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Ferese R, Scala S, Suppa A, Campopiano R, Asci F, Zampogna A, Chiaravalloti MA, Griguoli A, Storto M, Pardo AD, Giardina E, Zampatti S, Fornai F, Novelli G, Fanelli M, Zecca C, Logroscino G, Centonze D, Gambardella S. Cohort analysis of novel SPAST variants in SPG4 patients and implementation of in vitro and in vivo studies to identify the pathogenic mechanism caused by splicing mutations. Front Neurol 2023; 14:1296924. [PMID: 38145127 PMCID: PMC10748595 DOI: 10.3389/fneur.2023.1296924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 11/14/2023] [Indexed: 12/26/2023] Open
Abstract
Introduction Pure hereditary spastic paraplegia (SPG) type 4 (SPG4) is caused by mutations of SPAST gene. This study aimed to analyze SPAST variants in SPG4 patients to highlight the occurrence of splicing mutations and combine functional studies to assess the relevance of these variants in the molecular mechanisms of the disease. Methods We performed an NGS panel in 105 patients, in silico analysis for splicing mutations, and in vitro minigene assay. Results and discussion The NGS panel was applied to screen 105 patients carrying a clinical phenotype corresponding to upper motor neuron syndrome (UMNS), selectively affecting motor control of lower limbs. Pathogenic mutations in SPAST were identified in 12 patients (11.42%), 5 missense, 3 frameshift, and 4 splicing variants. Then, we focused on the patients carrying splicing variants using a combined approach of in silico and in vitro analysis through minigene assay and RNA, if available. For two splicing variants (i.e., c.1245+1G>A and c.1414-2A>T), functional assays confirm the types of molecular alterations suggested by the in silico analysis (loss of exon 9 and exon 12). In contrast, the splicing variant c.1005-1delG differed from what was predicted (skipping exon 7), and the functional study indicates the loss of frame and formation of a premature stop codon. The present study evidenced the high splice variants in SPG4 patients and indicated the relevance of functional assays added to in silico analysis to decipher the pathogenic mechanism.
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Affiliation(s)
| | | | - Antonio Suppa
- IRCCS Neuromed, Pozzilli, Italy
- Department of Human Neurosciences, Sapienza University of Rome, Rome, Italy
| | | | | | | | | | | | | | | | - Emiliano Giardina
- Genomic Medicine Laboratory, IRCCS Fondazione Santa Lucia, Rome, Italy
| | - Stefania Zampatti
- Genomic Medicine Laboratory, IRCCS Fondazione Santa Lucia, Rome, Italy
| | - Francesco Fornai
- IRCCS Neuromed, Pozzilli, Italy
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Giuseppe Novelli
- IRCCS Neuromed, Pozzilli, Italy
- Department of Biomedicine and Prevention, University of Rome “Tor Vergata”, Rome, Italy
| | - Mirco Fanelli
- Department of Biomolecular Sciences, University of Urbino “Carlo Bo”, Urbino, Italy
| | - Chiara Zecca
- Center for Neurodegenerative Diseases and the Aging Brain, Department of Clinical Research in Neurology of the University of Bari “Aldo Moro” at “Pia Fondazione Card G. Panico” Hospital Tricase, Lecce, Italy
| | - Giancarlo Logroscino
- Center for Neurodegenerative Diseases and the Aging Brain, Department of Clinical Research in Neurology of the University of Bari “Aldo Moro” at “Pia Fondazione Card G. Panico” Hospital Tricase, Lecce, Italy
| | - Diego Centonze
- IRCCS Neuromed, Pozzilli, Italy
- Department of Systems Medicine, Tor Vergata University, Rome, Italy
| | - Stefano Gambardella
- IRCCS Neuromed, Pozzilli, Italy
- Department of Biomolecular Sciences, University of Urbino “Carlo Bo”, Urbino, Italy
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Erfanian Omidvar M, Torkamandi S, Rezaei S, Alipoor B, Omrani MD, Darvish H, Ghaedi H. Genotype-phenotype associations in hereditary spastic paraplegia: a systematic review and meta-analysis on 13,570 patients. J Neurol 2019; 268:2065-2082. [PMID: 31745725 DOI: 10.1007/s00415-019-09633-1] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 11/07/2019] [Accepted: 11/09/2019] [Indexed: 12/13/2022]
Abstract
