1
|
Rios JJ, Li Y, Paria N, Bohlender RJ, Huff C, Rosenfeld JA, Liu P, Bi W, Haga K, Fukuda M, Vashisth S, Kaur K, Chahrour MH, Bober MB, Duker AL, Ladha FA, Hanchard NA, Atala K, Khanshour AM, Smith L, Wise CA, Delgado MR. RAB1A haploinsufficiency phenocopies the 2p14-p15 microdeletion and is associated with impaired neuronal differentiation. Am J Hum Genet 2023; 110:2103-2111. [PMID: 37924809 PMCID: PMC10722380 DOI: 10.1016/j.ajhg.2023.10.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 10/09/2023] [Accepted: 10/10/2023] [Indexed: 11/06/2023] Open
Abstract
Hereditary spastic parapareses (HSPs) are clinically heterogeneous motor neuron diseases with variable age of onset and severity. Although variants in dozens of genes are implicated in HSPs, much of the genetic basis for pediatric-onset HSP remains unexplained. Here, we re-analyzed clinical exome-sequencing data from siblings with HSP of unknown genetic etiology and identified an inherited nonsense mutation (c.523C>T [p.Arg175Ter]) in the highly conserved RAB1A. The mutation is predicted to produce a truncated protein with an intact RAB GTPase domain but without two C-terminal cysteine residues required for proper subcellular protein localization. Additional RAB1A mutations, including two frameshift mutations and a mosaic missense mutation (c.83T>C [p.Leu28Pro]), were identified in three individuals with similar neurodevelopmental presentations. In rescue experiments, production of the full-length, but not the truncated, RAB1a rescued Golgi structure and cell proliferation in Rab1-depleted cells. In contrast, the missense-variant RAB1a disrupted Golgi structure despite intact Rab1 expression, suggesting a dominant-negative function of the mosaic missense mutation. Knock-down of RAB1A in cultured human embryonic stem cell-derived neurons resulted in impaired neuronal arborization. Finally, RAB1A is located within the 2p14-p15 microdeletion syndrome locus. The similar clinical presentations of individuals with RAB1A loss-of-function mutations and the 2p14-p15 microdeletion syndrome implicate loss of RAB1A in the pathogenesis of neurodevelopmental manifestations of this microdeletion syndrome. Our study identifies a RAB1A-related neurocognitive disorder with speech and motor delay, demonstrates an essential role for RAB1a in neuronal differentiation, and implicates RAB1A in the etiology of the neurodevelopmental sequelae associated with the 2p14-p15 microdeletion syndrome.
Collapse
Affiliation(s)
- Jonathan J Rios
- Center for Pediatric Bone Biology and Translational Research, Scottish Rite for Children, Dallas, TX 75219, USA; Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Departments of Pediatrics University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Orthopaedic Surgery, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Yang Li
- Center for Pediatric Bone Biology and Translational Research, Scottish Rite for Children, Dallas, TX 75219, USA
| | - Nandina Paria
- Center for Pediatric Bone Biology and Translational Research, Scottish Rite for Children, Dallas, TX 75219, USA
| | - Ryan J Bohlender
- Department of Epidemiology, MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Chad Huff
- Department of Epidemiology, MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Jill A Rosenfeld
- Department of Molecular & Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Baylor Genetics, Houston, TX 77021, USA
| | - Pengfei Liu
- Department of Molecular & Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Baylor Genetics, Houston, TX 77021, USA
| | - Weimin Bi
- Department of Molecular & Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Baylor Genetics, Houston, TX 77021, USA
| | - Kentaro Haga
- Department of Integrative Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Mitsunori Fukuda
- Department of Integrative Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Shayal Vashisth
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Kiran Kaur
- Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Maria H Chahrour
- Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Peter O'Donnell Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Michael B Bober
- Nemours Children's Hospital, Wilmington, DE 19803, USA; Thomas Jefferson University, Philadelphia, PA 19144, USA
| | | | - Farah A Ladha
- Department of Molecular & Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Neil A Hanchard
- Department of Molecular & Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Kristhen Atala
- Center for Pediatric Bone Biology and Translational Research, Scottish Rite for Children, Dallas, TX 75219, USA
| | - Anas M Khanshour
- Center for Pediatric Bone Biology and Translational Research, Scottish Rite for Children, Dallas, TX 75219, USA
| | - Linsley Smith
- Department of Neurology, Scottish Rite for Children, Dallas, TX 75219, USA
| | - Carol A Wise
- Center for Pediatric Bone Biology and Translational Research, Scottish Rite for Children, Dallas, TX 75219, USA; Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Departments of Pediatrics University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Orthopaedic Surgery, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Mauricio R Delgado
- Department of Neurology, Scottish Rite for Children, Dallas, TX 75219, USA; Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| |
Collapse
|
2
|
Parodi L, Barbier M, Jacoupy M, Pujol C, Lejeune FX, Lallemant-Dudek P, Esteves T, Pennings M, Kamsteeg EJ, Guillaud-Bataille M, Banneau G, Coarelli G, Oumoussa BM, Fraidakis MJ, Stevanin G, Depienne C, van de Warrenburg B, Brice A, Durr A. The mitochondrial seryl-tRNA synthetase SARS2 modifies onset in spastic paraplegia type 4. Genet Med 2022; 24:2308-2317. [PMID: 36056923 DOI: 10.1016/j.gim.2022.07.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 07/24/2022] [Accepted: 07/25/2022] [Indexed: 11/25/2022] Open
Abstract
PURPOSE Hereditary spastic paraplegia type 4 is extremely variable in age at onset; the same variant can cause onset at birth or in the eighth decade. We recently discovered that missense variants in SPAST, which influences microtubule dynamics, are associated with earlier onset and more severe disease than truncating variants, but even within the early and late-onset groups there remained significant differences in onset. Given the rarity of the condition, we adapted an extreme phenotype approach to identify genetic modifiers of onset. METHODS We performed a genome-wide association study on 134 patients bearing truncating pathogenic variants in SPAST, divided into early- and late-onset groups (aged ≤15 and ≥45 years, respectively). A replication cohort of 419 included patients carrying either truncating or missense variants. Finally, age at onset was analyzed in the merged cohort (N = 553). RESULTS We found 1 signal associated with earlier age at onset (rs10775533, P = 8.73E-6) in 2 independent cohorts and in the merged cohort (N = 553, Mantel-Cox test, P < .0001). Western blotting in lymphocytes of 20 patients showed that this locus tends to upregulate SARS2 expression in earlier-onset patients. CONCLUSION SARS2 overexpression lowers the age of onset in hereditary spastic paraplegia type 4. Lowering SARS2 or improving mitochondrial function could thus present viable approaches to therapy.
Collapse
Affiliation(s)
- Livia Parodi
- Paris Brain Institute (Institut du Cerveau, ICM), INSERM, CNRS, Assistance Publique-Hôpitaux de Paris (AP-HP), Sorbonne Université, Paris, France
| | - Mathieu Barbier
- Paris Brain Institute (Institut du Cerveau, ICM), INSERM, CNRS, Assistance Publique-Hôpitaux de Paris (AP-HP), Sorbonne Université, Paris, France
| | - Maxime Jacoupy
- Paris Brain Institute (Institut du Cerveau, ICM), INSERM, CNRS, Assistance Publique-Hôpitaux de Paris (AP-HP), Sorbonne Université, Paris, France
| | - Claire Pujol
- Paris Brain Institute (Institut du Cerveau, ICM), INSERM, CNRS, Assistance Publique-Hôpitaux de Paris (AP-HP), Sorbonne Université, Paris, France; Pasteur Institute, Centre National de la Recherche Scientifique UMR 3691, Paris, France
| | - François-Xavier Lejeune
- Paris Brain Institute (Institut du Cerveau, ICM), INSERM, CNRS, Assistance Publique-Hôpitaux de Paris (AP-HP), Sorbonne Université, Paris, France
| | - Pauline Lallemant-Dudek
- Paris Brain Institute (Institut du Cerveau, ICM), INSERM, CNRS, Assistance Publique-Hôpitaux de Paris (AP-HP), Sorbonne Université, Paris, France
| | - Typhaine Esteves
- Paris Brain Institute (Institut du Cerveau, ICM), INSERM, CNRS, Assistance Publique-Hôpitaux de Paris (AP-HP), Sorbonne Université, Paris, France; Université de Bordeaux, CNRS, EPHE, INCIA, UMR 5287, Bordeaux, France
| | - Maartje Pennings
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Erik-Jan Kamsteeg
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | | | - Guillaume Banneau
- Département de Génétique, AP-HP, GH Pitié-Salpêtrière, Sorbonne Université, Paris, France
| | - Giulia Coarelli
- Paris Brain Institute (Institut du Cerveau, ICM), INSERM, CNRS, Assistance Publique-Hôpitaux de Paris (AP-HP), Sorbonne Université, Paris, France
| | - Badreddine Mohand Oumoussa
- Sorbonne Université, Inserm, UMS Production et Analyse des données en Sciences de la vie et en Santé, PASS, Plateforme Post-génomique de la Pitié-Salpêtrière, P3S, Paris, France
| | - Matthew J Fraidakis
- Rare Neurological Diseases Unit, Department of Neurology, Attikon University Hospital, Medical School of the University of Athens, Athens, Greece
| | - Giovanni Stevanin
- Paris Brain Institute (Institut du Cerveau, ICM), INSERM, CNRS, Assistance Publique-Hôpitaux de Paris (AP-HP), Sorbonne Université, Paris, France; Université de Bordeaux, CNRS, EPHE, INCIA, UMR 5287, Bordeaux, France
| | - Christel Depienne
- Paris Brain Institute (Institut du Cerveau, ICM), INSERM, CNRS, Assistance Publique-Hôpitaux de Paris (AP-HP), Sorbonne Université, Paris, France; Institut für Humangenetik, Universitätsklinikum Essen, Essen, Germany
| | - Bart van de Warrenburg
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Alexis Brice
- Paris Brain Institute (Institut du Cerveau, ICM), INSERM, CNRS, Assistance Publique-Hôpitaux de Paris (AP-HP), Sorbonne Université, Paris, France
| | - Alexandra Durr
- Paris Brain Institute (Institut du Cerveau, ICM), INSERM, CNRS, Assistance Publique-Hôpitaux de Paris (AP-HP), Sorbonne Université, Paris, France.
| |
Collapse
|
3
|
Panza E, Meyyazhagan A, Orlacchio A. Hereditary spastic paraplegia: Genetic heterogeneity and common pathways. Exp Neurol 2022; 357:114203. [PMID: 35970204 DOI: 10.1016/j.expneurol.2022.114203] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 07/11/2022] [Accepted: 08/09/2022] [Indexed: 02/07/2023]
Abstract
Hereditary Spastic Paraplegias (HSPs) are a heterogeneous group of disease, mainly characterized by progressive spasticity and weakness of the lower limbs resulting from distal degeneration of corticospinal tract axons. Although HSPs represent rare or ultra-rare conditions, with reported cases of mutated genes found in single families, overall, with 87 forms described, they are an important health and economic problem for society and patients. In fact, they are chronic and life-hindering conditions, still lacking a specific therapy. Notwithstanding the number of forms described, and 73 causative genes identified, overall, the molecular diagnostic rate varies among 29% to 61.8%, based on recent published analysis, suggesting that more genes are involved in HSP and/or that different molecular diagnostic approaches are necessary. The accumulating data in this field highlight several peculiar features of HSPs, such as genetic heterogeneity, the discovery that different mutations in a single gene can be transmitted in dominant and recessive trait in families and allelic heterogeneity, resulting in the involvement of HSP-genes in other conditions. Based on the observation of protein functions, the activity of many different proteins encoded by HSP-related genes converges into some distinct pathophysiological mechanisms. This suggests that common pathways could be a potential target for a therapy, possibly addressing several forms at once. Furthermore, the overlap of HSP genes with other neurological conditions can further expand this concept.
Collapse
Affiliation(s)
- Emanuele Panza
- Dipartimento di Scienze Mediche e Chirurgiche, Università di Bologna, Bologna, Italy
| | - Arun Meyyazhagan
- Dipartimento di Medicina e Chirurgia, Università di Perugia, Perugia, Italy
| | - Antonio Orlacchio
- Dipartimento di Medicina e Chirurgia, Università di Perugia, Perugia, Italy; Laboratorio di Neurogenetica, Centro Europeo di Ricerca sul Cervello (CERC), Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Fondazione Santa Lucia, Rome, Italy.
| |
Collapse
|
4
|
Hereditary spastic paraplegia type 56: what a mouse can tell – a narrative review. JOURNAL OF BIO-X RESEARCH 2022. [DOI: 10.1097/jbr.0000000000000127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
|
5
|
Varghaei P, Estiar MA, Ashtiani S, Veyron S, Mufti K, Leveille E, Yu E, Spiegelman D, Rioux MF, Yoon G, Tarnopolsky M, Boycott KM, Dupre N, Suchowersky O, Trempe JF, Rouleau GA, Gan-Or Z. Genetic, structural and clinical analysis of spastic paraplegia 4. Parkinsonism Relat Disord 2022; 98:62-69. [PMID: 35487127 DOI: 10.1016/j.parkreldis.2022.03.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 03/26/2022] [Accepted: 03/30/2022] [Indexed: 01/08/2023]
Abstract
INTRODUCTION Spastic paraplegia type 4 (SPG4), resulting from heterozygous mutations in the SPAST gene, is the most common form among the heterogeneous group of hereditary spastic paraplegias (HSPs). We aimed to study genetic and clinical characteristics of SPG4 across Canada. METHODS The SPAST gene was analyzed in a total of 696 HSP patients from 431 families by either HSP-gene panel sequencing or whole exome sequencing (WES). We used Multiplex ligation-dependent probe amplification to analyze copy number variations (CNVs), and performed in silico structural analysis of selected mutations. Clinical characteristics of patients were assessed, and long-term follow-up was done to study genotype-phenotype correlations. RESULTS We identified 157 SPG4 patients from 65 families who carried 41 different SPAST mutations, six of which are novel and six are CNVs. We report novel aspects of mutations occurring in Arg499, a case with homozygous mutation, a family with probable compound heterozygous mutations, three patients with de novo mutations, three cases with pathogenic synonymous mutation, co-occurrence of SPG4 and clinically isolated syndrome, and novel or rarely reported signs and symptoms seen in SPG4 patients. CONCLUSION Our study demonstrates that SPG4 is a heterogeneous type of HSP, with diverse genetic features and clinical manifestations. In rare cases, biallelic inheritance, de novo mutation, pathogenic synonymous mutations and CNVs should be considered.
