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Bourcier D, Bélanger M, Côté I, Brais B, Synofzik M, Brisson JD, Rodrigue X, Gagnon MM, Mathieu J, Gagnon C. Documenting the psychometric properties of the scale for the assessment and rating of ataxia to advance trial readiness of Autosomal Recessive Spastic Ataxia of Charlevoix-Saguenay. J Neurol Sci 2020; 417:117050. [DOI: 10.1016/j.jns.2020.117050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 07/13/2020] [Accepted: 07/16/2020] [Indexed: 12/28/2022]
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Xiromerisiou G, Dadouli K, Marogianni C, Provatas A, Ntellas P, Rikos D, Stathis P, Georgouli D, Loules G, Zamanakou M, Hadjigeorgiou GM. A novel homozygous SACS mutation identified by whole exome sequencing-genotype phenotype correlations of all published cases. J Mol Neurosci 2019; 70:131-141. [PMID: 31701440 DOI: 10.1007/s12031-019-01410-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 09/26/2019] [Indexed: 02/07/2023]
Abstract
ARSACS is an autosomal recessive disorder characterized by ataxia, spasticity, and polyneuropathy. A plethora of worldwide distributed mutations have been described so far. Here, we report two brothers, born to non-consanguineous parents, presenting with cerebellar ataxia and peripheral neuropathy. Whole-exome sequencing revealed the presence of a novel homozygous variant in the SACS gene. The variant was confirmed by Sanger sequencing and found at heterozygous state in both parents. This is the first reported mutation in this gene, in Greek population. This case report further highlights the growing trend of identifying genetic diseases previously restricted to single, ethnically isolated regions in many different ethnic groups worldwide. Additionally, we performed a systematic review of all published cases with SACs mutations. ARSACS seems to be an important cause of ataxia and many different types of mutations have been identified, mainly located in exon 10. We evaluated the mutation pathogenicity in all previously reported cases to investigate possible phenotype-genotype correlations. We managed to find a correlation between the pathogenicity of mutations, severity of the phenotype, and age of onset of ARSACS. Greater mutation numbers in different populations will be important and mutation-specific functional studies will be essential to identify the pathogenicity of the various ARSACS variants.
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Affiliation(s)
- Georgia Xiromerisiou
- Department of Neurology, University Hospital of Larissa, Faculty of Medicine, School of Health Sciences, University of Thessaly, Larissa, Greece.
| | - Katerina Dadouli
- Department of Hygiene and Epidemiology, Faculty of Medicine, University of Thessaly, Larissa, Greece
| | - Chrysoula Marogianni
- Department of Neurology, University of Thessaly, University Hospital of Larissa, Larissa, Greece
| | - Antonios Provatas
- Department of Neurology, University of Thessaly, University Hospital of Larissa, Larissa, Greece
| | - Panagiotis Ntellas
- Department of Medical Oncology, University Hospital of Ioannina, Ioannina, Greece
| | - Dimitrios Rikos
- Department of Neurology, University of Thessaly, University Hospital of Larissa, Larissa, Greece
| | - Pantelis Stathis
- Department of Neurology, Mediterraneo Hospital, Glyfada, Athens, Greece
| | - Despina Georgouli
- Department of Neurology, University of Thessaly, University Hospital of Larissa, Larissa, Greece
| | | | | | - Georgios M Hadjigeorgiou
- Department of Neurology, Laboratory of Neurogenetics, University of Thessaly, University Hospital of Larissa, Larissa, Greece.,Department of Neurology, Medical School, University of Cyprus, Nicosia, Cyprus
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Larivière R, Sgarioto N, Márquez BT, Gaudet R, Choquet K, McKinney RA, Watt AJ, Brais B. Sacs R272C missense homozygous mice develop an ataxia phenotype. Mol Brain 2019; 12:19. [PMID: 30866998 PMCID: PMC6416858 DOI: 10.1186/s13041-019-0438-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 02/25/2019] [Indexed: 12/29/2022] Open
Abstract
Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS [MIM 270550]) is an early-onset neurodegenerative disorder caused by mutations in the SACS gene. Over 200 SACS mutations have been identified. Most mutations lead to a complete loss of a sacsin, a large 520 kD protein, although some missense mutations are associated with low levels of sacsin expression. We previously showed that Sacs knock-out mice demonstrate early-onset ataxic phenotype with neurofilament bundling in many neuronal populations. To determine if the preservation of some mutated sacsin protein resulted in the same cellular and behavioral alterations, we generated mice expressing an R272C missense mutation, a homozygote mutation found in some affected patients. Though SacsR272C mice express 21% of wild type brain sacsin and sacsin is found in many neurons, they display similar abnormalities to Sacs knock-out mice, including the development of an ataxic phenotype, reduced Purkinje cell firing rates, and somatodendritic neurofilament bundles in Purkinje cells and other neurons. Together our results support that Sacs missense mutation largely lead to loss of sacsin function.