AIMS The hereditary spastic paraplegias (HSPs) are a heterogeneous group of inherited neurodegenerative disorders. Although, several genotype-phenotype studies have carried out on HSPs, the association between genotypes and clinical phenotypes remain incomplete since most studies are small in size or restricted to a few genes. Accordingly, this study provides the systematic meta-analysis of genotype-phenotype associations in HSP. METHODS AND RESULTS We retrieved literature on genotype-phenotype associations in patients with HSP and mutated SPAST, REEP1, ATL1, SPG11, SPG15, SPG7, SPG35, SPG54, SPG5. In total, 147 studies with 13,570 HSP patients were included in our meta-analysis. The frequency of mutations in SPAST (25%) was higher than REEP1 (3%), as well as ATL1 (5%) in AD-HSP patients. As for AR-HSP patients, the rates of mutations in SPG11 (18%), SPG15 (7%) and SPG7 (13%) were higher than SPG5 (5%), as well as SPG35 (8%) and SPG54 (7%). The mean age of AD-HSP onset for ATL1 mutation-positive patients was earlier than patients with SPAST, REEP1 mutations. Also, the tendency toward younger age at AR-HSP onset for SPG35 was higher than other mutated genes. It is noteworthy that the mean age at HSP onset ranged from infancy to adulthood. As for the gender distribution, the male proportion in SPG7-HSP (90%) and REEP1-HSP (78%) was markedly high. The frequency of symptoms was varied among patients with different mutated genes. The rates of LL weakness, superficial sensory abnormalities, neuropathy, and deep sensory impairment were noticeably high in REEP1 mutations carriers. Also, in AR-HSP patients with SPG11 mutations, the presentation of symptoms including pes cavus, Neuropathy, and UL spasticity was higher. CONCLUSION Our comprehensive genotype-phenotype assessment of available data displays that the mean age at disease onset and particular sub-phenotypes are associated with specific mutated genes which might be beneficial for a diagnostic procedure and differentiation of the specific mutated genes phenotype among diverse forms of HSP.
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Affiliation(s)
- Maryam Erfanian Omidvar
- Department of Medical Laboratory Technology, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Shahram Torkamandi
- Department of Medical Genetics and Immunology, Faculty of Medicine, Urmia University of Medical Sciences, Urmia, Iran
| | - Somaye Rezaei
- Department of Neurology, Imam Khomeini Hospital, Urmia University of Medical Sciences, Urmia, Iran
| | - Behnam Alipoor
- Department of Laboratory Sciences, Faculty of Parmedicine, Yasuj University of Medical Sciences, Yasuj, Iran
| | - Mir Davood Omrani
- Department of Medical Genetics, School of Medicine, Shahid Beheshti University of Medical Sciences, Velenjak St., Shahid Chamran Highway, Tehran, IR, Iran
| | - Hossein Darvish
- Department of Medical Genetics, School of Medicine, Semnan University of Medical Sciences, Semnan, Iran
| | - Hamid Ghaedi
- Department of Medical Genetics, School of Medicine, Shahid Beheshti University of Medical Sciences, Velenjak St., Shahid Chamran Highway, Tehran, IR, Iran.
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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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Li T, Tu L, Zhang Q, Gu R, Wang Q, Wang B, Yao H, Qu X, Wang W, Tian J. SPG3A gene polymorphisms in hereditary spastic paraplegia. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2017; 10:9760-9764. [PMID: 31966859 PMCID: PMC6965986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 07/14/2017] [Indexed: 06/10/2023]
Abstract
OBJECTIVE This study aimed to analyze the hereditary spastic paraplegia (HSP)/spastic paraplegia 3A (SPG3A) genomic structure as well as the polymorphisms in SPG3G genomic structure by comparing with the normal subjects. METHODS A total of 66 sporadic cases with HSP were collected from April 2014 to September 2016. Genomic DNA extraction was performed, and all coding exons and junction region in the SPG3A gene were sequenced. Genetic mutations were identified and DNA sequence alignment was performed against 80 normal subjects without blood relationship. The polymorphism in SPG3A gene was analyzed. RESULTS The coding sequence of the SPG3A gene consisted of 14 exons and two polymorphisms were detected at exons 2 and 3 compared with the normal subjects; one polymorphism was detected at exons 3, 4 and 6, respectively. CONCLUSION The two coding exons in the SPG3A gene in normal subjects were polymorphic and highly conservative. The intron consisted of 3 polymorphic coding sequences. Understanding the polymorphism and genetic mutations in the SPG3A gene will contribute to the diagnosis and treatment of HSP.
