1
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Angelini C, Goizet C, Said SA, Camu W, Depienne C, Heron B, Kol B, Guillaud-Bataille M, Pennamen P, Rooryck C, Scherer-Gagou C, Tissier L, Stevanin G, Leguern E, Banneau G. Evidence of mosaicism in SPAST variant carriers in four French families. Eur J Hum Genet 2021; 29:1158-1163. [PMID: 33958741 PMCID: PMC8298572 DOI: 10.1038/s41431-021-00847-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 02/14/2021] [Accepted: 02/24/2021] [Indexed: 11/08/2022] Open
Abstract
Hereditary spastic paraplegias (HSP) are heterogeneous disorders, with more than 70 causative genes. Variants in SPAST are the most frequent genetic etiology and are responsible for spastic paraplegia type 4 (SPG4). Age at onset can vary, even between patients from the same family, and incomplete penetrance is described. Somatic mosaicism is extremely rare with only three patients reported in the literature. We report here SPAST mosaic variants in four unrelated patients. We confirm that mosaicism in SPAST is a very rare event with only four identified cases on more than 300 patients with a SPAST variant previously described by our clinical diagnostic laboratory.
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Affiliation(s)
- Chloé Angelini
- Service de Génétique Médicale, CHU Bordeaux, Bordeaux, Bordeaux, France
- Centre de Référence Maladies Rares Neurogénétique, Service de Génétique Médicale, Bordeaux, France
| | - Cyril Goizet
- Service de Génétique Médicale, CHU Bordeaux, Bordeaux, Bordeaux, France
- Centre de Référence Maladies Rares Neurogénétique, Service de Génétique Médicale, Bordeaux, France
- INSERM U1211, laboratoire MRGM, Univ. Bordeaux, Bordeaux, France
| | - Samia Ait Said
- Sorbonne Université, AP-HP, GH Pitié-Salpêtrière, Département de génétique, Paris, France
| | - William Camu
- Centre de référence SLA, explorations neurologiques, CHU et Univ Montpellier, Montpellier, France
| | - Christel Depienne
- Sorbonne Université, AP-HP, GH Pitié-Salpêtrière, Département de génétique, Paris, France
- Sorbonne université, Institut du Cerveau, INSERM U 1127, Paris, France
- Institute of Human Genetics, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Bénédicte Heron
- Service de Neurologie Pédiatrique, Hôpital Armand Trousseau-La Roche Guyon, GHUEP, APHP, Paris, France
| | - Bophara Kol
- Sorbonne Université, AP-HP, GH Pitié-Salpêtrière, Département de génétique, Paris, France
| | | | - Perrine Pennamen
- Service de Génétique Médicale, CHU Bordeaux, Bordeaux, Bordeaux, France
- INSERM U1211, laboratoire MRGM, Univ. Bordeaux, Bordeaux, France
| | - Caroline Rooryck
- Service de Génétique Médicale, CHU Bordeaux, Bordeaux, Bordeaux, France
- INSERM U1211, laboratoire MRGM, Univ. Bordeaux, Bordeaux, France
| | - Clarisse Scherer-Gagou
- Centre National de Référence pour les Maladies Neurogénétiques de l'Adulte, Département de Neurologie, Centre Hospitalier Universitaire d'Angers, Angers, France
| | - Laurène Tissier
- Sorbonne Université, AP-HP, GH Pitié-Salpêtrière, Département de génétique, Paris, France
| | - Giovanni Stevanin
- Sorbonne Université, AP-HP, GH Pitié-Salpêtrière, Département de génétique, Paris, France
- Sorbonne université, Institut du Cerveau, INSERM U 1127, Paris, France
- Equipe de neurogénétique, Ecole Pratique des Hautes Etudes (EPHE), PSL Research University, Paris, France
| | - Eric Leguern
- Sorbonne Université, AP-HP, GH Pitié-Salpêtrière, Département de génétique, Paris, France.