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Affiliation(s)
- Roxanne Larivière
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Room 622, 3801, University Street, Montreal, Québec, H3A 2B4, Canada
| | - Nicolas Sgarioto
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Room 622, 3801, University Street, Montreal, Québec, H3A 2B4, Canada
| | | | - Rébecca Gaudet
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Room 622, 3801, University Street, Montreal, Québec, H3A 2B4, Canada
| | - Karine Choquet
- Department of Human Genetics, Montreal Neurological Institute, McGill University, Montreal, Qc, Canada
| | - R Anne McKinney
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Qc, Canada
| | - Alanna J Watt
- Department of Biology, McGill University, Montreal, Qc, Canada
| | - Bernard Brais
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Room 622, 3801, University Street, Montreal, Québec, H3A 2B4, Canada.
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Ménade M, Kozlov G, Trempe JF, Pande H, Shenker S, Wickremasinghe S, Li X, Hojjat H, Dicaire MJ, Brais B, McPherson PS, Wong MJH, Young JC, Gehring K. Structures of ubiquitin-like (Ubl) and Hsp90-like domains of sacsin provide insight into pathological mutations. J Biol Chem 2018; 293:12832-12842. [PMID: 29945973 PMCID: PMC6102131 DOI: 10.1074/jbc.ra118.003939] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Indexed: 01/07/2023] Open
Abstract
Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is a neurodegenerative disease that is caused by mutations in the SACS gene. The product of this gene is a very large 520-kDa cytoplasmic protein, sacsin, with a ubiquitin-like (Ubl) domain at the N terminus followed by three large sacsin internal repeat (SIRPT) supradomains and C-terminal J and HEPN domains. The SIRPTs are predicted to contain Hsp90-like domains, suggesting a potential chaperone activity. In this work, we report the structures of the Hsp90-like Sr1 domain of SIRPT1 and the N-terminal Ubl domain determined at 1.55- and 2.1-Å resolutions, respectively. The Ubl domain crystallized as a swapped dimer that could be relevant in the context of full-length protein. The Sr1 domain displays the Bergerat protein fold with a characteristic nucleotide-binding pocket, although it binds nucleotides with very low affinity. The Sr1 structure reveals that ARSACS-causing missense mutations (R272H, R272C, and T201K) disrupt protein folding, most likely leading to sacsin degradation. This work lends structural support to the view of sacsin as a molecular chaperone and provides a framework for future studies of this protein.