Collapse
Affiliation(s)
- Parizad Varghaei
- Division of Experimental Medicine, Department of Medicine, McGill University, Montreal, Quebec, Canada; The Neuro (Montreal Neurological Institute-Hospital), McGill University, Montreal, Quebec, Canada
| | - Mehrdad A Estiar
- The Neuro (Montreal Neurological Institute-Hospital), McGill University, Montreal, Quebec, Canada; Department of Human Genetics, McGill University, Montréal, Québec, Canada
| | - Setareh Ashtiani
- Alberta Children's Hospital, Medical Genetics, Calgary, Alberta, Canada
| | - Simon Veyron
- Department of Pharmacology & Therapeutics and Centre de Recherche en Biologie Structurale - FRQS, McGill University, Montréal, Canada
| | - Kheireddin Mufti
- The Neuro (Montreal Neurological Institute-Hospital), McGill University, Montreal, Quebec, Canada; Department of Human Genetics, McGill University, Montréal, Québec, Canada
| | | | - Eric Yu
- The Neuro (Montreal Neurological Institute-Hospital), McGill University, Montreal, Quebec, Canada; Department of Human Genetics, McGill University, Montréal, Québec, Canada
| | - Dan Spiegelman
- The Neuro (Montreal Neurological Institute-Hospital), McGill University, Montreal, Quebec, Canada
| | - Marie-France Rioux
- Department of Neurology, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Grace Yoon
- Divisions of Neurology and Clinical and Metabolic Genetics, Department of Paediatrics, University of Toronto, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Mark Tarnopolsky
- Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada
| | - Kym M Boycott
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Nicolas Dupre
- Department of Medicine, Faculty of Medicine, Université Laval, Québec City, Quebec, Canada; Neuroscience Axis, CHU de Québec-Université Laval, Québec City, Québec, Canada
| | - Oksana Suchowersky
- Alberta Children's Hospital, Medical Genetics, Calgary, Alberta, Canada; Departments of Medicine (Neurology) and Medical Genetics, University of Alberta, Edmonton, Alberta, Canada
| | - Jean-François Trempe
- Department of Pharmacology & Therapeutics and Centre de Recherche en Biologie Structurale - FRQS, McGill University, Montréal, Canada
| | - Guy A Rouleau
- The Neuro (Montreal Neurological Institute-Hospital), McGill University, Montreal, Quebec, Canada; Department of Human Genetics, McGill University, Montréal, Québec, Canada; Department of Neurology and Neurosurgery, McGill University, Montréal, Québec, Canada.
| | - Ziv Gan-Or
- The Neuro (Montreal Neurological Institute-Hospital), McGill University, Montreal, Quebec, Canada; Department of Human Genetics, McGill University, Montréal, Québec, Canada; Department of Neurology and Neurosurgery, McGill University, Montréal, Québec, Canada.
| |
Collapse
|
6
|
Rossi S, Rubegni A, Riso V, Barghigiani M, Bassi MT, Battini R, Bertini E, Cereda C, Cioffi E, Criscuolo C, Dal Fabbro B, Dato C, D'Angelo MG, Di Muzio A, Diamanti L, Dotti MT, Filla A, Gioiosa V, Liguori R, Martinuzzi A, Massa R, Mignarri A, Moroni R, Musumeci O, Nicita F, Orologio I, Orsi L, Pegoraro E, Petrucci A, Plumari M, Ricca I, Rizzo G, Romano S, Rumore R, Sampaolo S, Scarlato M, Seri M, Stefan C, Straccia G, Tessa A, Travaglini L, Trovato R, Ulgheri L, Vazza G, Orlacchio A, Silvestri G, Santorelli FM, Melone MAB, Casali C. Clinical-Genetic Features Influencing Disability in Spastic Paraplegia Type 4. Neurol Genet 2022; 8:e664. [PMID: 35372684 PMCID: PMC8969300 DOI: 10.1212/nxg.0000000000000664] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 01/31/2022] [Indexed: 11/15/2022]
Abstract
Background and ObjectivesHereditary spastic paraplegias (HSPs) are a group of inherited rare neurologic disorders characterized by length-dependent degeneration of the corticospinal tracts and dorsal columns, whose prominent clinical feature is represented by spastic gait. Spastic paraplegia type 4 (SPG4, SPAST-HSP) is the most common form. We present both clinical and molecular findings of a large cohort of patients, with the aim of (1) defining the clinical spectrum of SPAST-HSP in Italy; (2) describing their molecular features; and (3) assessing genotype-phenotype correlations to identify features associated with worse disability.MethodsA cross-sectional retrospective study with molecular and clinical data collected in an anonymized database was performed.ResultsA total of 723 Italian patients with SPAST-HSP (58% men) from 316 families, with a median age at onset of 35 years, were included. Penetrance was 97.8%, with men showing higher Spastic Paraplegia Rating Scale (SPRS) scores (19.67 ± 12.58 vs 16.15 ± 12.61, p = 0.009). In 26.6% of patients with SPAST-HSP, we observed a complicated phenotype, mainly including intellectual disability (8%), polyneuropathy (6.7%), and cognitive decline (6.5%). Late-onset cases seemed to progress more rapidly, and patients with a longer disease course displayed a more severe neurologic disability, with higher SPATAX (3.61 ± 1.46 vs 2.71 ± 1.20, p < 0.001) and SPRS scores (22.63 ± 11.81 vs 12.40 ± 8.83, p < 0.001). Overall, 186 different variants in the SPAST gene were recorded, of which 48 were novel. Patients with SPAST-HSP harboring missense variants displayed intellectual disability (14.5% vs 4.4%, p < 0.001) more frequently, whereas patients with truncating variants presented more commonly cognitive decline (9.7% vs 2.6%, p = 0.001), cerebral atrophy (11.2% vs 3.4%, p = 0.003), lower limb spasticity (61.5% vs 44.5%), urinary symptoms (50.0% vs 31.3%, p < 0.001), and sensorimotor polyneuropathy (11.1% vs 1.1%, p < 0.001). Increasing disease duration (DD) and abnormal motor evoked potentials (MEPs) were also associated with increased likelihood of worse disability (SPATAX score>3).DiscussionThe SPAST-HSP phenotypic spectrum in Italian patients confirms a predominantly pure form of HSP with mild-to-moderate disability in 75% of cases, and slight prevalence of men, who appeared more severely affected. Early-onset cases with intellectual disability were more frequent among patients carrying missense SPAST variants, whereas patients with truncating variants showed a more complicated disease. Both longer DD and altered MEPs are associated with worse disability.
Collapse
|
7
|
Elsayed LEO, Eltazi IZ, Ahmed AE, Stevanin G. Insights into Clinical, Genetic, and Pathological Aspects of Hereditary Spastic Paraplegias: A Comprehensive Overview. Front Mol Biosci 2021; 8:690899. [PMID: 34901147 PMCID: PMC8662366 DOI: 10.3389/fmolb.2021.690899] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Accepted: 10/19/2021] [Indexed: 12/31/2022] Open
Abstract
Hereditary spastic paraplegias (HSP) are a heterogeneous group of motor neurodegenerative disorders that have the core clinical presentation of pyramidal syndrome which starts typically in the lower limbs. They can present as pure or complex forms with all classical modes of monogenic inheritance reported. To date, there are more than 100 loci/88 spastic paraplegia genes (SPG) involved in the pathogenesis of HSP. New patterns of inheritance are being increasingly identified in this era of huge advances in genetic and functional studies. A wide range of clinical symptoms and signs are now reported to complicate HSP with increasing overall complexity of the clinical presentations considered as HSP. This is especially true with the emergence of multiple HSP phenotypes that are situated in the borderline zone with other neurogenetic disorders. The genetic diagnostic approaches and the utilized techniques leave a diagnostic gap of 25% in the best studies. In this review, we summarize the known types of HSP with special focus on those in which spasticity is the principal clinical phenotype ("SPGn" designation). We discuss their modes of inheritance, clinical phenotypes, underlying genetics, and molecular pathways, providing some observations about therapeutic opportunities gained from animal models and functional studies. This review may pave the way for more analytic approaches that take into consideration the overall picture of HSP. It will shed light on subtle associations that can explain the occurrence of the disease and allow a better understanding of its observed variations. This should help in the identification of future biomarkers, predictors of disease onset and progression, and treatments for both better functional outcomes and quality of life.
Collapse
Affiliation(s)
- Liena E. O. Elsayed
- Department of Basic Sciences, College of Medicine, Princess Nourah bint Abdulrahman University [PNU], Riyadh, Saudi Arabia
- Faculty of Medicine, University of Khartoum, Khartoum, Sudan
| | | | - Ammar E. Ahmed
- Faculty of Medicine, University of Khartoum, Khartoum, Sudan
| | - Giovanni Stevanin
- Institut du Cerveau – Paris Brain Institute - ICM, Sorbonne Université, INSERM, CNRS, APHP, Paris, France
- CNRS, INCIA, Université de Bordeaux, Bordeaux, France
- Ecole Pratique des Hautes Etudes, EPHE, PSL Research University, Paris, France
| |
Collapse
|
8
|
Darios F, Coarelli G, Durr A. Genetics in hereditary spastic paraplegias: Essential but not enough. Curr Opin Neurobiol 2021; 72:8-14. [PMID: 34403957 DOI: 10.1016/j.conb.2021.07.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 06/04/2021] [Accepted: 07/14/2021] [Indexed: 12/01/2022]
Abstract
Hereditary spastic paraplegias consist of a group of rare neurodegenerative diseases characterized by lower limb spasticity. These inherited Mendelian disorders show high genetic variability associated with wide clinical diversity. Pathophysiological investigations have suggested that mutations in genes affecting the same cellular pathway generally lead to similar clinical symptoms, highlighting the importance of genetic mutation in these diseases. However, phenotype-genotype correlations have failed to explain the observed large inter-individual variability linked to mutations in a single gene, suggesting that genetics alone is not sufficient to explain symptom diversity. The identification of biomarkers, such as neurofilament light chain, could fill the gap and predict disease evolution.
Collapse
Affiliation(s)
- Frédéric Darios
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm U1127, CNRS UMR7225, Paris, 75013, France.
| | - Giulia Coarelli
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm U1127, CNRS UMR7225, Paris, 75013, France; AP-HP, Hôpital de la Pitié Salpêtrière, Paris, 75013, France
| | - Alexandra Durr
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm U1127, CNRS UMR7225, Paris, 75013, France; AP-HP, Hôpital de la Pitié Salpêtrière, Paris, 75013, France.
| |
Collapse
|
9
|
Lallemant-Dudek P, Darios F, Durr A. Recent advances in understanding hereditary spastic paraplegias and emerging therapies. Fac Rev 2021; 10:27. [PMID: 33817696 PMCID: PMC8009193 DOI: 10.12703/r/10-27] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Hereditary spastic paraplegias (HSPs) are a group of rare, inherited, neurological diseases characterized by broad clinical and genetic heterogeneity. Lower-limb spasticity with first motoneuron involvement is the core symptom of all HSPs. As spasticity is a syndrome and not a disease, it develops on top of other neurological signs (ataxia, dystonia, and parkinsonism). Indeed, the definition of genes responsible for HSPs goes beyond the 79 identified SPG genes. In order to avoid making a catalog of the different genes involved in HSP in any way, we have chosen to focus on the HSP with cerebellar ataxias since this is a frequent association described for several genes. This overlap leads to an intermediary group of spastic ataxias which is actively genetically and clinically studied. The most striking example is SPG7, which is responsible for HSP or cerebellar ataxia or both. There are no specific therapies against HSPs, and there is a dearth of randomized trials in patients with HSP, especially on spasticity when it likely results from other mechanisms. Thus far, no gene-specific therapy has been developed for HSP, but emerging therapies in animal models and neurons derived from induced pluripotent stem cells are potential treatments for patients.