- Sorbonne université, Institut du Cerveau, INSERM U 1127, Paris, France.
| | - Guillaume Banneau
- Sorbonne Université, AP-HP, GH Pitié-Salpêtrière, Département de génétique, Paris, France
- Département de Génétique Médicale, Institut Fédératif de Biologie, Hôpital Purpan, Toulouse, France
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2
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Nan H, Okamoto K, Gao L, Morishima Y, Ichinose Y, Koh K, Hashiyada M, Adachi N, Takiyama Y. A Japanese SPG4 Patient with a Confirmed De Novo Mutation of the SPAST Gene. Intern Med 2020; 59:2311-2315. [PMID: 32522921 PMCID: PMC7578612 DOI: 10.2169/internalmedicine.4599-20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Spastic paraplegia type 4 (SPG4) is caused by mutations of the SPAST gene and is the most common form of autosomal-dominantly inherited pure hereditary spastic paraplegia (HSP). We herein report a Japanese patient with SPG4 with a confirmed de novo mutation of SPAST. On exome sequencing and Sanger sequencing, we identified the heterozygous missense mutation p.R460L in the SPAST gene. This mutation was absent in the parents, and the paternity and maternity of the parents were both confirmed. The patient showed a pure SPG4 phenotype with an infantile onset. This study may expand the clinical and genetic findings for SPG4.
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Affiliation(s)
- Haitian Nan
- Department of Neurology, Graduate School of Medical Sciences, University of Yamanashi, Japan
| | - Kensho Okamoto
- Department of Neurology, Ehime Prefectural Central Hospital, Japan
| | - Lihua Gao
- Department of Neurology, Graduate School of Medical Sciences, University of Yamanashi, Japan
| | - Yuto Morishima
- Department of Neurology, Graduate School of Medical Sciences, University of Yamanashi, Japan
| | - Yuta Ichinose
- Department of Neurology, Graduate School of Medical Sciences, University of Yamanashi, Japan
| | - Kishin Koh
- Department of Neurology, Graduate School of Medical Sciences, University of Yamanashi, Japan
| | | | - Noboru Adachi
- Department of Legal Medicine, Graduate School of Medical Sciences, University of Yamanashi, Japan
| | - Yoshihisa Takiyama
- Department of Neurology, Graduate School of Medical Sciences, University of Yamanashi, Japan
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3
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Schieving JH, de Bot ST, van de Pol LA, Wolf NI, Brilstra EH, Frints SG, van Gaalen J, Misra-Isrie M, Pennings M, Verschuuren-Bemelmans CC, Kamsteeg EJ, van de Warrenburg BP, Willemsen MA. De novo SPAST mutations may cause a complex SPG4 phenotype. Brain 2020; 142:e31. [PMID: 31157359 DOI: 10.1093/brain/awz140] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Affiliation(s)
- Jolanda H Schieving
- Radboud University Medical Center, Amalia Children's Hospital and Donders Institute for Brain, Cognition and Behavior, Department of Pediatric Neurology, Nijmegen, The Netherlands
| | - Susanne T de Bot
- Leiden University Medical Center, Department of Neurology, Leiden, The Netherlands
| | - Laura A van de Pol
- Department of Child Neurology, Emma Children's Hospital, Amsterdam University Medical Centers, Vrije Universiteit Amsterdam, The Netherlands
| | - Nicole I Wolf
- Department of Child Neurology, Emma Children's Hospital, Amsterdam University Medical Centers, Vrije Universiteit Amsterdam, The Netherlands.,Amsterdam Neuroscience, Amsterdam, The Netherlands
| | - Eva H Brilstra
- University Medical Center Utrecht, Department of Medical Genetics, Utrecht, The Netherlands
| | - Suzanna G Frints
- Maastricht University Medical Center+, Department of Clinical Genetics, Maastricht, The Netherlands.,Department of Genetics and Cell Biology, GROW, School for Oncology, FHML, Maastricht University, The Netherlands
| | - Judith van Gaalen
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center and Nijmegen, The Netherlands
| | - Mala Misra-Isrie
- Amsterdam University Medical Center, Department of Clinical Genetics, Amsterdam, The Netherlands
| | - Maartje Pennings
- Radboud University Medical Center, Department of Human Genetics, Nijmegen, The Netherlands
| | | | - Erik-Jan Kamsteeg