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Affiliation(s)
- Tian Li
- Zunyi Medical CollegeGuizhou, China
- Department of Emergency, Guizhou Provincial People’s HospitalGuizhou, China
| | - Li Tu
- Department of Emergency, Guizhou Provincial People’s HospitalGuizhou, China
- Department of Emergency, The Affiliated Hospital of Guizhou Medical UniversityGuizhou, China
| | - Qian Zhang
- Department of Emergency, Guizhou Provincial People’s HospitalGuizhou, China
| | - Ran Gu
- Department of Neurology, Guizhou Provincial People’s HospitalGuizhou, China
| | - Qian Wang
- Department of Neurology, Guizhou Provincial People’s HospitalGuizhou, China
| | - Bingjin Wang
- Department of Emergency, Guizhou Provincial People’s HospitalGuizhou, China
| | - Huan Yao
- Department of Emergency, Guizhou Provincial People’s HospitalGuizhou, China
| | - Xiang Qu
- Department of Emergency, Guizhou Provincial People’s HospitalGuizhou, China
| | - Wenqin Wang
- Department of Emergency, Guizhou Provincial People’s HospitalGuizhou, China
| | - Jinyong Tian
- Department of Emergency, Guizhou Provincial People’s HospitalGuizhou, China
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Kim TH, Lee JH, Park YE, Shin JH, Nam TS, Kim HS, Jang HJ, Semenov A, Kim SJ, Kim DS. Mutation analysis of SPAST, ATL1, and REEP1 in Korean Patients with Hereditary Spastic Paraplegia. J Clin Neurol 2014; 10:257-61. [PMID: 25045380 PMCID: PMC4101104 DOI: 10.3988/jcn.2014.10.3.257] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Revised: 12/16/2013] [Accepted: 12/17/2013] [Indexed: 12/19/2022] Open
Abstract
Background and Purpose Hereditary spastic paraplegia (HSP) is a genetically heterogeneous group of neurodegenerative disorders that are characterized by progressive spasticity and weakness of the lower limbs. Mutations in the spastin gene (SPAST) are the most common causes of HSP, accounting for 40-67% of autosomal dominant HSP (AD-HSP) and 12-18% of sporadic cases. Mutations in the atlastin-1 gene (ATL1) and receptor expression-enhancing protein 1 gene (REEP1) are the second and third most common causes of AD-HSP, respectively. Methods Direct sequence analysis was used to screen mutations in SPAST, ATL1, and REEP1 in 27 unrelated Korean patients with pure and complicated HSP. Multiplex ligation-dependent probe amplification was also performed to detect copy-number variations of the three genes. Results Ten different SPAST mutations were identified in 11 probands, of which the following 6 were novel: c.760A>T, c.131C>A, c.1351_1353delAGA, c.376_377dupTA, c.1114A>G, and c.1372A>C. Most patients with SPAST mutations had AD-HSP (10/11, 91%), and the frequency of SPAST mutations accounted for 66.7% (10/15) of the AD-HSP patients. No significant correlation was found between the presence of the SPAST mutation and any of the various clinical parameters of pure HSP. No ATL1 and REEP1 mutations were detected. Conclusions We conclude that SPAST mutations are responsible for most Korean cases of genetically confirmed AD-HSP. Our observation of the absence of ATL1 and REEP1 mutations needs to be confirmed in larger series.
