and target-enriched massively-parallel sequencing, a strongly associated non-synonymous SNP in the CAPN1 gene, encoding the calcium dependent cysteine protease calpain1 (mu-calpain), was identified. The SNP is a missense mutation causing a cysteine to tyrosine substitution at residue 115 of the CAPN1 protein. Cysteine 115 is a highly conserved residue and forms a key part of a catalytic triad of amino acids that are crucial to the enzymatic activity of cysteine proteases. The CAPN1 gene shows high levels of expression in the brain and nervous system and roles for the protein in both neuronal necrosis and maintenance have been suggested. Given the functional implications and high level of conservation observed across species, the CAPN1 variant represents a provocative candidate for the cause of SCA in the PRT and a novel potential cause of ataxia in humans.
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Affiliation(s)
- Oliver P Forman
- Kennel Club Genetics Centre, Animal Health Trust, Kentford, Newmarket, Suffolk, United Kingdom.
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Hekman KE, Yu GY, Brown CD, Zhu H, Du X, Gervin K, Undlien DE, Peterson A, Stevanin G, Clark HB, Pulst SM, Bird TD, White KP, Gomez CM. A conserved eEF2 coding variant in SCA26 leads to loss of translational fidelity and increased susceptibility to proteostatic insult. Hum Mol Genet 2012; 21:5472-83. [PMID: 23001565 DOI: 10.1093/hmg/dds392] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The autosomal dominant spinocerebellar ataxias (SCAs) are a genetically heterogeneous group of disorders exhibiting cerebellar atrophy and Purkinje cell degeneration whose subtypes arise from 31 distinct genetic loci. Our group previously published the locus for SCA26 on chromosome 19p13.3. In this study, we performed targeted deep sequencing of the critical interval in order to identify candidate causative variants in individuals from the SCA26 family. We identified a single variant that co-segregates with the disease phenotype that produces a single amino acid substitution in eukaryotic elongation factor 2. This substitution, P596H, sits in a domain critical for maintaining reading frame during translation. The yeast equivalent, P580H EF2, demonstrated impaired translocation, detected as an increased rate of -1 programmed ribosomal frameshift read-through in a dual-luciferase assay for observing translational recoding. This substitution also results in a greater susceptibility to proteostatic disruption, as evidenced by a more robust activation of a reporter gene driven by unfolded protein response activation upon challenge with dithiothreitol or heat shock in our yeast model system. Our results present a compelling candidate mutation and mechanism for the pathogenesis of SCA26 and further support the role of proteostatic disruption in neurodegenerative diseases.
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Affiliation(s)
- Katherine E Hekman
- Department of Neurology, Institute for Genomics and Systems Biology, University of Chicago, Chicago, IL 60637, USA
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Forman OP, De Risio L, Stewart J, Mellersh CS, Beltran E. Genome-wide mRNA sequencing of a single canine cerebellar cortical degeneration case leads to the identification of a disease associated SPTBN2 mutation. BMC Genet 2012; 13:55. [PMID: 22781464 PMCID: PMC3413603 DOI: 10.1186/1471-2156-13-55] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Accepted: 06/06/2012] [Indexed: 01/24/2023] Open
Abstract
Background Neonatal cerebellar cortical degeneration is a neurodegenerative disease described in several canine breeds including the Beagle. Affected Beagles are unable to ambulate normally from the onset of walking and the main pathological findings include Purkinje cell loss with swollen dendritic processes. Previous reports suggest an autosomal recessive mode of inheritance. The development of massively parallel sequencing techniques has presented the opportunity to investigate individual clinical cases using genome-wide sequencing approaches. We used genome-wide mRNA sequencing (mRNA-seq) of cerebellum tissue from a single Beagle with neonatal cerebellar cortical degeneration as a method of candidate gene sequencing, with the aim of identifying the causal mutation. Results A four-week old Beagle dog presented with progressive signs of cerebellar ataxia and the owner elected euthanasia. Histopathology revealed findings consistent with cerebellar cortical degeneration. Genome-wide mRNA sequencing (mRNA-seq) of RNA from cerebellum tissue was used as a method of candidate gene sequencing. After analysis of the canine orthologues of human spinocerebellar ataxia associated genes, we identified a homozygous 8 bp deletion in the β-III spectrin gene, SPTBN2, associated with spinocerebellar type 5 in humans. Genotype analysis of the sire, dam, ten clinically unaffected siblings, and an affected sibling from a previous litter, showed the mutation to fully segregate with the disorder. Previous studies have shown that β-III spectrin is critical for Purkinje cell development, and the absence of this protein can lead to cell damage through excitotoxicity, consistent with the observed Purkinje cell loss, degeneration of dendritic processes and associated neurological dysfunction in this Beagle. Conclusions An 8 bp deletion in the SPTBN2 gene encoding β-III spectrin is associated with neonatal cerebellar cortical degeneration in Beagle dogs. This study shows that mRNA-seq is a feasible method of screening candidate genes for mutations associated with rare diseases when a suitable tissue resource is available.
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Affiliation(s)
- Oliver P Forman
- Kennel Club Genetics Centre, Animal Health Trust, Kentford, Newmarket, Suffolk, CB8 7UU, UK.