Collapse
Affiliation(s)
- Pauline Lallemant-Dudek
- Paris Brain Institute (ICM), Inserm U 1127, CNRS UMR 7225, Sorbonne Université, Paris, France
| | - Frederic Darios
- Paris Brain Institute (ICM), Inserm U 1127, CNRS UMR 7225, Sorbonne Université, Paris, France
| | - Alexandra Durr
- Paris Brain Institute (ICM), Inserm U 1127, CNRS UMR 7225, Sorbonne Université, Paris, France
- Assistance Publique-Hôpitaux de Paris (AP-HP), Genetic Department, Pitié-Salpêtrière University Hospital, Paris, France
| |
Collapse
|
10
|
Estiar MA, Yu E, Haj Salem I, Ross JP, Mufti K, Akçimen F, Leveille E, Spiegelman D, Ruskey JA, Asayesh F, Dagher A, Yoon G, Tarnopolsky M, Boycott KM, Dupre N, Dion PA, Suchowersky O, Trempe JF, Rouleau GA, Gan-Or Z. Evidence for Non-Mendelian Inheritance in Spastic Paraplegia 7. Mov Disord 2021; 36:1664-1675. [PMID: 33598982 DOI: 10.1002/mds.28528] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 01/19/2021] [Accepted: 01/20/2021] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Although the typical inheritance of spastic paraplegia 7 is recessive, several reports have suggested that SPG7 variants may also cause autosomal dominant hereditary spastic paraplegia (HSP). OBJECTIVES We aimed to conduct an exome-wide genetic analysis on a large Canadian cohort of HSP patients and controls to examine the association of SPG7 and HSP. METHODS We analyzed 585 HSP patients from 372 families and 1175 controls, including 580 unrelated individuals. Whole-exome sequencing was performed on 400 HSP patients (291 index cases) and all 1175 controls. RESULTS The frequency of heterozygous pathogenic/likely pathogenic SPG7 variants (4.8%) among unrelated HSP patients was higher than among unrelated controls (1.7%; OR 2.88, 95% CI 1.24-6.66, P = 0.009). The heterozygous SPG7 p.(Ala510Val) variant was found in 3.7% of index patients versus 0.85% in unrelated controls (OR 4.42, 95% CI 1.49-13.07, P = 0.005). Similar results were obtained after including only genetically-undiagnosed patients. We identified four heterozygous SPG7 variant carriers with an additional pathogenic variant in known HSP genes, compared to zero in controls (OR 19.58, 95% CI 1.05-365.13, P = 0.0031), indicating potential digenic inheritance. We further identified four families with heterozygous variants in SPG7 and SPG7-interacting genes (CACNA1A, AFG3L2, and MORC2). Of these, there is especially compelling evidence for epistasis between SPG7 and AFG3L2. The p.(Ile705Thr) variant in AFG3L2 is located at the interface between hexamer subunits, in a hotspot of mutations associated with spinocerebellar ataxia type 28 that affect its proteolytic function. CONCLUSIONS Our results provide evidence for complex inheritance in SPG7-associated HSP, which may include recessive and possibly dominant and digenic/epistasis forms of inheritance. © 2021 International Parkinson and Movement Disorder Society.
Collapse
Affiliation(s)
- Mehrdad A Estiar
- Department of Human Genetics, McGill University, Montréal, Québec, Canada.,The Neuro (Montreal Neurological Institute-Hospital), McGill University, Montréal, Québec, Canada
| | - Eric Yu
- Department of Human Genetics, McGill University, Montréal, Québec, Canada.,The Neuro (Montreal Neurological Institute-Hospital), McGill University, Montréal, Québec, Canada
| | | | - Jay P Ross
- Department of Human Genetics, McGill University, Montréal, Québec, Canada.,The Neuro (Montreal Neurological Institute-Hospital), McGill University, Montréal, Québec, Canada
| | - Kheireddin Mufti
- Department of Human Genetics, McGill University, Montréal, Québec, Canada.,The Neuro (Montreal Neurological Institute-Hospital), McGill University, Montréal, Québec, Canada
| | - Fulya Akçimen
- Department of Human Genetics, McGill University, Montréal, Québec, Canada.,The Neuro (Montreal Neurological Institute-Hospital), McGill University, Montréal, Québec, Canada
| | - Etienne Leveille
- Faculty of Medicine, McGill University, Montréal, Québec, Canada
| | - Dan Spiegelman
- The Neuro (Montreal Neurological Institute-Hospital), McGill University, Montréal, Québec, Canada
| | - Jennifer A Ruskey
- The Neuro (Montreal Neurological Institute-Hospital), McGill University, Montréal, Québec, Canada
| | - Farnaz Asayesh
- The Neuro (Montreal Neurological Institute-Hospital), McGill University, Montréal, Québec, Canada
| | - Alain Dagher
- The Neuro (Montreal Neurological Institute-Hospital), McGill University, Montréal, Québec, Canada
| | - Grace Yoon
- Divisions of Neurology and Clinical and Metabolic Genetics, Department of Paediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Mark Tarnopolsky
- Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada
| | - Kym M Boycott
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Nicolas Dupre
- Neuroscience Axis, CHU de Québec, Université Laval, Québec City, Québec, Canada.,Department of Medicine, Faculty of Medicine, Université Laval, Québec City, Québec, Canada
| | - Patrick A Dion
- Department of Human Genetics, McGill University, Montréal, Québec, Canada.,The Neuro (Montreal Neurological Institute-Hospital), McGill University, Montréal, Québec, Canada.,Department of Neurology and Neurosurgery, McGill University, Montréal, Québec, Canada
| | - Oksana Suchowersky
- Departments of Medicine (Neurology) and Medical Genetics, University of Alberta, Edmonton, Alberta, Canada
| | - Jean-Francois Trempe
- Department of Pharmacology & Therapeutics, McGill University, Montréal, Québec, Canada.,Centre de Recherche en Biologie Structurale, McGill University, Montréal, Québec, Canada
| | - Guy A Rouleau
- Department of Human Genetics, McGill University, Montréal, Québec, Canada.,The Neuro (Montreal Neurological Institute-Hospital), McGill University, Montréal, Québec, Canada.,Department of Neurology and Neurosurgery, McGill University, Montréal, Québec, Canada
| | - Ziv Gan-Or
- Department of Human Genetics, McGill University, Montréal, Québec, Canada.,The Neuro (Montreal Neurological Institute-Hospital), McGill University, Montréal, Québec, Canada.,Department of Neurology and Neurosurgery, McGill University, Montréal, Québec, Canada
| |
Collapse
|
11
|
Sardina F, Pisciottani A, Ferrara M, Valente D, Casella M, Crescenzi M, Peschiaroli A, Casali C, Soddu S, Grierson AJ, Rinaldo C. Spastin recovery in hereditary spastic paraplegia by preventing neddylation-dependent degradation. Life Sci Alliance 2020; 3:3/12/e202000799. [PMID: 33106322 PMCID: PMC7652396 DOI: 10.26508/lsa.202000799] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 10/14/2020] [Accepted: 10/14/2020] [Indexed: 01/11/2023] Open
Abstract
Hereditary Spastic Paraplegia (HSP) is a neurodegenerative disease most commonly caused by autosomal dominant mutations in the SPG4 gene encoding the microtubule-severing protein spastin. We hypothesise that SPG4-HSP is attributable to reduced spastin function because of haploinsufficiency; thus, therapeutic approaches which elevate levels of the wild-type spastin allele may be an effective therapy. However, until now, how spastin levels are regulated is largely unknown. Here, we show that the kinase HIPK2 regulates spastin protein levels in proliferating cells, in differentiated neurons and in vivo. Our work reveals that HIPK2-mediated phosphorylation of spastin at S268 inhibits spastin K48-poly-ubiquitination at K554 and prevents its neddylation-dependent proteasomal degradation. In a spastin RNAi neuronal cell model, overexpression of HIPK2, or inhibition of neddylation, restores spastin levels and rescues neurite defects. Notably, we demonstrate that spastin levels can be restored pharmacologically by inhibiting its neddylation-mediated degradation in neurons derived from a spastin mouse model of HSP and in patient-derived cells, thus revealing novel therapeutic targets for the treatment of SPG4-HSP.
Collapse
Affiliation(s)
- Francesca Sardina
- Institute of Molecular Biology and Pathology (IBPM), National Research Council (CNR), c/o Sapienza University, Rome, Italy
| | - Alessandra Pisciottani
- Institute of Molecular Biology and Pathology (IBPM), National Research Council (CNR), c/o Sapienza University, Rome, Italy
| | - Manuela Ferrara
- Institute of Molecular Biology and Pathology (IBPM), National Research Council (CNR), c/o Sapienza University, Rome, Italy
| | - Davide Valente
- Institute of Molecular Biology and Pathology (IBPM), National Research Council (CNR), c/o Sapienza University, Rome, Italy.,Unit of Cellular Networks and Molecular Therapeutic Targets, IRCCS-Regina Elena National Cancer Institute, Rome, Italy
| | | | - Marco Crescenzi
- Core Facilities, Italian National Institute of Health, Rome, Italy
| | | | - Carlo Casali
- Department of Medico-Surgical Sciences and Biotechnologies, University of Rome Sapienza, Latina, Italy
| | - Silvia Soddu
- Unit of Cellular Networks and Molecular Therapeutic Targets, IRCCS-Regina Elena National Cancer Institute, Rome, Italy
| | - Andrew J Grierson
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK
| | - Cinzia Rinaldo
- Institute of Molecular Biology and Pathology (IBPM), National Research Council (CNR), c/o Sapienza University, Rome, Italy .,Unit of Cellular Networks and Molecular Therapeutic Targets, IRCCS-Regina Elena National Cancer Institute, Rome, Italy
| |
Collapse
|
12
|
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: 21] [Impact Index Per Article: 5.3] [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
| |
Collapse
|
13
|
Genetic and Clinical Profile of Chinese Patients with Autosomal Dominant Spastic Paraplegia. Mol Diagn Ther 2019; 23:781-789. [DOI: 10.1007/s40291-019-00426-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
14
|
Parodi L, Fenu S, Barbier M, Banneau G, Duyckaerts C, Tezenas du Montcel S, Monin ML, Ait Said S, Guegan J, Tallaksen CME, Sablonniere B, Brice A, Stevanin G, Depienne C, Durr A. Spastic paraplegia due to SPAST mutations is modified by the underlying mutation and sex. Brain 2019; 141:3331-3342. [PMID: 30476002 DOI: 10.1093/brain/awy285] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 09/28/2018] [Indexed: 12/15/2022] Open
Abstract
Hereditary spastic paraplegias (HSPs) are rare neurological disorders caused by progressive distal degeneration of the corticospinal tracts. Among the 79 loci and 65 spastic paraplegia genes (SPGs) involved in HSPs, mutations in SPAST, which encodes spastin, responsible for SPG4, are the most frequent cause of both familial and sporadic HSP. SPG4 is characterized by a clinically pure phenotype associated with restricted involvement of the corticospinal tracts and posterior columns of the spinal cord. It is rarely associated with additional neurological signs. However, both age of onset and severity of the disorder are extremely variable. Such variability is both intra- and inter-familial and may suggest incomplete penetrance, with some patients carrying mutations remaining asymptomatic for their entire life. We analysed a cohort of 842 patients with SPG4-HSP to assess genotype-phenotype correlations. Most patients were French (89%) and had a family history of SPG4-HSP (75%). Age at onset was characterized by a bimodal distribution, with high inter-familial and intra-familial variability, especially concerning first-degree relatives. Penetrance of the disorder was 0.9, complete after 70 years of age. Penetrance was lower in females (0.88 versus 0.94 in males, P = 0.01), despite a more diffuse phenotype with more frequent upper limb involvement. Seventy-seven per cent of pathogenic mutations (missense, frameshift, splice site, nonsense, and deletions) were located in the AAA cassette of spastin, impairing its microtubule-severing activity. A comparison of the missense and truncating mutations revealed a significantly lower age at onset for patients carrying missense mutations than those carrying truncating mutations, explaining the bimodal distribution of the age at onset. The age at onset for patients carrying missense mutations was often before 10 years, sometimes associated with intellectual deficiency. Neuropathological examination of a single case showed degeneration of the spinocerebellar and spinocortical tracts, as well as the posterior columns. However, there were numerous small-diameter processes among unusually large myelinated fibres in the corticospinal tract, suggesting marked regeneration. In conclusion, this large cohort of 842 individuals allowed us to identify a significantly younger age at onset in missense mutation carriers and lower penetrance in females, despite a more severe disorder. Neuropathology in one case showed numerous small fibres suggesting regeneration.