- Radboud University Medical Center, Department of Human Genetics, Nijmegen, The Netherlands
| | - Bart P van de Warrenburg
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center and Nijmegen, The Netherlands
| | - Michèl A Willemsen
- Radboud University Medical Center, Amalia Children's Hospital and Donders Institute for Brain, Cognition and Behavior, Department of Pediatric Neurology, Nijmegen, The Netherlands
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4
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Sandate CR, Szyk A, Zehr EA, Lander GC, Roll-Mecak A. An allosteric network in spastin couples multiple activities required for microtubule severing. Nat Struct Mol Biol 2019; 26:671-678. [PMID: 31285604 PMCID: PMC6761829 DOI: 10.1038/s41594-019-0257-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 05/24/2019] [Indexed: 12/30/2022]
Abstract
The AAA+ ATPase spastin remodels microtubule arrays through severing and its mutation is the most common cause of hereditary spastic paraplegias (HSP). Polyglutamylation of the tubulin C-terminal tail recruits spastin to microtubules and modulates severing activity. Here, we present a ~3.2 Å resolution cryo-EM structure of the Drosophila melanogaster spastin hexamer with a polyglutamate peptide bound in its central pore. Two electropositive loops arranged in a double-helical staircase coordinate the substrate sidechains. The structure reveals how concurrent nucleotide and substrate binding organizes the conserved spastin pore loops into an ordered network that is allosterically coupled to oligomerization, and suggests how tubulin tail engagement activates spastin for microtubule disassembly. This allosteric coupling may apply generally in organizing AAA+ protein translocases into their active conformations. We show that this allosteric network is essential for severing and is a hotspot for HSP mutations.
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Affiliation(s)
| | - Agnieszka Szyk
- Cell Biology and Biophysics Unit, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Elena A Zehr
- Cell Biology and Biophysics Unit, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | | | - Antonina Roll-Mecak
- Cell Biology and Biophysics Unit, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA.
- Biochemistry and Biophysics Center, National Heart, Lung and Blood Institute, Bethesda, MD, USA.
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5
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Leija-Salazar M, Piette C, Proukakis C. Review: Somatic mutations in neurodegeneration. Neuropathol Appl Neurobiol 2018; 44:267-285. [PMID: 29369391 DOI: 10.1111/nan.12465] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 01/13/2018] [Indexed: 12/22/2022]
Abstract
Somatic mutations are postzygotic mutations which may lead to mosaicism, the presence of cells with genetic differences in an organism. Their role in cancer is well established, but detailed investigation in health and other diseases has only been recently possible. This has been empowered by the improvements of sequencing techniques, including single-cell sequencing, which can still be error-prone but is rapidly improving. Mosaicism appears relatively common in the human body, including the normal brain, probably arising in early development, but also potentially during ageing. In this review, we first discuss theoretical considerations and current evidence relevant to somatic mutations in the brain. We present a framework to explain how they may be integrated with current views on neurodegeneration, focusing mainly on sporadic late-onset neurodegenerative diseases (Parkinson's disease, Alzheimer's disease and amyotrophic lateral sclerosis). We review the relevant studies so far, with the first evidence emerging in Alzheimer's in particular. We also discuss the role of mosaicism in inherited neurodegenerative disorders, particularly somatic instability of tandem repeats. We summarize existing views and data to present a model whereby the time of origin and spatial distribution of relevant somatic mutations, combined with any additional risk factors, may partly determine the development and onset age of sporadic neurodegenerative diseases.