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Affiliation(s)
- Tae-Hyoung Kim
- Department of Neurology, Pusan National University School of Medicine, Yangsan, Korea. ; Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Jae-Hyeok Lee
- Department of Neurology, Pusan National University School of Medicine, Yangsan, Korea. ; Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Young-Eun Park
- Department of Neurology, Pusan National University School of Medicine, Yangsan, Korea
| | - Jin-Hong Shin
- Department of Neurology, Pusan National University School of Medicine, Yangsan, Korea. ; Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Tai-Seung Nam
- Department of Neurology, Chonnam National University Hospital, Gwangju, Korea
| | - Hyang-Sook Kim
- Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Ho-Jung Jang
- Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Artem Semenov
- Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Sang Jin Kim
- Department of Neurology, Busan Paik Hospital, Inje University College of Medicine, Busan, Korea
| | - Dae-Seong Kim
- Department of Neurology, Pusan National University School of Medicine, Yangsan, Korea. ; Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, Korea
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Park SH, Zhu PP, Parker RL, Blackstone C. Hereditary spastic paraplegia proteins REEP1, spastin, and atlastin-1 coordinate microtubule interactions with the tubular ER network. J Clin Invest 2010; 120:1097-110. [PMID: 20200447 DOI: 10.1172/jci40979] [Citation(s) in RCA: 284] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2009] [Accepted: 01/06/2010] [Indexed: 12/15/2022] Open
Abstract
Hereditary spastic paraplegias (HSPs; SPG1-45) are inherited neurological disorders characterized by lower extremity spastic weakness. More than half of HSP cases result from autosomal dominant mutations in atlastin-1 (also known as SPG3A), receptor expression enhancing protein 1 (REEP1; SPG31), or spastin (SPG4). The atlastin-1 GTPase interacts with spastin, a microtubule-severing ATPase, as well as with the DP1/Yop1p and reticulon families of ER-shaping proteins, and SPG3A caused by atlastin-1 mutations has been linked pathogenically to abnormal ER morphology. Here we investigated SPG31 by analyzing the distribution, interactions, and functions of REEP1. We determined that REEP1 is structurally related to the DP1/Yop1p family of ER-shaping proteins and localizes to the ER in cultured rat cerebral cortical neurons, where it colocalizes with spastin and atlastin-1. Upon overexpression in COS7 cells, REEP1 formed protein complexes with atlastin-1 and spastin within the tubular ER, and these interactions required hydrophobic hairpin domains in each of these proteins. REEP proteins were required for ER network formation in vitro, and REEP1 also bound microtubules and promoted ER alignment along the microtubule cytoskeleton in COS7 cells. A SPG31 mutant REEP1 lacking the C-terminal cytoplasmic region did not interact with microtubules and disrupted the ER network. These data indicate that the HSP proteins atlastin-1, spastin, and REEP1 interact within the tubularER membrane in corticospinal neurons to coordinate ER shaping and microtubule dynamics. Thus, defects in tubular ER shaping and network interactions with the microtubule cytoskeleton seem to be the predominant pathogenic mechanism of HSP.
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Affiliation(s)
- Seong H Park
- Cellular Neurology Unit, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke (NINDS), NIH, Bethesda, Maryland 20892-3738, USA
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Lim JS, Sung JJ, Hong YH, Park SS, Park KS, Cha JI, Lee JY, Lee KW. A novel splicing mutation (c.870+3A>G) in SPG4 in a Korean family with hereditary spastic paraplegia. J Neurol Sci 2009; 290:186-9. [PMID: 19939411 DOI: 10.1016/j.jns.2009.10.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2009] [Revised: 10/10/2009] [Accepted: 10/15/2009] [Indexed: 11/15/2022]
Abstract
Hereditary spastic paraplegia (HSP) is a group of genetically heterogenous neurodegenerative disorders characterized by progressive spasticity and weakness of both lower extremities. Herein, we report a novel splicing mutation (c.870+3A>G) in SPG4 in a Korean family with an autosomal dominant-inherited pure HSP. The mutation is located in intron 5, and results in a deletion of the 188bp-sized exon 5. It is likely that the exon 5 deletion leads to spastin dysfunction and cause the typical symptoms and signs of patients.
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Affiliation(s)
- Jae-Sung Lim
- Department of Neurology, Seoul National University Hospital, Seoul, 28 Yeongeon-dong, Jongno-gu, Seoul 110-744, Republic of Korea
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Ribaï P, Depienne C, Fedirko E, Jothy AC, Viveweger C, Hahn-Barma V, Brice A, Durr A. Mental deficiency in three families with SPG4 spastic paraplegia. Eur J Hum Genet 2007; 16:97-104. [DOI: 10.1038/sj.ejhg.5201922] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Beetz C, Zuchner S, Ashley-Koch A, Auer-Grumbach M, Byrne P, Chinnery PF, Hutchinson M, McDermott CJ, Meijer IA, Nygren AOH, Pericak-Vance M, Pyle A, Rouleau GA, Schickel J, Shaw PJ, Deufel T. Linkage to a known gene but no mutation identified: comprehensive reanalysis of SPG4 HSP pedigrees reveals large deletions as the sole cause. Hum Mutat 2007; 28:739-40. [PMID: 17345589 DOI: 10.1002/humu.20508] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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McDermott CJ, Shaw PJ. Chapter 17 Hereditary spastic paraparesis. HANDBOOK OF CLINICAL NEUROLOGY 2007; 82:327-352. [PMID: 18808902 DOI: 10.1016/s0072-9752(07)80020-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
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Basri R, Yabe I, Soma H, Takei A, Nishimura H, Machino Y, Kokubo Y, Kosugi M, Okada R, Yukitake M, Tachibana H, Kuroda Y, Kuzuhara S, Sasaki H. Four mutations of the spastin gene in Japanese families with spastic paraplegia. J Hum Genet 2006; 51:711-715. [PMID: 16788734 DOI: 10.1007/s10038-006-0412-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2006] [Accepted: 04/07/2006] [Indexed: 10/24/2022]
Abstract
Hereditary spastic paraplegia (HSP) is a group of genetically heterogeneous neurodegenerative disorders characterized by slowly progressive spasticity and weakness of the lower limbs. HSP is caused by failure of development or selective degeneration of the corticospinal tracts, which contain the longest axons in humans. The most common form of HSP is caused by mutations of the spastin gene (SPAST), located on chromosome 2p21-p22, which encodes spastin, one of the ATPases associated with diverse cellular activities (AAA). In this study, we detected four causative mutations of SPAST among 14 unrelated patients with spastic paraplegia. Two missense mutations (1447A-->G, 1207C-->G) and two deletion mutations (1465delT, 1475-1476delAA) were located in the AAA cassette region. Three of these four mutations were novel. Previous reports and our results suggest that the frequency of SPAST mutations is higher among Japanese patients with autosomal dominant HSP, although SPAST mutations are also observed in patients with sporadic spastic paraplegia.