Collapse
Affiliation(s)
- Livia Parodi
- Institut du Cerveau et de la Moelle épinière (ICM), INSERM, CNRS, Assistance Publique-Hôpitaux de Paris (AP-HP), Sorbonne Université, Pitié-Salpêtrière University Hospital, Paris, France
| | - Silvia Fenu
- Institut du Cerveau et de la Moelle épinière (ICM), INSERM, CNRS, Assistance Publique-Hôpitaux de Paris (AP-HP), Sorbonne Université, Pitié-Salpêtrière University Hospital, Paris, France
| | - Mathieu Barbier
- Institut du Cerveau et de la Moelle épinière (ICM), INSERM, CNRS, Assistance Publique-Hôpitaux de Paris (AP-HP), Sorbonne Université, Pitié-Salpêtrière University Hospital, Paris, France
| | - Guillaume Banneau
- Institut du Cerveau et de la Moelle épinière (ICM), INSERM, CNRS, Assistance Publique-Hôpitaux de Paris (AP-HP), Sorbonne Université, Pitié-Salpêtrière University Hospital, Paris, France
| | - Charles Duyckaerts
- Institut du Cerveau et de la Moelle épinière (ICM), INSERM, CNRS, Assistance Publique-Hôpitaux de Paris (AP-HP), Sorbonne Université, Pitié-Salpêtrière University Hospital, Paris, France.,Raymond Escourolle Department of Neuropathology, Pitié-Salpêtrière University Hospital, Paris, France
| | - Sophie Tezenas du Montcel
- Assistance Publique-Hôpitaux de Paris (AP-HP), Pitié-Salpêtrière University Hospital, Biostatistics and Medical Informatics Unit and Clinical Research Unit, Paris, France.,Sorbonne Universités, UMR S1136, Institut Pierre Louis d'Epidémiologie et de Santé Publique, Paris, France
| | - Marie-Lorraine Monin
- Institut du Cerveau et de la Moelle épinière (ICM), INSERM, CNRS, Assistance Publique-Hôpitaux de Paris (AP-HP), Sorbonne Université, Pitié-Salpêtrière University Hospital, Paris, France
| | - Samia Ait Said
- Institut du Cerveau et de la Moelle épinière (ICM), INSERM, CNRS, Assistance Publique-Hôpitaux de Paris (AP-HP), Sorbonne Université, Pitié-Salpêtrière University Hospital, Paris, France
| | - Justine Guegan
- Institut du Cerveau et de la Moelle épinière (ICM), INSERM, CNRS, Assistance Publique-Hôpitaux de Paris (AP-HP), Sorbonne Université, Pitié-Salpêtrière University Hospital, Paris, France
| | - Chantal M E Tallaksen
- Institut du Cerveau et de la Moelle épinière (ICM), INSERM, CNRS, Assistance Publique-Hôpitaux de Paris (AP-HP), Sorbonne Université, Pitié-Salpêtrière University Hospital, Paris, France.,Department of Neurology, Oslo University Hospital, Oslo, Norway.,Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Bertrand Sablonniere
- Lille University, Inserm, CHU Lille, UMR-S 1172 - JPArc - Centre de Recherche Jean-Pierre AUBERT Neurosciences et Cancer, Lille, France.,CHU Lille, Institut de Biochimie et Biologie Moléculaire, Centre de Biologie Pathologie et Génétique, Lille, France
| | - Alexis Brice
- Institut du Cerveau et de la Moelle épinière (ICM), INSERM, CNRS, Assistance Publique-Hôpitaux de Paris (AP-HP), Sorbonne Université, Pitié-Salpêtrière University Hospital, Paris, France
| | - Giovanni Stevanin
- Institut du Cerveau et de la Moelle épinière (ICM), INSERM, CNRS, Assistance Publique-Hôpitaux de Paris (AP-HP), Sorbonne Université, Pitié-Salpêtrière University Hospital, Paris, France.,Ecole Pratique des Hautes Etudes (EPHE), Paris Sciences et Lettres (PSL) Research Univeristy, Neurogenetics Group, Paris, France
| | - Christel Depienne
- Institut du Cerveau et de la Moelle épinière (ICM), INSERM, CNRS, Assistance Publique-Hôpitaux de Paris (AP-HP), Sorbonne Université, Pitié-Salpêtrière University Hospital, Paris, France.,Institut für Humangenetik, Universitätsklinikum Essen, Essen, Germany
| | - Alexandra Durr
- Institut du Cerveau et de la Moelle épinière (ICM), INSERM, CNRS, Assistance Publique-Hôpitaux de Paris (AP-HP), Sorbonne Université, Pitié-Salpêtrière University Hospital, Paris, France
| | | |
Collapse
|
15
|
Newton T, Allison R, Edgar JR, Lumb JH, Rodger CE, Manna PT, Rizo T, Kohl Z, Nygren AOH, Arning L, Schüle R, Depienne C, Goldberg L, Frahm C, Stevanin G, Durr A, Schöls L, Winner B, Beetz C, Reid E. Mechanistic basis of an epistatic interaction reducing age at onset in hereditary spastic paraplegia. Brain 2019; 141:1286-1299. [PMID: 29481671 PMCID: PMC5917785 DOI: 10.1093/brain/awy034] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 01/04/2018] [Indexed: 12/20/2022] Open
Abstract
Many genetic neurological disorders exhibit variable expression within affected families, often exemplified by variations in disease age at onset. Epistatic effects (i.e. effects of modifier genes on the disease gene) may underlie this variation, but the mechanistic basis for such epistatic interactions is rarely understood. Here we report a novel epistatic interaction between SPAST and the contiguous gene DPY30, which modifies age at onset in hereditary spastic paraplegia, a genetic axonopathy. We found that patients with hereditary spastic paraplegia caused by genomic deletions of SPAST that extended into DPY30 had a significantly younger age at onset. We show that, like spastin, the protein encoded by SPAST, the DPY30 protein controls endosomal tubule fission, traffic of mannose 6-phosphate receptors from endosomes to the Golgi, and lysosomal ultrastructural morphology. We propose that additive effects on this pathway explain the reduced age at onset of hereditary spastic paraplegia in patients who are haploinsufficient for both genes.
Collapse
Affiliation(s)
- Timothy Newton
- Department of Medical Genetics and Cambridge Institute for Medical Research, University of Cambridge, UK
| | - Rachel Allison
- Department of Medical Genetics and Cambridge Institute for Medical Research, University of Cambridge, UK
| | - James R Edgar
- Department of Clinical Biochemistry and Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
| | - Jennifer H Lumb
- Department of Medical Genetics and Cambridge Institute for Medical Research, University of Cambridge, UK
| | - Catherine E Rodger
- Department of Medical Genetics and Cambridge Institute for Medical Research, University of Cambridge, UK
| | - Paul T Manna
- Department of Clinical Biochemistry and Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
| | - Tania Rizo
- Department of Stem Cell Biology, Friedrich-Alexander University Erlangen-Nuernberg (FAU), Erlangen, Germany
| | - Zacharias Kohl
- Department of Molecular Neurology, Friedrich-Alexander University Erlangen-Nuernberg (FAU), Erlangen, Germany
| | | | - Larissa Arning
- Department of Human Genetics, Ruhr-University, Bochum, Germany
| | - Rebecca Schüle
- Center for Neurology and Hertie Institute for Clinical Brain Research, Eberhard-Karls-University, 72076 Tübingen, Germany.,German Center of Neurodegenerative Diseases (DZNE), 72076 Tübingen, Germany
| | - Christel Depienne
- ICM Brain and Spine Institute, INSERM U1127, CNRS UMR7225, Sorbonne Universites, UPMC Univ Paris VI UMR_S1127, Paris, France.,APHP, Genetic Department, Pitie-Salpêtrière University Hospital, Paris, France
| | - Lisa Goldberg
- Department of Clinical Chemistry and Laboratory Diagnostics, Jena University Hospital, Jena, Germany
| | - Christiane Frahm
- Hans Berger Department of Neurology, Jena University Hospital, Jena, Germany
| | - Giovanni Stevanin
- ICM Brain and Spine Institute, INSERM U1127, CNRS UMR7225, Sorbonne Universites, UPMC Univ Paris VI UMR_S1127, Paris, France.,APHP, Genetic Department, Pitie-Salpêtrière University Hospital, Paris, France.,Ecole Pratique des Hautes Etudes, PSL Research University, Paris, France
| | - Alexandra Durr
- ICM Brain and Spine Institute, INSERM U1127, CNRS UMR7225, Sorbonne Universites, UPMC Univ Paris VI UMR_S1127, Paris, France.,APHP, Genetic Department, Pitie-Salpêtrière University Hospital, Paris, France
| | - Ludger Schöls
- Center for Neurology and Hertie Institute for Clinical Brain Research, Eberhard-Karls-University, 72076 Tübingen, Germany.,German Center of Neurodegenerative Diseases (DZNE), 72076 Tübingen, Germany
| | - Beate Winner
- Department of Molecular Neurology, Friedrich-Alexander University Erlangen-Nuernberg (FAU), Erlangen, Germany
| | - Christian Beetz
- Department of Clinical Chemistry and Laboratory Diagnostics, Jena University Hospital, Jena, Germany
| | - Evan Reid
- Department of Medical Genetics and Cambridge Institute for Medical Research, University of Cambridge, UK
| |
Collapse
|
16
|
Yang J, Seo JY, Lee KW, Park HM. Novel Pathogenic Variant of SPAST (c.1413+4A>G) in a Patient with Hereditary Spastic Paraplegia. J Clin Neurol 2019; 15:120-121. [PMID: 30375765 PMCID: PMC6325369 DOI: 10.3988/jcn.2019.15.1.120] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 08/05/2018] [Accepted: 08/07/2018] [Indexed: 12/02/2022] Open
Affiliation(s)
- Jiwon Yang
- Department of Neurology, Gil Medical Center, Gachon University College of Medicine, Incheon, Korea
| | - Ja Young Seo
- Department of Laboratory Medicine, Gil Medical Center, Gachon University College of Medicine, Incheon, Korea
| | - Kwang Woo Lee
- Department of Neurology, Gil Medical Center, Gachon University College of Medicine, Incheon, Korea
| | - Hyeon Mi Park
- Department of Neurology, Gil Medical Center, Gachon University College of Medicine, Incheon, Korea.
| |
Collapse
|
17
|
Bis-Brewer DM, Züchner S. Perspectives on the Genomics of HSP Beyond Mendelian Inheritance. Front Neurol 2018; 9:958. [PMID: 30534106 PMCID: PMC6275194 DOI: 10.3389/fneur.2018.00958] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2018] [Accepted: 10/25/2018] [Indexed: 12/12/2022] Open
Abstract
Hereditary Spastic Paraplegia is an extraordinarily heterogeneous disease caused by over 50 Mendelian genes. Recent applications of next-generation sequencing, large scale data analysis, and data sharing/matchmaking, have discovered a quickly expanding set of additional HSP genes. Since most recently discovered HSP genes are rare causes of the disease, there is a growing concern of a persisting diagnostic gap, estimated at 30-40%, and even higher for sporadic cases. This missing heritability may not be fully closed by classic Mendelian mutations in protein coding genes. Here we show strategies and published examples of broadening areas of attention for Mendelian and non-Mendelian causes of HSP. We suggest a more inclusive perspective on the potential final architecture of HSP genomics. Efforts to narrow the heritability gap will ultimately lead to more precise and comprehensive genetic diagnoses, which is the starting point for emerging, highly specific gene therapies.
Collapse
Affiliation(s)
- Dana M. Bis-Brewer
- Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami Miller School of Medicine, Miami, FL, United States
- John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Stephan Züchner
- Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami Miller School of Medicine, Miami, FL, United States
- John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, United States
| |
Collapse
|
18
|
Beetz C, Khundadze M, Goldberg LV, Hübner CA. Erbliche spastische Spinalparalysen: aktuelle Erkenntnisse und Entwicklungen. MED GENET-BERLIN 2018. [DOI: 10.1007/s11825-018-0196-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Zusammenfassung
Die erblichen spastischen Spinalparalysen („hereditary spastic paraplegias“, HSPs) sind Bewegungsstörungen, die aus der Degeneration der Axone oberer Motoneuronen resultieren. Sie sind klinisch und genetisch sehr heterogen. Der vorliegende Übersichtsartikel fasst aktuelle Strategien zur genetischen Diagnostik der HSPs zusammen, erörtert mögliche Mutationsmechanismen, diskutiert Erklärungen für die klinische Variabilität innerhalb ausgewählter Formen und verweist auf noch ungeklärte und zum Teil wenig beachtete Phänomene. Außerdem wird die Notwendigkeit eines tieferen Verständnisses der zellulären und molekularen Mechanismen für die Entwicklung neuer Therapien dargestellt.
Collapse
Affiliation(s)
- Christian Beetz
- Aff1 0000 0000 8517 6224 grid.275559.9 Institut für Klinische Chemie und Laboratoriumsdiagnostik Universitätsklinikum Jena Jena Deutschland
| | - Mukhran Khundadze
- Aff2 0000 0000 8517 6224 grid.275559.9 Institut für Humangenetik Universitätsklinikum Jena Am Klinikum 1 07747 Jena Deutschland
| | - Lisa V. Goldberg
- Aff1 0000 0000 8517 6224 grid.275559.9 Institut für Klinische Chemie und Laboratoriumsdiagnostik Universitätsklinikum Jena Jena Deutschland
| | - Christian A. Hübner
- Aff2 0000 0000 8517 6224 grid.275559.9 Institut für Humangenetik Universitätsklinikum Jena Am Klinikum 1 07747 Jena Deutschland
| |
Collapse
|
19
|
Gillespie MK, Humphreys P, McMillan HJ, Boycott KM. Association of Early-Onset Spasticity and Risk for Cognitive Impairment With Mutations at Amino Acid 499 in SPAST. J Child Neurol 2018; 33:329-332. [PMID: 29421991 DOI: 10.1177/0883073818756680] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Hereditary spastic paraplegia is a phenotypically and genetically heterogeneous group of neurodegenerative disorders characterized by lower extremity weakness and spasticity. Spastic paraplegia 4 (SPG4), caused by heterozygous mutations in the gene SPAST, typically causes a late-onset, uncomplicated form of hereditary spastic paraplegia in affected individuals. Additional clinical features in SPG4 have been reported on occasion, but no genotype-phenotype correlation has been established. Through targeted clinical testing, we identified 2 unrelated female patients with the same de novo p.Arg499His mutation in SPAST. Both patients presented with early-onset spasticity resulting in delayed motor milestones, which led to a diagnosis of cerebral palsy in one child and tethered cord in the other. Review of the literature identified several patients with mutations at amino acid 499 and early-onset symptoms associated with a risk of cognitive impairment. Early and accurate diagnosis of children with early-onset spasticity is important for informed prognosis and genetic counselling.