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11
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Seidel K, Siswanto S, Brunt ERP, den Dunnen W, Korf HW, Rüb U. Brain pathology of spinocerebellar ataxias. Acta Neuropathol 2012; 124:1-21. [PMID: 22684686 DOI: 10.1007/s00401-012-1000-x] [Citation(s) in RCA: 278] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Revised: 05/25/2012] [Accepted: 05/25/2012] [Indexed: 12/22/2022]
Abstract
The autosomal dominant cerebellar ataxias (ADCAs) represent a heterogeneous group of neurodegenerative diseases with progressive ataxia and cerebellar degeneration. The current classification of this disease group is based on the underlying genetic defects and their typical disease courses. According to this categorization, ADCAs are divided into the spinocerebellar ataxias (SCAs) with a progressive disease course, and the episodic ataxias (EA) with episodic occurrences of ataxia. The prominent disease symptoms of the currently known and genetically defined 31 SCA types result from damage to the cerebellum and interconnected brain grays and are often accompanied by more specific extra-cerebellar symptoms. In the present review, we report the genetic and clinical background of the known SCAs and present the state of neuropathological investigations of brain tissue from SCA patients in the final disease stages. Recent findings show that the brain is commonly seriously affected in the polyglutamine SCAs (i.e. SCA1, SCA2, SCA3, SCA6, SCA7, and SCA17) and that the patterns of brain damage in these diseases overlap considerably in patients suffering from advanced disease stages. In the more rarely occurring non-polyglutamine SCAs, post-mortem neuropathological data currently are scanty and investigations have been primarily performed in vivo by means of MRI brain imaging. Only a minority of SCAs exhibit symptoms and degenerative patterns allowing for a clear and unambiguous diagnosis of the disease, e.g. retinal degeneration in SCA7, tau aggregation in SCA11, dentate calcification in SCA20, protein depositions in the Purkinje cell layer in SCA31, azoospermia in SCA32, and neurocutaneous phenotype in SCA34. The disease proteins of polyglutamine ataxias and some non-polyglutamine ataxias aggregate as cytoplasmic or intranuclear inclusions and serve as morphological markers. Although inclusions may impair axonal transport, bind transcription factors, and block protein quality control, detailed molecular and pathogenetic consequences remain to be determined.
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Affiliation(s)
- Kay Seidel
- Dr. Senckenbergisches Chronomedizinisches Institut, Goethe University, Theodor-Stern-Kai 7, 60950, Frankfurt/Main, Germany
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Abstract
The cytoskeleton forms the backbone of neuronal architecture, sustaining its form and size, subcellular compartments and cargo logistics. The synaptic cytoskeleton can be categorized in the microtubule-based core cytoskeleton and the cortical membrane skeleton. While central microtubules form the fundamental basis for the construction of elaborate neuronal processes, including axons and synapses, cortical actin filaments are generally considered to function as mediators of synapse dynamics and plasticity. More recently, the submembranous network of spectrin and ankyrin molecules has been involved in the regulation of synaptic stability and maintenance. Disruption of the synaptic cytoskeleton primarily affects the stability and maturation of synapses but also secondarily disturbs neuronal communication. Consequently, a variety of inherited diseases are accompanied by cytoskeletal malfunctions, including spastic paraplegias, spinocerebellar ataxias, and mental retardation. Since the primary reasons for many of these diseases are still unknown model organisms with a conserved repertoire of cytoskeletal elements help to understand the underlying biological mechanisms. The astonishing technical as well as genetic accessibility of synapses in Drosophila has shown that loss of the cytoskeletal architecture leads to axonal transport defects, synaptic maturation deficits, and retraction of synaptic boutons, before synaptic terminals finally detach from their target cells, suggesting that similar processes could be involved in human neuronal diseases.
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Affiliation(s)
- Bernd Goellner
- Heinrich-Heine-University Düsseldorf, Functional Cell Morphology Lab, Düsseldorf, Germany
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13
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Buneeva O, Gnedenko O, Zgoda V, Kopylov A, Glover V, Ivanov A, Medvedev A, Archakov A. Isatin-binding proteins of rat and mouse brain: Proteomic identification and optical biosensor validation. Proteomics 2009; 10:23-37. [DOI: 10.1002/pmic.200900492] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Abstract
Spectrin is a cytoskeletal protein thought to have descended from an alpha-actinin-like ancestor. It emerged during evolution of animals to promote integration of cells into tissues by assembling signalling and cell adhesion complexes, by enhancing the mechanical stability of membranes and by promoting assembly of specialized membrane domains. Spectrin functions as an (alphabeta([H]))(2) tetramer that cross-links transmembrane proteins, membrane lipids and the actin cytoskeleton, either directly or via adaptor proteins such as ankyrin and 4.1. In the present paper, I review recent findings on the origins and adaptations in this system. (i) The genome of the choanoflagellate Monosiga brevicollis encodes alpha-, beta- and beta(Heavy)-spectrin, indicating that spectrins evolved in the immediate unicellular precursors of animals. (ii) Ankyrin and 4.1 are not encoded in that genome, indicating that spectrin gained function during subsequent animal evolution. (iii) Protein 4.1 gained a spectrin-binding activity in the evolution of vertebrates. (iv) Interaction of chicken or mammal beta-spectrin with PtdInsP(2) can be regulated by differential mRNA splicing, which can eliminate the PH (pleckstrin homology) domain in betaI- or betaII-spectrins; in the case of mammalian betaII-spectrin, the alternative C-terminal region encodes a phosphorylation site that regulates interaction with alpha-spectrin. (v) In mammalian evolution, the single pre-existing alpha-spectrin gene was duplicated, and one of the resulting pair (alphaI) neo-functionalized for rapid make-and-break of tetramers. I hypothesize that the elasticity of mammalian non-nucleated erythrocytes depends on the dynamic rearrangement of spectrin dimers/tetramers under the shearing forces experienced in circulation.
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