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Affiliation(s)
- M Leija-Salazar
- Department of Clinical Neuroscience, University College London Institute of Neurology, London, UK
| | - C Piette
- Department of Clinical Neuroscience, University College London Institute of Neurology, London, UK
| | - C Proukakis
- Department of Clinical Neuroscience, University College London Institute of Neurology, London, UK
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6
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Matthews AM, Tarailo-Graovac M, Price EM, Blydt-Hansen I, Ghani A, Drögemöller BI, Robinson WP, Ross CJ, Wasserman WW, Siden H, van Karnebeek CD. A de novo mosaic mutation in SPAST with two novel alternative alleles and chromosomal copy number variant in a boy with spastic paraplegia and autism spectrum disorder. Eur J Med Genet 2017; 60:548-552. [PMID: 28778789 DOI: 10.1016/j.ejmg.2017.07.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 07/30/2017] [Accepted: 07/30/2017] [Indexed: 11/30/2022]
Abstract
Here we report a 12 year old male with an extreme presentation of spastic paraplegia along with autism and dysmorphisms. Whole exome sequencing identified a predicted pathogenic pair of missense variants in SPAST at the same chromosomal location, each with a different alternative allele, while a chromosome microarray identified a 1.73 Mb paternally inherited copy gain of 1q21.1q21.2 resulting in a blended phenotype of both Spastic paraplegia 4 and 1q21.1 microduplication syndrome. We believe that the extreme phenotype observed is likely caused by the presence of cells which contain only mutant SPAST, but that the viability of the patient is possible due mosaicism of mutant alleles observed in different proportions across tissues.
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Affiliation(s)
- A M Matthews
- Centre for Molecular Medicine and Therapeutics, Vancouver, BC, Canada; Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada; BC Children's Hospital Research Institute, Vancouver, BC, Canada
| | - M Tarailo-Graovac
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada; BC Children's Hospital Research Institute, Vancouver, BC, Canada
| | - E M Price
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada; BC Children's Hospital Research Institute, Vancouver, BC, Canada
| | - I Blydt-Hansen
- BC Children's Hospital Research Institute, Vancouver, BC, Canada; Department of Pediatrics, BC Children's Hospital, Vancouver, BC, Canada
| | - A Ghani
- Department of Pediatrics, BC Children's Hospital, Vancouver, BC, Canada
| | - B I Drögemöller
- Centre for Molecular Medicine and Therapeutics, Vancouver, BC, Canada; BC Children's Hospital Research Institute, Vancouver, BC, Canada; Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC, Canada
| | - W P Robinson
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada; BC Children's Hospital Research Institute, Vancouver, BC, Canada
| | - C J Ross
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada; BC Children's Hospital Research Institute, Vancouver, BC, Canada; Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC, Canada
| | - W W Wasserman
- Centre for Molecular Medicine and Therapeutics, Vancouver, BC, Canada; Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada; BC Children's Hospital Research Institute, Vancouver, BC, Canada
| | - H Siden
- BC Children's Hospital Research Institute, Vancouver, BC, Canada; Department of Pediatrics, BC Children's Hospital, Vancouver, BC, Canada; Canuck Place Children's Hospice, Vancouver, BC, Canada
| | - C D van Karnebeek
- Centre for Molecular Medicine and Therapeutics, Vancouver, BC, Canada; BC Children's Hospital Research Institute, Vancouver, BC, Canada; Department of Pediatrics, BC Children's Hospital, Vancouver, BC, Canada; Departments of Pediatrics and Clinical Genetics, Academic Medical Centre, University of Amsterdam, The Netherlands.
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7
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Polymeris AA, Tessa A, Anagnostopoulou K, Rubegni A, Galatolo D, Dinopoulos A, Gika AD, Youroukos S, Skouteli E, Santorelli FM, Pons R. A series of Greek children with pure hereditary spastic paraplegia: clinical features and genetic findings. J Neurol 2016; 263:1604-11. [DOI: 10.1007/s00415-016-8179-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Revised: 05/08/2016] [Accepted: 05/17/2016] [Indexed: 11/29/2022]
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8
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Yu W, You X, Wang D, Dong K, Su J, Li C, Liu J, Zhang Q, You F, Wang X, Huang J, Qiao B, Duan W. Microarray analysis unmasked two siblings with pure hereditary spastic paraplegia shared a run of homozygosity region on chromosome 3q28-q29. J Neurol Sci 2015; 359:351-5. [PMID: 26671141 DOI: 10.1016/j.jns.2015.10.057] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Revised: 10/21/2015] [Accepted: 10/27/2015] [Indexed: 11/29/2022]
Abstract
Hereditary spastic paraplegia (HSP) is a clinical and genetic heterogeneity group of neurodegenerative disorders which is characterized by progressive weakness and spasticity of the lower limbs. More than 70 genetic types of HSP have been described so far. Here we describe a Chinese non-consanguineous family with two affected siblings manifesting early-onset autosomal recessive HSP in pure forms. To identify genotype and characterize phenotype, CytoScan HD array analysis was performed on the two siblings. A run of homozygosity (ROH) shared by the two patients was detected on chromosome 3q28-q29. The ROH region, about 7.7Mb on the chromosome 3:190172058-197851260 partially overlapped with the ROH region of SPG14 previously reported. Subsequently, microsatellite analysis confirmed this ROH and whole-exome sequencing was carried out while no causative mutations were found in the exons of known HSP genes and 68 candidate genes in that region. In conclusion, our data suggest the ROH in this region may play a pivotal role in SPG14 pathogenesis. This is the first clinical description of a pure form spastic paraplegia in a non-consanguineous family associated with the SPG14 locus.