Collapse
Affiliation(s)
- Meredith K Gillespie
- 1 Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, ON, Canada
| | - Peter Humphreys
- 1 Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, ON, Canada
- 2 Division of Neurology, Department of Pediatrics, Children's Hospital of Eastern Ontario, Ottawa, ON, Canada
| | - Hugh J McMillan
- 1 Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, ON, Canada
- 2 Division of Neurology, Department of Pediatrics, Children's Hospital of Eastern Ontario, Ottawa, ON, Canada
| | - Kym M Boycott
- 1 Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, ON, Canada
- 3 Department of Genetics, Children's Hospital of Eastern Ontario, Ottawa, ON, Canada
| |
Collapse
|
20
|
Bhartiya D, Kumar A, Kaur J, Kumari S, Sharma AK, Sinha DN, Singh H, Mehrotra R. In-silico study of toxicokinetics and disease association of chemicals present in smokeless tobacco products. Regul Toxicol Pharmacol 2018; 95:8-16. [PMID: 29505798 DOI: 10.1016/j.yrtph.2018.03.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 01/11/2018] [Accepted: 03/01/2018] [Indexed: 12/24/2022]
Abstract
Smokeless tobacco (SLT) products are consumed by millions of people in over 130 countries around the world. Consumption of SLT has been estimated to cause a number of diseases accounting to more than 0.65 million deaths per year. There is sufficient epidemiological evidence on the association of SLT products with nicotine addiction, cancers of oral cavity and digestive systems but there is a lack of understanding of the role of toxic chemicals in these diseases. We provide the first comprehensive in-silico analysis of chemical compounds present in different SLT products used worldwide. Many of these compounds are found to have good absorption, solubility and permeability along with mutagenic and toxic properties. They are also found to target more than 350 human proteins involved in a plethora of human biological processes and pathways. Along with all the previously known diseases, the present study has identified the association of compounds of SLT products with a number of unknown diseases like neurodegenerative, immune and cardiac diseases (Left ventricular non compaction, dilated cardiomyopathy etc). These findings indicate far-reaching impact of SLT products on human health than already known which needs further validations using epidemiological, in-vitro and in-vivo methodologies. Thus, this study will provide one stop information for the policy makers in development of regulatory policies on toxic contents of SLT products.
Collapse
Affiliation(s)
- Deeksha Bhartiya
- Data Management Laboratory, National Institute of Cancer Prevention and Research, Noida, Uttar Pradesh 201301, India
| | - Amit Kumar
- Data Management Laboratory, National Institute of Cancer Prevention and Research, Noida, Uttar Pradesh 201301, India
| | - Jasmine Kaur
- Informatics, Systems and Research Management, Indian Council of Medical Research, New Delhi 110029, India
| | - Suchitra Kumari
- Data Management Laboratory, National Institute of Cancer Prevention and Research, Noida, Uttar Pradesh 201301, India
| | - Amitesh Kumar Sharma
- Informatics, Systems and Research Management, Indian Council of Medical Research, New Delhi 110029, India
| | - Dhirendra N Sinha
- WHO FCTC Global Knowledge Hub of Smokeless Tobacco, National Institute of Cancer Prevention and Research, Noida, Uttar Pradesh 201301, India
| | - Harpreet Singh
- Informatics, Systems and Research Management, Indian Council of Medical Research, New Delhi 110029, India.
| | - Ravi Mehrotra
- WHO FCTC Global Knowledge Hub of Smokeless Tobacco, National Institute of Cancer Prevention and Research, Noida, Uttar Pradesh 201301, India; National Institute of Cancer Prevention and Research, Noida, Uttar Pradesh 201301, India
| |
Collapse
|
21
|
Parodi L, Fenu S, Stevanin G, Durr A. Hereditary spastic paraplegia: More than an upper motor neuron disease. Rev Neurol (Paris) 2017; 173:352-360. [DOI: 10.1016/j.neurol.2017.03.034] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 03/31/2017] [Indexed: 12/11/2022]
|
22
|
Mészárosová AU, Putzová M, Čermáková M, Vávrová D, Doležalová K, Smetanová I, Stejskal D, Beetz C, Seeman P. SPAST mutation spectrum and familial occurrence among Czech patients with pure hereditary spastic paraplegia. J Hum Genet 2016; 61:845-850. [PMID: 27334366 DOI: 10.1038/jhg.2016.73] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 04/25/2016] [Accepted: 05/17/2016] [Indexed: 11/09/2022]
Abstract
The SPAST gene has a major role in hereditary spastic paraplegias (HSPs). This is the first report mapping characteristics of the SPAST gene in a large cohort of Czech HSP patients. All 17 coding exons of the SPAST gene were Sanger sequenced in 327 patients from 263 independent families with suspected uncomplicated HSP. The selected 126 independent patients, without mutation in the SPAST gene after Sanger sequencing, were subsequently tested by Multiplex Ligation-dependent Probe Amplification (MLPA) assay for large deletions or copy number variations affecting the SPAST gene. Among the 263 independent patients, 35 different, small mutations in 44 patients were found. Twenty-one mutations are novel with the majority of frameshift mutations. Seven mutations were found in more than one family. The age at onset ranged between preschool childhood and the fifth decade with inter- and intra-familiar differences. SPAST small mutations were detected in 16.7% (44/263) of independent tested patients. Mutations in the SPAST gene were found more frequently in familial cases (with affected relatives). Mutation were found in 31.9% (29/91 familial tested) in the familial patient group, whereas in the sporadic patient group, mutations were found in only 4.7% of cases (5/106 sporadic cases). Among SPAST-positive patients, 65.9% (29/44) were familial but only 11.4% (5/44) were sporadic. MLPA testing revealed four large deletions in four independent patients, all in familial-positive cases. Mutations in the SPAST gene are 5.8 × more frequent in familial than in sporadic cases. Large deletions were found only in familial patients. Diagnostic testing of the SPAST gene is useful only in positive family history patients not in sporadic cases.
Collapse
Affiliation(s)
- Anna Uhrová Mészárosová
- DNA Laboratory, Department of Child Neurology, Charles University Second Medical School and University Hospital Motol, Prague, Czech Republic
| | - Martina Putzová
- Centre for Medical Genetics and Reproductive Medicine GENNET, Prague, Czech Republic
| | - Marie Čermáková
- Centre for Medical Genetics and Reproductive Medicine GENNET, Prague, Czech Republic
| | - Dagmar Vávrová
- Centre for Medical Genetics and Reproductive Medicine GENNET, Prague, Czech Republic
| | - Kateřina Doležalová
- Centre for Medical Genetics and Reproductive Medicine GENNET, Prague, Czech Republic
| | - Irena Smetanová
- Centre for Medical Genetics and Reproductive Medicine GENNET, Prague, Czech Republic
| | - David Stejskal
- Centre for Medical Genetics and Reproductive Medicine GENNET, Prague, Czech Republic
| | - Christian Beetz
- Department of Clinical Chemistry and Laboratory Medicine, Universitatsklinikum, Jena, Germany
| | - Pavel Seeman
- DNA Laboratory, Department of Child Neurology, Charles University Second Medical School and University Hospital Motol, Prague, Czech Republic.,Centre for Medical Genetics and Reproductive Medicine GENNET, Prague, Czech Republic
| |
Collapse
|
23
|
Martinuzzi A, Montanaro D, Vavla M, Paparella G, Bonanni P, Musumeci O, Brighina E, Hlavata H, Rossi G, Aghakhanyan G, Martino N, Baratto A, D’Angelo MG, Peruch F, Fantin M, Arnoldi A, Citterio A, Vantaggiato C, Rizzo V, Toscano A, Bresolin N, Bassi MT. Clinical and Paraclinical Indicators of Motor System Impairment in Hereditary Spastic Paraplegia: A Pilot Study. PLoS One 2016; 11:e0153283. [PMID: 27077743 PMCID: PMC4831837 DOI: 10.1371/journal.pone.0153283] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 03/25/2016] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Hereditary spastic paraplegias (HSP) are a composite and genetically heterogeneous group of conditions mainly expressed by the impairment of the central motor system ("pure" forms). The involvement of other components of the central nervous system or of other systems is described in the "complicate" forms. The definition of an investigation protocol capable, by assembling clinical and paraclinical indicators to fully represent the extent of the motor system impairment, would help both the clinical handling of these conditions and contribute to our understanding of their pathogenesis. METHODS We applied a clinical and paraclinical protocol which included tools exploring motor and non motor functioning, neurophysiology and MRI to a composite cohort of 70 molecularly defined HSP patients aged 3 to 65, to define for each indicator its significance in detailing the presence and the severity of the pathology. RESULTS Clinically increased deep tendon reflexes and lower limb (LL) weakness are constant findings in all patients. The "complicated" forms are characterized by peripheral motor impairment, cognitive and cerebellar involvement. The Spastic Paraplegia Rating Scale efficiently reflects the severity of functional problems and correlates with disease duration. Neurophysiology consistently documents the impairment of the central motor pathway to the LLs. Nevertheless, the upper extremities and sensory system involvement is a frequent finding. MRI diffusion tensor imaging (DTI) highlighted a significant alteration of FA and MD. Combining the sampling of the various portion of the cortico-spinal tract (CST) DTI consistently discriminated patients from controls. CONCLUSION We propose a graded clinical and paraclinical protocol for HSP phenotype definition, indicating for each tool the discriminative and descriptive capacity. Our protocol applied to 9 different forms of HSP showed that the functional impairment often extends beyond the CST. The novel DTI approach may add significant elements in disease recognition, staging and mapping.
Collapse
Affiliation(s)
- Andrea Martinuzzi
- IRCCS E. Medea, Polo Regionale di Conegliano, Conegliano (TV), Italy
- * E-mail:
| | - Domenico Montanaro
- Fondazione CNR/Regione Toscana G. Monasterio, Unit of Neuroradiology, Pisa, Italy
| | - Marinela Vavla
- IRCCS E. Medea, Polo Regionale di Conegliano, Conegliano (TV), Italy
| | | | - Paolo Bonanni
- IRCCS E. Medea, Polo Regionale di Conegliano, Conegliano (TV), Italy
| | - Olimpia Musumeci
- University of Messina, Department of Neurosciences, Messina, Italy
| | - Erika Brighina
- IRCCS E. Medea, Neurorehabilitation Department, Bosisio Parini (LC), Italy
| | - Hana Hlavata
- Fondazione CNR/Regione Toscana G. Monasterio, Unit of Neuroradiology, Pisa, Italy
| | - Giuseppe Rossi
- Institute of Clinical Physiology, National Council of Research, Unit of Epidemiology and Biostatistics, Pisa, Italy
| | - Gayane Aghakhanyan
- Fondazione CNR/Regione Toscana G. Monasterio, Unit of Neuroradiology, Pisa, Italy
| | - Nicola Martino
- ULSS 7-Pieve di Soligo, Department of Imaging, Conegliano (TV), Italy
| | | | | | - Francesca Peruch
- IRCCS E. Medea, Polo Regionale di Conegliano, Conegliano (TV), Italy
| | - Marianna Fantin
- IRCCS E. Medea, Polo Regionale di Conegliano, Conegliano (TV), Italy
| | - Alessia Arnoldi
- IRCCS E. Medea, Laboratory of Molecular Biology, Bosisio Parini (LC), Italy
| | - Andrea Citterio
- IRCCS E. Medea, Laboratory of Molecular Biology, Bosisio Parini (LC), Italy
| | - Chiara Vantaggiato
- IRCCS E. Medea, Laboratory of Molecular Biology, Bosisio Parini (LC), Italy
| | - Vincenzo Rizzo
- University of Messina, Department of Neurosciences, Messina, Italy
| | - Antonio Toscano
- University of Messina, Department of Neurosciences, Messina, Italy
| | - Nereo Bresolin
- IRCCS Fondazione Policlinico, University of Milano, Department of Neuroscience, Milano, Italy
| | - Maria Teresa Bassi
- IRCCS E. Medea, Laboratory of Molecular Biology, Bosisio Parini (LC), Italy
| |
Collapse
|
24
|
Coignion C, Banneau G, Goizet C. Paraplegie spastiche ereditarie. Neurologia 2016. [DOI: 10.1016/s1634-7072(16)77572-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
|
25
|
Genetic background of the hereditary spastic paraplegia phenotypes in Hungary - An analysis of 58 probands. J Neurol Sci 2016; 364:116-21. [PMID: 27084228 DOI: 10.1016/j.jns.2016.03.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Revised: 03/08/2016] [Accepted: 03/10/2016] [Indexed: 01/01/2023]
Abstract
BACKGROUND Hereditary spastic paraplegias (HSPs) are a clinically and genetically heterogeneous group of neurodegenerative diseases with progressive lower limb spasticity and weakness. The aim of this study is to determine the frequency of different SPG mutations in Hungarian patients, and to provide further genotype-phenotype correlations for the known HSP causing genes. METHODS We carried out genetic testing for 58 probands with clinical characteristics of HSP. For historical reasons, three different approaches were followed in different patients: 1) Sanger sequencing of ATL1 and SPAST genes, 2) whole exome, and 3) targeted panel sequencing by next generation sequencing. RESULTS Genetic diagnosis was established for 20 probands (34.5%). We detected nine previously unreported mutations with high confidence for pathogenicity. The most frequently affected gene was SPAST with pathogenic or likely pathogenic mutations in 10 probands. The most frequently detected variant in our cohort was the SPG7 p.Leu78*, observed in four probands. Altogether five probands were diagnosed with SPG7. Additional mutations were detected in SPG11, ATL1, NIPA1, and ABCD1. CONCLUSION This is the first comprehensive genetic epidemiological study of patients with HSP in Hungary. Next generation sequencing improved the yield of genetic diagnostics in this disease group even when the phenotype was atypical. However, considering the frequency of the HSP-causing gene defects, SPG4, the most common form of the disease, should be tested first to be cost effective in this economic region.