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Affiliation(s)
- Rehana Basri
- Department of Neurology, Graduate School of Medicine, Hokkaido University, Kita-ku, Sapporo, 060-8368, Japan
| | - Ichiro Yabe
- Department of Neurology, Graduate School of Medicine, Hokkaido University, Kita-ku, Sapporo, 060-8368, Japan
| | - Hiroyuki Soma
- Department of Neurology, Graduate School of Medicine, Hokkaido University, Kita-ku, Sapporo, 060-8368, Japan
| | - Asako Takei
- Hokuyukai Neurology Hospital, Sapporo, Japan
| | - Hiroyuki Nishimura
- Department of Internal Medicine, Division of Neurology and Stroke Care Unit, Hyogo College of Medicine, Nishinomiya, Japan
| | - Yuka Machino
- Department of Neurology, Graduate School of Medicine, Mie University, Tsu, Japan
| | - Yasumasa Kokubo
- Department of Neurology, Graduate School of Medicine, Mie University, Tsu, Japan
| | - Masafumi Kosugi
- Department of Neurology, Graduate School of Medicine, Saga University, Saga, Japan
| | - Ryuichirou Okada
- Department of Neurology, Graduate School of Medicine, Saga University, Saga, Japan
| | - Motohiro Yukitake
- Department of Neurology, Graduate School of Medicine, Saga University, Saga, Japan
| | - Hisao Tachibana
- Department of General Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan
| | - Yasuo Kuroda
- Department of Neurology, Graduate School of Medicine, Saga University, Saga, Japan
| | - Shigeki Kuzuhara
- Department of Neurology, Graduate School of Medicine, Mie University, Tsu, Japan
| | - Hidenao Sasaki
- Department of Neurology, Graduate School of Medicine, Hokkaido University, Kita-ku, Sapporo, 060-8368, Japan.
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Magariello A, Muglia M, Patitucci A, Mazzei R, Conforti FL, Gabriele AL, Sprovieri T, Ungaro C, Gambardella A, Mancuso M, Siciliano G, Branca D, Aguglia U, de Angelis MV, Longo K, Quattrone A. Novel spastin (SPG4) mutations in Italian patients with hereditary spastic paraplegia. Neuromuscul Disord 2006; 16:387-90. [PMID: 16684598 DOI: 10.1016/j.nmd.2006.03.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2005] [Revised: 02/14/2006] [Accepted: 03/16/2006] [Indexed: 10/24/2022]
Abstract
Spastic paraplegia type 4 is caused by mutations in the gene that encodes spastin (SPG4), a member of the AAA protein family. A cohort of 34 unrelated Italian patients with pure spastic paraplegia, of which 18 displayed autosomal dominant inheritance and 16 were apparently sporadic, were screened for mutations in the SPG4 gene by denaturing high performance liquid chromatography. We identified a previously reported mutation in a sporadic patient with pure hereditary spastic paraplegia. We also identified eight unrelated patients with pure autosomal dominant hereditary spastic paraplegia carrying five novel mutations in the SPG4 gene (one missense mutation, c.1304 C>T; one nonsense mutation, c.807C>A; two frameshift mutations, c.1281dupT, c.1514_1515insATA; and one splicing mutation, c.1322-2A>C). The frequency for SPG4 mutations detected in autosomal dominant hereditary spastic paraplegia was 44.4%. This study contributes to expand the spectrum of SPG4 mutations in Italian population.