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Affiliation(s)
- Wenqian Yu
- Institute of Cardiovascular Disease, General Hospital of Jinan Military Region, 8 Lashan Road, Jinan 250022, China
| | - Xiangdong You
- Division of Quality Management, Shandong Center for Disease Control and Prevention, 16992 Jingshi Road, Jinan 250014, China
| | - Dong Wang
- Institute of Cardiovascular Disease, General Hospital of Jinan Military Region, 8 Lashan Road, Jinan 250022, China
| | - Kai Dong
- Institute of Cardiovascular Disease, General Hospital of Jinan Military Region, 8 Lashan Road, Jinan 250022, China
| | - Jing Su
- Department of Neurology, General Hospital of Jinan Military Region, 25 Shifan Road, Jinan 250031, China
| | - Chuanfen Li
- Department of Neurology, General Hospital of Jinan Military Region, 25 Shifan Road, Jinan 250031, China
| | - Jinxiu Liu
- Institute of Cardiovascular Disease, General Hospital of Jinan Military Region, 8 Lashan Road, Jinan 250022, China
| | - Qianqian Zhang
- Institute of Cardiovascular Disease, General Hospital of Jinan Military Region, 8 Lashan Road, Jinan 250022, China
| | - Feng You
- Institute of Cardiovascular Disease, General Hospital of Jinan Military Region, 8 Lashan Road, Jinan 250022, China
| | - Xiangrong Wang
- Institute of Cardiovascular Disease, General Hospital of Jinan Military Region, 8 Lashan Road, Jinan 250022, China
| | - Jing Huang
- Institute of Cardiovascular Disease, General Hospital of Jinan Military Region, 8 Lashan Road, Jinan 250022, China
| | - Bin Qiao
- Institute of Cardiovascular Disease, General Hospital of Jinan Military Region, 8 Lashan Road, Jinan 250022, China.
| | - Wenyuan Duan
- Institute of Cardiovascular Disease, General Hospital of Jinan Military Region, 8 Lashan Road, Jinan 250022, China.
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9
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Yang Y, Liu W, Fang Z, Shi J, Che F, He C, Yao L, Wang E, Wu Y. A Newly Identified Missense Mutation in FARS2 Causes Autosomal-Recessive Spastic Paraplegia. Hum Mutat 2015; 37:165-9. [PMID: 26553276 DOI: 10.1002/humu.22930] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 11/03/2015] [Indexed: 02/05/2023]
Abstract
Hereditary spastic paraplegia (HSP) is a clinically and genetically heterogeneous group of neurodegenerative disorders characterized by spasticity of the lower limbs due to pyramidal tract dysfunction. Here, we report that a missense homozygous mutation c.424G>T (p.D142Y) in the FARS2 gene, which encodes a mitochondrial phenylalanyl tRNA synthetase (mtPheRS), causes HSP in a Chinese consanguineous family by using combination of homozygous mapping and whole-exome sequencing. Immunohistochemical experiments were performed showing that the FARS2 protein was highly expressed in the Purkinje cells of rat cerebellum. The aminoacylation activity of mtPheRS was severely disrupted by the p.D142Y substitution in vitro not only in the first aminoacylation step but also in the last transfer step. Taken together, our results indicate that a missense mutation in FARS2 contributes to HSP, which has the clinical significance of the regulation of tRNA synthetases in human neurodegenerative diseases.