Collapse
|
26
|
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: 117] [Impact Index Per Article: 13.0] [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.
Collapse
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
| |
Collapse
|
27
|
Delving into the complexity of hereditary spastic paraplegias: how unexpected phenotypes and inheritance modes are revolutionizing their nosology. Hum Genet 2015; 134:511-38. [PMID: 25758904 PMCID: PMC4424374 DOI: 10.1007/s00439-015-1536-7] [Citation(s) in RCA: 103] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Accepted: 02/23/2015] [Indexed: 12/11/2022]
Abstract
Hereditary spastic paraplegias (HSP) are rare neurodegenerative diseases sharing the degeneration of the corticospinal tracts as the main pathological characteristic. They are considered one of the most heterogeneous neurological disorders. All modes of inheritance have been described for the 84 different loci and 67 known causative genes implicated up to now. Recent advances in molecular genetics have revealed clinico-genetic heterogeneity of these disorders including their clinical and genetic overlap with other diseases of the nervous system. The systematic analysis of a large set of genes, including exome sequencing, is unmasking unusual phenotypes or inheritance modes associated with mutations in HSP genes and related genes involved in various neurological diseases. A new nosology may emerge after integration and understanding of these new data to replace the current classification. Collectively, functions of the known genes implicate the disturbance of intracellular membrane dynamics and trafficking as the consequence of alterations of cytoskeletal dynamics, lipid metabolism and organelle structures, which represent in fact a relatively small number of cellular processes that could help to find common curative approaches, which are still lacking.
Collapse
|
28
|
C9orf72 hexanucleotide repeat expansion analysis in Chinese spastic paraplegia patients. J Neurol Sci 2014; 347:104-6. [DOI: 10.1016/j.jns.2014.09.028] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 09/15/2014] [Accepted: 09/17/2014] [Indexed: 12/13/2022]
|
29
|
Luo Y, Chen C, Zhan Z, Wang Y, Du J, Hu Z, Liao X, Zhao G, Wang J, Yan X, Jiang H, Pan Q, Xia K, Tang B, Shen L. Mutation and clinical characteristics of autosomal-dominant hereditary spastic paraplegias in China. NEURODEGENER DIS 2014; 14:176-83. [PMID: 25341883 DOI: 10.1159/000365513] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 06/24/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Hereditary spastic paraplegias constitute a heterogeneous group of inherited neurodegenerative disorders. To date, there has been no systematic mutation and clinical analysis for a large group of autosomal-dominant hereditary spastic paraplegias in China. OBJECTIVE The purpose of this study was to investigate the mutation frequencies and the clinical phenotypes of Chinese spastic paraplegia patients. METHODS Direct sequencing and a multiplex ligation-dependent probe amplification assay were applied to detect the mutations of SPAST and ATL1 in 54 autosomal-dominant hereditary spastic paraplegia probands and 66 isolated cases. Next, mutations in NIPA1, KIF5A, REEP1 and SLC33A1 were detected in the negative patients. Subsets of spastic paraplegia patients were genotyped for the modifying variants. Further, detailed clinical data regarding the genetically diagnosed families were analysed. RESULTS Altogether, 27 families were diagnosed as SPG4, 3 as SPG3A and 1 as SPG6. No mutations in KIF5A, REEP1 or SLC33A1 were found; 9 SPAST mutations were novel. There was no p.S44L or p.P45Q variant in SPAST and no p.G563A variant in HSPD1 in either the 120 spastic paraplegia patients or the 500 controls. There was a remarkable clinical difference between the SPG4 and non-SPG4 patients and even between genders among the SPG4 patients. Non-penetrance and remarkable gender difference were observed in some SPG4 and SPG3A families. CONCLUSIONS Our data confirm that hereditary spastic paraplegias in China represent a heterogeneous group of genetic neurodegenerative disorders in autosomal-dominant and apparently sporadic forms. Novel genotype-phenotype correlations were established. © 2014 S. Karger AG, Basel.
Collapse
Affiliation(s)
- Yingying Luo
- Department of Neurology, Xianga Hospital of Central South University, Changsha, China
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Baxter SL, Allard DE, Crowl C, Sherwood NT. Cold temperature improves mobility and survival in Drosophila models of autosomal-dominant hereditary spastic paraplegia (AD-HSP). Dis Model Mech 2014; 7:1005-12. [PMID: 24906373 PMCID: PMC4107329 DOI: 10.1242/dmm.013987] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Autosomal-dominant hereditary spastic paraplegia (AD-HSP) is a crippling neurodegenerative disease for which effective treatment or cure remains unknown. Victims experience progressive mobility loss due to degeneration of the longest axons in the spinal cord. Over half of AD-HSP cases arise from loss-of-function mutations in spastin, which encodes a microtubule-severing AAA ATPase. In Drosophila models of AD-HSP, larvae lacking Spastin exhibit abnormal motor neuron morphology and function, and most die as pupae. Adult survivors display impaired mobility, reminiscent of the human disease. Here, we show that rearing pupae or adults at reduced temperature (18°C), compared with the standard temperature of 24°C, improves the survival and mobility of adult spastin mutants but leaves wild-type flies unaffected. Flies expressing human spastin with pathogenic mutations are similarly rescued. Additionally, larval cooling partially rescues the larval synaptic phenotype. Cooling thus alleviates known spastin phenotypes for each developmental stage at which it is administered and, notably, is effective even in mature adults. We find further that cold treatment rescues larval synaptic defects in flies with mutations in Flower (a protein with no known relation to Spastin) and mobility defects in flies lacking Kat60-L1, another microtubule-severing protein enriched in the CNS. Together, these data support the hypothesis that the beneficial effects of cold extend beyond specific alleviation of Spastin dysfunction, to at least a subset of cellular and behavioral neuronal defects. Mild hypothermia, a common neuroprotective technique in clinical treatment of acute anoxia, might thus hold additional promise as a therapeutic approach for AD-HSP and, potentially, for other neurodegenerative diseases.
Collapse
Affiliation(s)
- Sally L Baxter
- Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Denise E Allard
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA
| | | | | |
Collapse
|
31
|
Racis L, Storti E, Pugliatti M, Agnetti V, Tessa A, Santorelli FM. Novel SPAST deletion and reduced DPY30 expression in a Spastic Paraplegia type 4 kindred. BMC MEDICAL GENETICS 2014; 15:39. [PMID: 24690193 PMCID: PMC3974227 DOI: 10.1186/1471-2350-15-39] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 03/12/2014] [Indexed: 11/12/2022]
Abstract
BACKGROUND The hereditary spastic paraplegias (HSPs) are pleiomorphic disorders of motor pathway and a large number of affected genes have been discovered. Yet, mutations in SPG4/SPAST represent the most frequent molecular etiology in autosomal dominant (AD) patients and sporadic cases. We describe a large, AD-HSP Sardinian family where 5 out of several living members harbored a novel deletion affecting also the 5'UTR of SPAST and resulting in reduced expression of DPY30, the gene located upstream SPAST in a head-to-head manner. CASE PRESENTATION A 54-year-old woman manifested leg stiffness at age 39 and required a cane to walk at age 50. Neurological examination disclosed mild spasticity and weakness in the legs, hyperreflexia in all limbs, and bilateral Babinski sign. She also complained of urinary urgency, but no additional neurological symptoms or signs were detected at examination. The clinical examination of 24 additional relatives disclosed three further affected individuals, two men and one woman. In the four symptomatic patients the initial manifestations were walking abnormalities and leg stiffness with a mean age at onset (SD) of 46.75 (5.44) years (range 39-51). The mean disease duration was 13.2 (13.4) years (range 6-35), and it correlated well with clinical severity (SPRS score) (r = 0.975, p = 0.005). One patient was confined to bed and displayed knee and ankle contractures, another case needed a cane to walk, and two individuals were able to walk without aids. Interestingly, a patient had also had a miscarriage during her first pregnancy.Gene testing revealed an heterozygous deletion spanning from the 5'-UTR to intron 4 of SPAST in the affected individuals and in one clinically unaffected woman. In three affected patients, the deletion also determined low mRNA levels of SPAST and DPY30, a component of the Set1-like multiprotein histone methyltransferase complex located upstream, head-to-head with SPAST. CONCLUSION Together with data described in a Japanese family, our findings seem to suggest that genes close to spastin might be candidates in modulating the clinical phenotype. This report endorses future research on the role of neighboring genes as potential players in SPG4 disease variability.
Collapse
Affiliation(s)
- Loretta Racis
- Department of Clinical and Experimental Medicine, University of Sassari, Sassari, Italy
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Eugenia Storti
- IRCCS Stella Maris, via dei Giacinti 2, 56028 Pisa, Italy
| | - Maura Pugliatti
- Department of Clinical and Experimental Medicine, University of Sassari, Sassari, Italy
| | - Virgilio Agnetti
- Department of Clinical and Experimental Medicine, University of Sassari, Sassari, Italy
| | | | | |
Collapse
|
32
|
Denora PS, Santorelli FM, Bertini E. Hereditary spastic paraplegias: one disease for many genes, and still counting. HANDBOOK OF CLINICAL NEUROLOGY 2013; 113:1899-912. [PMID: 23622413 DOI: 10.1016/b978-0-444-59565-2.00060-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Hereditary spastic paraplegias (HSPs) are genetically heterogeneous Mendelian disorders characterized by spastic gait with stiffness and weakness in the legs and an associated plethora of neurological or extraneurological signs in "complicated" forms. Major advances have been made during the past two decades in our understanding of their molecular bases with the identification of a large number of gene loci and the cloning of a set of them. The combined genetic and clinical information obtained has permitted a new, molecularly-driven classification and an improved diagnosis of these conditions. This represents a prerequisite for better counseling in families and more appropriate therapeutic options. However, further heterogeneity is expected and new insight into the possible mechanisms anticipated.
Collapse
Affiliation(s)
- Paola S Denora
- Molecular Medicine and Unit of Neuromuscular and Neurodegenerative Diseases, IRCCS-Children's Hospital Bambino Gesù, Rome, Italy
| | | | | |
Collapse
|
33
|
Vandebona H, Kerr NP, Liang C, Sue CM. SPASTmutations in Australian patients with hereditary spastic paraplegia. Intern Med J 2012; 42:1342-7. [DOI: 10.1111/j.1445-5994.2012.02941.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Accepted: 03/30/2012] [Indexed: 01/04/2023]
Affiliation(s)
- H. Vandebona
- Department of Neurogenetics; Kolling Institute of Medical Research; University of Sydney
| | - N. P. Kerr
- Department of Neurogenetics; Kolling Institute of Medical Research; University of Sydney
| | - C. Liang
- Department of Neurology; Royal North Shore Hospital; Sydney New South Wales Australia
| | - C. M. Sue
- Department of Neurogenetics; Kolling Institute of Medical Research; University of Sydney
- Department of Neurology; Royal North Shore Hospital; Sydney New South Wales Australia
| |
Collapse
|
34
|
Clinical and genetic analysis of four Taiwanese families with autosomal dominant hereditary spastic paraplegia. J Formos Med Assoc 2012; 111:380-5. [PMID: 22817815 DOI: 10.1016/j.jfma.2011.06.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2010] [Revised: 06/28/2011] [Accepted: 06/30/2011] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND/PURPOSE Hereditary spastic paraplegias (HSPs) are clinically and genetically heterogeneous neurodegenerative disorders. Defects in the SPG4 and SPG3A genes are the two leading causes of HSPs with autosomal dominant inheritance (AD-HSPs). The purpose of this study was to investigate the clinical features and associated genetic mutations in Taiwanese families with AD-HSP. METHODS Four kindreds with AD-HSP were recruited, and clinical data were collected from the affected individuals. Genetic studies were conducted in the following order: sequence analysis of the SPG4 gene (SPAST) exons, multiplex ligation-dependent probe amplification to detect genetic rearrangements in SPAST, and sequence analysis of the SPG3A gene exons. RESULTS Four different SPAST mutations were detected, including a novel small deletion, a missense mutation, and two gross deletions involving exon 17. Although all symptomatic cases manifested as uncomplicated phenotypes, considerable intrakindred and interkindred variations in terms of age at onset, rate of progression, and severity of disease were observed. CONCLUSION Mutation patterns and phenotypic expressivity are heterogeneous in Taiwanese patients with SPG4-related HSP. Genetic rearrangements could be a significant cause of SPG4-related HSP in the Taiwanese population. Assessment of the large deletions that could present in SPAST is warranted when direct sequencing is uninformative.