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Affiliation(s)
- Angela Magariello
- Institute of Neurological Sciences, National Research Council, Mangone, Cosenza, Italy
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Mannan AU, Boehm J, Sauter SM, Rauber A, Byrne PC, Neesen J, Engel W. Spastin, the most commonly mutated protein in hereditary spastic paraplegia interacts with Reticulon 1 an endoplasmic reticulum protein. Neurogenetics 2006; 7:93-103. [PMID: 16602018 DOI: 10.1007/s10048-006-0034-4] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2005] [Accepted: 02/14/2006] [Indexed: 12/11/2022]
Abstract
Spastin, an ATPase belonging to the AAA family of proteins is most commonly mutated in autosomal dominant hereditary spastic paraplegias (HSP). Spastin is a multifaceted protein with versatile role in cellular events, principally involved in microtubule dynamics. To gain further insight into the molecular function of spastin, we used the yeast two-hybrid approach to identify novel interacting partners of spastin. Using spastin as bait, we identified reticulon 1 (RTN1) and reticulon 3 (RTN3) as potential spastin interacting proteins. RTN1 and RTN3 belong to the reticulon (RTN) gene family, which are primarily expressed in the endoplasmic reticulum. Moreover, RTN1 is known to play a role in vesicular transport processes. Using in vitro and in vivo immunoprecipitation experiments, we were able to demonstrate that RTN1 interacts specifically with spastin. Intracellular distribution studies using immunostaining and overexpression of epitope-tagged protein revealed an obvious colocalization of spastin and RTN1 in discrete vesicles in the cytoplasm. Spastin mediates its interaction with RTN1 through its N-terminal region containing a microtubule-interacting and trafficking domain. It is interesting to note that the aberrant intracellular distribution of a truncated spastin protein was rescued by coexpression with RTN1, which highlights the physiological significance of this interaction. Our findings strengthen the hypothesis that disruption of intracellular vesicular transport processes could cause HSP. It is interesting to note that RTN1 is localized to 14q23.1 where SPG15 locus was mapped. Therefore, we considered RTN1 as a candidate gene for the SPG15 locus, but our mutational analysis possibly excludes RTN1 as causative gene.
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Affiliation(s)
- Ashraf U Mannan
- Institute of Human Genetics, University of Goettingen, Heinrich-Dueker-Weg 12, Goettingen 37073, Germany.
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Iwanaga H, Tsujino A, Shirabe S, Eguchi H, Fukushima N, Niikawa N, Yoshiura KI, Eguchi K. Large deletion involving the 5'-UTR in the spastin gene caused mild phenotype of autosomal dominant hereditary spastic paraplegia. Am J Med Genet A 2005; 133A:13-7. [PMID: 15637712 DOI: 10.1002/ajmg.a.30510] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Hereditary spastic paraplegia (HSP) due to mutations in the spastin gene (SPG4) located to 2p22-p21 is the most common form of autosomal dominant (AD) HSP. We performed PCR-based direct sequencing of SPG4, followed by a linkage analysis and subsequent Southern blot analysis in large Japanese kindred where 20 of 33 members were evaluated neurologically, and consequently 6 were affected with HSP. Clinical evaluation showed that the mean age at disease onset of the patients was older and the disability was less severe than those of previously reported typical patients with SPG4 mutations. Direct sequencing of genomic DNA and RT-PCR product did not show a SPG4 mutation despite of a strong linkage to the SPG4 locus at 2p. Southern blot analysis suggested a deletion involving the 5'-UTR of SPG4. Further sequence analysis confirmed a heterozygous 2307-bp deletion spanning from the 5'-UTR to intron 1 of SPG4. The results suggested that transcription of the mutated allele starts from an authentic initiation site, but lacks an authentic translational start site of exon 1 because of a deficient splice donor site and coding region. The abnormal transcripts may result in rapid RNA decay. The novel refractory mutation we identified widens the spectrum of SPG4 mutations. These findings suggest that structural genomic abnormalities of SPG4 are more frequent than expected, and this explains previously reported cases more feasibly in which SPG4 mutations were failed to be identified but the disease was linked to 2p.
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Affiliation(s)
- Hiroshi Iwanaga
- First Department of Internal Medicine, Nagasaki University Graduate School of Biomedical Sciences, Sakamoto, Nagasaki, Japan
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