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Affiliation(s)
- Ying Yang
- Department of Biochemistry and Molecular Biology, Xi'an, Shaanxi, 710032, China.,Center for DNA Typing, Xi'an, Shaanxi, 710032, China
| | - Wei Liu
- Department of physiotherapy, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, 710032, China
| | - Zhipeng Fang
- Center for RNA Research, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences, Shanghai, 710031, China
| | - Juan Shi
- Department of Anatomy, Histology and Embryology & K.K. Leung Brain Research Centre, Preclinical School of Medicine, Fourth Military Medical University, Xi'an, Shaanxi, 200032, China
| | - Fengyu Che
- Center for DNA Typing, Xi'an, Shaanxi, 710032, China
| | - Chunxia He
- Department of Biochemistry and Molecular Biology, Xi'an, Shaanxi, 710032, China.,Center for DNA Typing, Xi'an, Shaanxi, 710032, China
| | - Libo Yao
- Department of Biochemistry and Molecular Biology, Xi'an, Shaanxi, 710032, China
| | - Enduo Wang
- Center for RNA Research, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences, Shanghai, 710031, China
| | - Yuanming Wu
- Department of Biochemistry and Molecular Biology, Xi'an, Shaanxi, 710032, China.,Center for DNA Typing, Xi'an, Shaanxi, 710032, China
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10
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Aguirre-Rodríguez FJ, Lucenilla MIR, Alvarez-Cubero M, Mata C, Entrala-Bernal C, Fernandez-Rosado F. Novel FA2H mutation in a girl with familial spastic paraplegia. J Neurol Sci 2015; 357:332-4. [DOI: 10.1016/j.jns.2015.07.042] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 07/27/2015] [Accepted: 07/28/2015] [Indexed: 11/26/2022]
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11
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Solowska JM, Baas PW. Hereditary spastic paraplegia SPG4: what is known and not known about the disease. Brain 2015; 138:2471-84. [PMID: 26094131 DOI: 10.1093/brain/awv178] [Citation(s) in RCA: 111] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 05/02/2015] [Indexed: 01/11/2023] Open
Abstract
Mutations in more than 70 distinct loci and more than 50 mutated gene products have been identified in patients with hereditary spastic paraplegias, a diverse group of neurological disorders characterized predominantly, but not exclusively, by progressive lower limb spasticity and weakness resulting from distal degeneration of corticospinal tract axons. Mutations in the SPAST (previously known as SPG4) gene that encodes the microtubule-severing protein called spastin, are the most common cause of the disease. The aetiology of the disease is poorly understood, but partial loss of microtubule-severing activity resulting from inactivating mutations in one SPAST allele is the most postulated explanation. Microtubule severing is important for regulating various aspects of the microtubule array, including microtubule number, length, and mobility. In addition, higher numbers of dynamic plus-ends of microtubules, resulting from microtubule-severing events, may play a role in endosomal tubulation and fission. Even so, there is growing evidence that decreased severing of microtubules does not fully explain HSP-SPG4. The presence of two translation initiation codons in SPAST allows synthesis of two spastin isoforms: a full-length isoform called M1 and a slightly shorter isoform called M87. M87 is more abundant in both neuronal and non-neuronal tissues. Studies on rodents suggest that M1 is only readily detected in adult spinal cord, which is where nerve degeneration mainly occurs in humans with HSP-SPG4. M1, due to its hydrophobic N-terminal domain not shared by M87, may insert into endoplasmic reticulum membrane, and together with reticulons, atlastin and REEP1, may play a role in the morphogenesis of this organelle. Some mutated spastins may act in dominant-negative fashion to lower microtubule-severing activity, but others have detrimental effects on neurons without further lowering microtubule severing. The observed adverse effects on microtubule dynamics, axonal transport, endoplasmic reticulum, and endosomal trafficking are likely caused not only by diminished severing of microtubules, but also by neurotoxicity of mutant spastin proteins, chiefly M1. Some large deletions in SPAST might also affect the function of adjacent genes, further complicating the aetiology of the disease.
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Affiliation(s)
- Joanna M Solowska
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA 19129, USA
| | - Peter W Baas
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA 19129, USA
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