Collapse
|
35
|
McCorquodale DS, Ozomaro U, Huang J, Montenegro G, Kushman A, Citrigno L, Price J, Speziani F, Pericak-Vance MA, Züchner S. Mutation screening of spastin, atlastin, and REEP1 in hereditary spastic paraplegia. Clin Genet 2011; 79:523-30. [PMID: 20718791 DOI: 10.1111/j.1399-0004.2010.01501.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Hereditary spastic paraplegia (HSP) comprises a group of clinically and genetically heterogeneous diseases that affect the upper motor neurons and their axonal projections. Over 40 chromosomal loci have been identified for autosomal dominant, recessive, and X-linked HSP. Mutations in the genes atlastin, spastin and REEP1 are estimated to account for up to 50% of autosomal-dominant HSP and currently guide the molecular diagnosis of HSP. Here, we report the mutation screening results of 120 HSP patients from North America for spastin, atlastin, and REEP1, with the latter one partially reported previously. We identified mutations in 36.7% of all tested HSP patients and describe 20 novel changes in spastin and atlastin. Our results add to a growing number of HSP disease-associated variants and confirm the high prevalence of atlastin, spastin, and REEP1 mutations in the HSP patient population.
Collapse
Affiliation(s)
- D S McCorquodale
- John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Loss of Drosophila melanogaster p21-activated kinase 3 suppresses defects in synapse structure and function caused by spastin mutations. Genetics 2011; 189:123-35. [PMID: 21705760 DOI: 10.1534/genetics.111.130831] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Microtubules are dynamic structures that must elongate, disassemble, and be cleaved into smaller pieces for proper neuronal development and function. The AAA ATPase Spastin severs microtubules along their lengths and is thought to regulate the balance between long, stable filaments and shorter fragments that seed extension or are transported. In both Drosophila and humans, loss of Spastin function results in reduction of synaptic connections and disabling motor defects. To gain insight into how spastin is regulated, we screened the Drosophila melanogaster genome for deletions that modify a spastin overexpression phenotype, eye size reduction. One suppressor region deleted p21-activated kinase 3 (pak3), which encodes a member of the Pak family of actin-regulatory enzymes, but whose in vivo function is unknown. We show that pak3 mutants have only mild synaptic defects at the larval neuromuscular junction, but exhibit a potent genetic interaction with spastin mutations. Aberrant bouton morphology, microtubule distribution, and synaptic transmission caused by spastin loss of function are all restored to wild type when pak3 is simultaneously reduced. Neuronal overexpression of pak3 induces actin-rich thin projections, suggesting that it functions in vivo to promote filopodia during presynaptic terminal arborization. pak3 therefore regulates synapse development in vivo, and when mutated, suppresses the synaptic defects that result from spastin loss.
Collapse
|
37
|
Klimpe S, Zibat A, Zechner U, Wellek B, Shoukier M, Sauter SM, Pantakani DVK, Mannan AU. Evaluating the effect of spastin splice mutations by quantitative allele-specific expression assay. Eur J Neurol 2011; 18:99-105. [PMID: 20491894 DOI: 10.1111/j.1468-1331.2010.03079.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND mutations in the SPG4/SPAST gene are the most common cause for hereditary spastic paraplegia (HSP). The splice-site mutations make a significant contribution to HSP and account for 17.4% of all types of mutations and 30.8% of point mutations in the SPAST gene. However, only few studies with limited molecular approach were conducted to investigate and decipher the role of SPAST splice-site mutations in HSP. METHODS a reverse transcriptase-polymerase chain reaction (RT-PCR) analysis and quantitative allele-specific expression assay were performed. RESULTS we have characterized the consequence of two novel splice-site mutations (c.1493 + 1G>A and c.1414-1G>A) in the SPAST gene in two different families with pure HSP. The RT-PCR analysis revealed that both spastin mutations are indeed splice-site mutations and cause skipping of exon 12. Furthermore, RT-PCR data suggested that these splice-site mutations may cause leaky splicing. By means of a quantitative allele-specific expression assay, we could confirm that both splice-site mutations cause leaky splicing, as the relative expression of the exon 12-skipped transcript was reduced (21.1 ± 3.6 compared to expected 50%). CONCLUSIONS our finding supports a "threshold-effect-model" for functional spastin in HSP. A higher level (78.8 ± 3.9%) of functional spastin than the expected ratio of 50% owing to leaky splicing might cause late age at onset of HSP. Remarkably, we could show that a quantitative allele-specific expression assay is a simple and effective tool to evaluate the role of most types of spastin splice-site mutations in HSP.
Collapse
Affiliation(s)
- S Klimpe
- Department of Neurology, University Medical Center, Johannes Gutenberg University, Mainz, Germany
| | | | | | | | | | | | | | | |
Collapse
|
38
|
Proukakis C, Moore D, Labrum R, Wood NW, Houlden H. Detection of novel mutations and review of published data suggests that hereditary spastic paraplegia caused by spastin (SPAST) mutations is found more often in males. J Neurol Sci 2011; 306:62-5. [PMID: 21546041 DOI: 10.1016/j.jns.2011.03.043] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2010] [Revised: 02/08/2011] [Accepted: 03/28/2011] [Indexed: 02/01/2023]
Abstract
BACKGROUND Hereditary spastic paraplegia (HSP) is characterised in its pure form by slowly progressive spastic paraparesis. Around 40% of autosomal dominant (AD) cases are caused by mutations in SPAST, encoding spastin. PATIENTS AND METHODS The clinical and investigation details of all patients with a SPAST mutation identified through our centre were reviewed. All published reports of SPAST mutations where the sex of patients was given were subsequently analysed in order to determine whether there is evidence of one sex being preferentially affected. RESULTS In total 22 probable pathogenic changes were detected, including 11 novel ones. One patient carried two adjacent missense mutations. The pathogenicity of a further novel missense mutation is uncertain. Most patients had a pure phenotype, although mild peripheral neuropathy was sometimes present. The total number of patients with SPAST mutations was 27, as three of the previously known mutations were present in more than one person. The excess of males over females in our population (17:10) prompted us to review all published studies where the sex of the patients was given (n=31). A significant excess of males was identified (ratio 1.29, p=0.0007). CONCLUSIONS Our results are consistent with data suggesting that SPAST mutations mostly cause a pure HSP phenotype. The excess of males in our sample and in published reports suggests that penetrance or severity may be sex-dependent, and merits further investigation as it may have important implications for counselling.
Collapse
Affiliation(s)
- Christos Proukakis
- Department of Clinical Neurosciences, University College London Institute of Neurology, Royal Free Campus, London, NW3 2PF, UK.
| | | | | | | | | |
Collapse
|
39
|
Alvarez V, Sánchez-Ferrero E, Beetz C, Díaz M, Alonso B, Corao AI, Gámez J, Esteban J, Gonzalo JF, Pascual-Pascual SI, López de Munain A, Moris G, Ribacoba R, Márquez C, Rosell J, Marín R, García-Barcina MJ, Del Castillo E, Benito C, Coto E. Mutational spectrum of the SPG4 (SPAST) and SPG3A (ATL1) genes in Spanish patients with hereditary spastic paraplegia. BMC Neurol 2010; 10:89. [PMID: 20932283 PMCID: PMC2964648 DOI: 10.1186/1471-2377-10-89] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2010] [Accepted: 10/08/2010] [Indexed: 11/10/2022] Open
Abstract
Background Hereditary Spastic Paraplegias (HSP) are characterized by progressive spasticity and weakness of the lower limbs. At least 45 loci have been identified in families with autosomal dominant (AD), autosomal recessive (AR), or X-linked hereditary patterns. Mutations in the SPAST (SPG4) and ATL1 (SPG3A) genes would account for about 50% of the ADHSP cases. Methods We defined the SPAST and ATL1 mutational spectrum in a total of 370 unrelated HSP index cases from Spain (83% with a pure phenotype). Results We found 50 SPAST mutations (including two large deletions) in 54 patients and 7 ATL1 mutations in 11 patients. A total of 33 of the SPAST and 3 of the ATL1 were new mutations. A total of 141 (31%) were familial cases, and we found a higher frequency of mutation carriers among these compared to apparently sporadic cases (38% vs. 5%). Five of the SPAST mutations were predicted to affect the pre-mRNA splicing, and in 4 of them we demonstrated this effect at the cDNA level. In addition to large deletions, splicing, frameshifting, and missense mutations, we also found a nucleotide change in the stop codon that would result in a larger ORF. Conclusions In a large cohort of Spanish patients with spastic paraplegia, SPAST and ATL1 mutations were found in 15% of the cases. These mutations were more frequent in familial cases (compared to sporadic), and were associated with heterogeneous clinical manifestations.
Collapse
Affiliation(s)
- Victoria Alvarez
- Laboratory of Molecular Genetics -Genetic Unit, Hospital Universitario Central de Asturias, Oviedo, Spain.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Solowska JM, Garbern JY, Baas PW. Evaluation of loss of function as an explanation for SPG4-based hereditary spastic paraplegia. Hum Mol Genet 2010; 19:2767-79. [PMID: 20430936 DOI: 10.1093/hmg/ddq177] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The spectrum of mutations (missense, non-sense and splice-site) associated with hereditary spastic paraplegia 4 (HSP-SPG4) (SPG4:OMIM#182601) has suggested that this autosomal dominant disease results from loss of function. Because the protein encoded by SPG4, termed spastin, is a microtubule-severing enzyme, a loss-of-function scenario for the disease suggests that corticospinal axons degenerate due to inadequate microtubule severing resulting from inactivation of one spastin allele. Lending more complexity to the situation, there are two major isoforms of spastin (M1 and M87) translated from two start codons. M87 is widely expressed, while M1 is appreciably detected only in adult spinal cord. Here, we focused on four HSP-associated mutations of the SPG4 gene located outside of the AAA region essential for microtubule severing. We found that none of these mutations affected the enzymatic activity or expression levels of either M1 or M87. Three of the mutations resulted in dominant-negative activity of M1. Surprisingly, the S44L mutation, which is asymptomatic when present heterozygously, conferred dominant-negative activity, while the E112K mutation, which is symptomatic when present heterozygously, did not. Clinical symptoms reported for patients carrying the dominant-negative mutations L195V or 46Stop are not more severe than those reported for patients carrying the non-dominant-negative E112K mutation. These results indicate that there are cases of HSP-SPG4 that cannot be explained by insufficient spastin microtubule-severing activity.
Collapse
Affiliation(s)
- Joanna M Solowska
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA 19129, USA
| | | | | |
Collapse
|
41
|
Braschinsky M, Tamm R, Beetz C, Sachez-Ferrero E, Raukas E, Lüüs SM, Gross-Paju K, Boillot C, Canzian F, Metspalu A, Haldre S. Unique spectrum of SPAST variants in Estonian HSP patients: presence of benign missense changes but lack of exonic rearrangements. BMC Neurol 2010; 10:17. [PMID: 20214791 PMCID: PMC2841126 DOI: 10.1186/1471-2377-10-17] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Accepted: 03/09/2010] [Indexed: 11/29/2022] Open
Abstract
Background Hereditary spastic paraplegia (HSP) is a clinically and genetically heterogeneous disorder that can be an autosomal-dominant, autosomal-recessive, or X-linked disease. The most common autosomal-dominant form of the disease derives from mutations in the SPAST gene. Methods The aim of this study was to analyze 49 patients diagnosed with HSP from the Estonian population for sequence variants of the SPAST gene and to describe the associated phenotypes. Healthy control individuals (n = 100) with no family history of HSP were also analyzed. All patient samples were screened using denaturing high performance liquid chromatography (DHPLC) and multiplex ligation-dependent probe amplification (MLPA) assay. Samples with abnormal DHPLC and MLPA profiles were sequenced, with the same regions sequenced in control samples. Results Sequence variants of SPAST were identified in 19/49 HSP patients (38.8%), twelve among them had pathogenic mutations. Within the latter group there was one sporadic case. Eight patients had pure, and four - complex HSP. The twelve variants were identified: seven pathogenic (c.1174-1G>C, c.1185delA, c.1276C>T, c.1352_1356delGAGAA, c.1378C>A, c.1518_1519insTC, c.1841_1842insA) and five non-pathogenic (c.131C>T, c.484G>A, c.685A>G, c.1245+202delG, c.1245+215G>C). Only 2 of these mutations had previously been described (c.131C>T, c.1245+202delG). Three mutations, c.1174-1G>C, c.1276 C>T, c.1378C>A, showed intrafamilial segregation. Conclusion This study identified new variants of the SPAST gene which included benign missense variants and short insertions/deletions. No large rearrangements were found. Based on these data, 7 new pathogenic variants of HSP are associated with clinical phenotypes.
Collapse
|
42
|
Du F, Ozdowski EF, Kotowski IK, Marchuk DA, Sherwood NT. Functional conservation of human Spastin in a Drosophila model of autosomal dominant-hereditary spastic paraplegia. Hum Mol Genet 2010; 19:1883-96. [PMID: 20154342 DOI: 10.1093/hmg/ddq064] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Mutations in spastin are the most frequent cause of the neurodegenerative disease autosomal dominant-hereditary spastic paraplegia (AD-HSP). Drosophila melanogaster lacking spastin exhibit striking behavioral similarities to human patients suffering from AD-HSP, suggesting conservation of Spastin function between the species. Consistent with this, we show that exogenous expression of wild-type Drosophila or human spastin rescues behavioral and cellular defects in spastin null flies equivalently. This enabled us to generate genetically representative models of AD-HSP, which arises from dominant mutations in spastin rather than a complete loss of the gene. Flies co-expressing one copy of wild-type human spastin and one encoding the K388R catalytic domain mutation in the fly spastin null background, exhibit aberrant distal synapse morphology and microtubule distribution, similar to but less severe than spastin nulls. R388 or a separate nonsense mutation act dominantly and are furthermore sufficient to confer partial rescue, supporting in vitro evidence for additional, non-catalytic Spastin functions. Using this model, we tested the observation from human pedigrees that S44L and P45Q are trans-acting modifiers of mutations affecting the Spastin catalytic domain. As in humans, both L44 and Q45 are largely silent when heterozygous, but exacerbate mutant phenotypes when expressed in trans with R388. These transgenic 'AD-HSP' flies therefore provide a powerful and tractable model to enhance our understanding of the cellular and behavioral consequences of human spastin mutations and test hypotheses directly relevant to the human disease.
Collapse
Affiliation(s)
- Fang Du
- Department of Biology and Institute for Genome Sciences and Policy, Duke University, Durham, NC 27708, USA
| | | | | | | | | |
Collapse
|
43
|
Congenital bovine spinal dysmyelination is caused by a missense mutation in the SPAST gene. Neurogenetics 2009; 11:175-83. [PMID: 19714378 PMCID: PMC2854348 DOI: 10.1007/s10048-009-0214-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2009] [Accepted: 08/04/2009] [Indexed: 11/01/2022]
Abstract
Bovine spinal dysmyelination (BSD) is a recessive congenital neurodegenerative disease in cattle (Bos taurus) characterized by pathological changes of the myelin sheaths in the spinal cord. The occurrence of BSD is a longstanding problem in the American Brown Swiss (ABS) breed and in several European cattle breeds upgraded with ABS. Here, we show that the disease locus on bovine chromosome 11 harbors the SPAST gene that, when mutated, is responsible for the human disorder hereditary spastic paraplegia (HSP). Initially, SPAST encoding Spastin was considered a less likely candidate gene for BSD since the modes of inheritance as well as the time of onset and severity of symptoms differ widely between HSP and BSD. However, sequence analysis of the bovine SPAST gene in affected animals identified a R560Q substitution at a position in the ATPase domain of the Spastin protein that is invariant from insects to mammals. Interestingly, three different mutations in human SPAST gene at the equivalent position are known to cause HSP. To explore this observation further, we genotyped more than 3,100 animals of various cattle breeds and found that the glutamine allele exclusively occurred in breeds upgraded with ABS. Furthermore, all confirmed BSD carriers were heterozygous, while all affected calves were homozygous for the glutamine allele consistent with recessive transmission of the underlying mutation and complete penetrance in the homozygous state. Subsequent analysis of recombinant Spastin in vitro showed that the R560Q substitution severely impaired the ATPase activity, demonstrating a causal relationship between the SPAST mutation and BSD.
Collapse
|
44
|
Svenstrup K, Bross P, Koefoed P, Hjermind LE, Eiberg H, Born AP, Vissing J, Gyllenborg J, Nørremølle A, Hasholt L, Nielsen JE. Sequence variants in SPAST, SPG3A and HSPD1 in hereditary spastic paraplegia. J Neurol Sci 2009; 284:90-5. [PMID: 19423133 DOI: 10.1016/j.jns.2009.04.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2009] [Revised: 03/16/2009] [Accepted: 04/15/2009] [Indexed: 11/18/2022]
Abstract
Hereditary spastic paraplegia (HSP) is a group of clinically and genetically heterogeneous neurodegenerative disorders characterized by progressive spasticity and weakness in the lower limbs. The most common forms of autosomal dominant HSP, SPG4 and SPG3, are caused by sequence variants in the SPAST and SPG3A genes, respectively. The pathogenic variants are scattered all over these genes and many variants are unique to a specific family. The phenotype in SPG4 patients can be modified by a variant in SPAST (p.Ser44Leu) and recently, a variant in HSPD1, the gene underlying SPG13, was reported as a second genetic modifier in SPG4 patients. In this study HSP patients were screened for variants in SPG3A, SPAST and HSPD1 in order to identify disease causing variations. SPAST was sequenced in all patients whereas subsets were sequenced in HSPD1 and in selected exons of SPG3A. SPG4 patients and their HSP relatives were genotyped for the modifying variant in HSPD1. We report six new sequence variants in SPAST including a fourth non synonymous sequence variant in exon 1 and two synonymous changes of which one has been found in a HSP patient previously, but never in controls. Of the novel variants in SPAST four were interpreted as disease causing. In addition one new disease causing sequence variant and one non pathogenic non synonymous variant were found in SPG3A. In HSPD1 we identified a sporadic patient homozygote for the potential modifying variation. The effect of the modifying HSPD1 variation was not supported by identification in one SPG4 family.
Collapse
Affiliation(s)
- Kirsten Svenstrup
- Section of Neurogenetics, Department of Cellular and Molecular Medicine, University of Copenhagen, Denmark.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
45
|
Kasher PR, De Vos KJ, Wharton SB, Manser C, Bennett EJ, Bingley M, Wood JD, Milner R, McDermott CJ, Miller CCJ, Shaw PJ, Grierson AJ. Direct evidence for axonal transport defects in a novel mouse model of mutant spastin-induced hereditary spastic paraplegia (HSP) and human HSP patients. J Neurochem 2009; 110:34-44. [PMID: 19453301 DOI: 10.1111/j.1471-4159.2009.06104.x] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Mutations in spastin are the most common cause of hereditary spastic paraplegia (HSP) but the mechanisms by which mutant spastin induces disease are not clear. Spastin functions to regulate microtubule organisation, and because of the essential role of microtubules in axonal transport, this has led to the suggestion that defects in axonal transport may underlie at least part of the disease process in HSP. However, as yet there is no direct evidence to support this notion. Here we analysed axonal transport in a novel mouse model of spastin-induced HSP that involves a pathogenic splice site mutation, which leads to a loss of spastin protein. A mutation located within the same splice site has been previously described in HSP. Spastin mice develop gait abnormalities that correlate with phenotypes seen in HSP patients and also axonal swellings containing cytoskeletal proteins, mitochondria and the amyloid precursor protein (APP). Pathological analyses of human HSP cases caused by spastin mutations revealed the presence of similar axonal swellings. To determine whether mutant spastin influenced axonal transport we quantified transport of two cargoes, mitochondria and APP-containing membrane bound organelles, in neurons from mutant spastin and control mice, using time-lapse microscopy. We found that mutant spastin perturbs anterograde transport of both cargoes. In neurons with axonal swellings we found that the mitochondrial axonal transport defects were exacerbated; distal to axonal swellings both anterograde and retrograde transport were severely reduced. These results strongly support a direct role for defective axonal transport in the pathogenesis of HSP because of spastin mutation.
Collapse
Affiliation(s)
- Paul R Kasher
- Academic Neurology Unit, School of Medicine and Biomedical Sciences, University of Sheffield, Sheffield, UK
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
46
|
Riano E, Martignoni M, Mancuso G, Cartelli D, Crippa F, Toldo I, Siciliano G, Di Bella D, Taroni F, Bassi MT, Cappelletti G, Rugarli EI. Pleiotropic effects of spastin on neurite growth depending on expression levels. J Neurochem 2009; 108:1277-88. [PMID: 19141076 DOI: 10.1111/j.1471-4159.2009.05875.x] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Hereditary spastic paraplegia (HSP) is characterized by weakness and spasticity of the lower limbs, owing to degeneration of corticospinal axons. The most common form is due to heterozygous mutations in the SPG4 gene, encoding spastin, a microtubule (MT)-severing protein. Here, we show that neurite growth in immortalized and primary neurons responds in pleiotropic ways to changes in spastin levels. Spastin depletion alters the development of primary hippocampal neurons leading to abnormal neuron morphology, dystrophic neurites, and axonal growth defects. By live imaging with End-Binding Protein 3-Fluorescent Green Protein (EB3-GFP), a MT plus-end tracking protein, we ascertained that the assembly rate of MTs is reduced when spastin is down-regulated. Spastin over-expression at high levels strongly suppresses neurite maintenance, while slight spastin up-regulation using an endogenous promoter enhances neurite branching and elongation. Spastin severing activity is exerted preferentially on stable acetylated and detyrosinated MTs. We further show that SPG4 nonsense or splice site mutations found in hereditary spastic paraplegia patients result in reduced spastin levels, supporting haploinsufficiency as the molecular cause of the disease. Our study reveals that SPG4 is a dosage-sensitive gene, and broadens the understanding of the role of spastin in neurite growth and MT dynamics.
Collapse
Affiliation(s)
- Elena Riano
- Division of Biochemistry and Genetics, Istituto Neurologico "C. Besta", Milan, Italy
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
47
|
Münch C, Rolfs A, Meyer T. Heterozygous S44L missense change of the spastin gene in amyotrophic lateral sclerosis. ACTA ACUST UNITED AC 2008; 9:251-3. [PMID: 18608088 DOI: 10.1080/17482960801900172] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The authors present a 50-year-old patient with adult-onset amyotrophic lateral sclerosis (ALS) that was rapidly progressing. Screening of the spastin gene revealed a heterozygous missense change S44L. We excluded the involvement of the ALS-linked gene for copper/zinc superoxide dismutase (SOD1). This unusual phenotype shows that allelic variants of spastin may predispose bearers to a greater spectrum of motor neuron disorders including ALS.
Collapse
Affiliation(s)
- Christoph Münch
- Department of Neurology, Jewish Hospital Berlin, Berlin, Germany
| | | | | |
Collapse
|
48
|
Shoukier M, Neesen J, Sauter SM, Argyriou L, Doerwald N, Pantakani DVK, Mannan AU. Expansion of mutation spectrum, determination of mutation cluster regions and predictive structural classification of SPAST mutations in hereditary spastic paraplegia. Eur J Hum Genet 2008; 17:187-94. [PMID: 18701882 DOI: 10.1038/ejhg.2008.147] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The SPAST gene encoding for spastin plays a central role in the genetically heterogeneous group of diseases termed hereditary spastic paraplegia (HSP). In this study, we attempted to expand and refine the genetic and phenotypic characteristics of SPAST associated HSP by examining a large cohort of HSP patients/families. Screening of 200 unrelated HSP cases for mutations in the SPAST gene led to detection of 57 mutations (28.5%), of which 47 were distinct and 29 were novel mutations. The distribution analysis of known SPAST mutations over the structural domains of spastin led to the identification of several regions where the mutations were clustered. Mainly, the clustering was observed in the AAA (ATPases associated with diverse cellular activities) domain; however, significant clustering was also observed in the MIT (microtubule interacting and trafficking), MTBD (microtubule-binding domain) and an N-terminal region (228-269 residues). Furthermore, we used a previously generated structural model of spastin as a framework to classify the missense mutations in the AAA domain from the HSP patients into different structural/functional groups. Our data also suggest a tentative genotype-phenotype correlation and indicate that the missense mutations could cause an earlier onset of the disease.
Collapse
Affiliation(s)
- Moneef Shoukier
- Institute of Human Genetics, University of Goettingen, Goettingen, Germany
| | | | | | | | | | | | | |
Collapse
|
49
|
A cryptic promoter in the first exon of the SPG4 gene directs the synthesis of the 60-kDa spastin isoform. BMC Biol 2008; 6:31. [PMID: 18613979 PMCID: PMC2474578 DOI: 10.1186/1741-7007-6-31] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2008] [Accepted: 07/09/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Mutations in SPG4 cause the most common form of autosomal dominant hereditary spastic paraplegia, a neurodegenerative disease characterized by weakness and spasticity of the lower limbs due to degeneration of the corticospinal tract. SPG4 encodes spastin, a microtubule-severing ATPase belonging to the AAA family. Two isoforms of spastin, 68 and 60 kDa, respectively, are variably abundant in tissues, show different subcellular localizations and interact with distinct molecules. The isoforms arise through alternative initiation of translation from two AUG codons in exon 1; however, it is unclear how regulation of their expression may be achieved. RESULTS We present data that rule out the hypothesis that a cap-independent mechanism may be involved in the translation of the 60-kDa spastin isoform. Instead, we provide evidence for a complex transcriptional regulation of SPG4 that involves both a TATA-less ubiquitous promoter and a cryptic promoter in exon 1. The cryptic promoter covers the 5'-UTR and overlaps with the coding region of the gene. By using promoter-less constructs in various experimental settings, we found that the cryptic promoter is active in HeLa, HEK293 and motoneuronal NSC34 cells but not in SH-SY-5Y neuroblastoma cells. We showed that the cryptic promoter directs the synthesis of a SPG4 transcript that contains a shorter 5'-UTR and translates the 60-kDa spastin isoform selectively. Two polymorphisms (S44L and P45Q), leading to an early onset severe form of hereditary spastic paraplegia when present in heterozygosity with a mutant allele, fall a few nucleotides downstream of the novel transcriptional start site, opening up the possibility that they may exert their modifier effect at the transcriptional level. We provide evidence that at least one of them decreases the activity of the cryptic promoter in luciferase assays. CONCLUSION We identified a cryptic promoter in exon 1 of the SPG4 gene that selectively drives the expression of the 60-kDa spastin isoform in a tissue-regulated manner. These data may have implications for the understanding of the biology of spastin and the pathogenic basis of hereditary spastic paraplegia.
Collapse
|
50
|
|