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Affiliation(s)
- Marie Ménade
- From the Department of Biochemistry, McGill Centre for Structural Biology, McGill University, Montreal, Quebec H3G 0B1, Canada and
| | - Guennadi Kozlov
- From the Department of Biochemistry, McGill Centre for Structural Biology, McGill University, Montreal, Quebec H3G 0B1, Canada and
| | - Jean-François Trempe
- From the Department of Biochemistry, McGill Centre for Structural Biology, McGill University, Montreal, Quebec H3G 0B1, Canada and
| | - Harshit Pande
- From the Department of Biochemistry, McGill Centre for Structural Biology, McGill University, Montreal, Quebec H3G 0B1, Canada and
| | - Solomon Shenker
- From the Department of Biochemistry, McGill Centre for Structural Biology, McGill University, Montreal, Quebec H3G 0B1, Canada and
| | - Sihara Wickremasinghe
- From the Department of Biochemistry, McGill Centre for Structural Biology, McGill University, Montreal, Quebec H3G 0B1, Canada and
| | - Xinlu Li
- From the Department of Biochemistry, McGill Centre for Structural Biology, McGill University, Montreal, Quebec H3G 0B1, Canada and
| | - Hamed Hojjat
- From the Department of Biochemistry, McGill Centre for Structural Biology, McGill University, Montreal, Quebec H3G 0B1, Canada and
| | - Marie-Josée Dicaire
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada
| | - Bernard Brais
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada
| | - Peter S. McPherson
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada
| | - Michael J. H. Wong
- From the Department of Biochemistry, McGill Centre for Structural Biology, McGill University, Montreal, Quebec H3G 0B1, Canada and
| | - Jason C. Young
- From the Department of Biochemistry, McGill Centre for Structural Biology, McGill University, Montreal, Quebec H3G 0B1, Canada and
| | - Kalle Gehring
- From the Department of Biochemistry, McGill Centre for Structural Biology, McGill University, Montreal, Quebec H3G 0B1, Canada and , To whom correspondence should be addressed:
Dept. of Biochemistry, McGill University, 3649 Promenade Sir William Osler, Rm. 473, Montreal, Quebec H3G 0B1, Canada. Tel.:
514-398-7287; E-mail:
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Pilliod J, Moutton S, Lavie J, Maurat E, Hubert C, Bellance N, Anheim M, Forlani S, Mochel F, N'Guyen K, Thauvin-Robinet C, Verny C, Milea D, Lesca G, Koenig M, Rodriguez D, Houcinat N, Van-Gils J, Durand CM, Guichet A, Barth M, Bonneau D, Convers P, Maillart E, Guyant-Marechal L, Hannequin D, Fromager G, Afenjar A, Chantot-Bastaraud S, Valence S, Charles P, Berquin P, Rooryck C, Bouron J, Brice A, Lacombe D, Rossignol R, Stevanin G, Benard G, Burglen L, Durr A, Goizet C, Coupry I. New practical definitions for the diagnosis of autosomal recessive spastic ataxia of Charlevoix-Saguenay. Ann Neurol 2015; 78:871-86. [PMID: 26288984 DOI: 10.1002/ana.24509] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2015] [Revised: 08/12/2015] [Accepted: 08/14/2015] [Indexed: 12/29/2022]
Abstract
OBJECTIVE Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is caused by mutations in the SACS gene. SACS encodes sacsin, a protein whose function remains unknown, despite the description of numerous protein domains and the recent focus on its potential role in the regulation of mitochondrial physiology. This study aimed to identify new mutations in a large population of ataxic patients and to functionally analyze their cellular effects in the mitochondrial compartment. METHODS A total of 321 index patients with spastic ataxia selected from the SPATAX network were analyzed by direct sequencing of the SACS gene, and 156 patients from the ATAXIC project presenting with congenital ataxia were investigated either by targeted or whole exome sequencing. For functional analyses, primary cultures of fibroblasts were obtained from 11 patients carrying either mono- or biallelic variants, including 1 case harboring a large deletion encompassing the entire SACS gene. RESULTS We identified biallelic SACS variants in 33 patients from SPATAX, and in 5 nonprogressive ataxia patients from ATAXIC. Moreover, a drastic and recurrent alteration of the mitochondrial network was observed in 10 of the 11 patients tested. INTERPRETATION Our results permit extension of the clinical and mutational spectrum of ARSACS patients. Moreover, we suggest that the observed mitochondrial network anomalies could be used as a trait biomarker for the diagnosis of ARSACS when SACS molecular results are difficult to interpret (ie, missense variants and heterozygous truncating variant). Based on our findings, we propose new diagnostic definitions for ARSACS using clinical, genetic, and cellular criteria.
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Affiliation(s)
- Julie Pilliod
- Rare Diseases Laboratory: Genetics and Metabolism, University of Bordeaux, Bordeaux, France
| | - Sébastien Moutton
- Rare Diseases Laboratory: Genetics and Metabolism, University of Bordeaux, Bordeaux, France.,Medical Genetics Service, Pellegrin University Hospital Center, Bordeaux, France
| | - Julie Lavie
- Rare Diseases Laboratory: Genetics and Metabolism, University of Bordeaux, Bordeaux, France
| | - Elise Maurat
- Rare Diseases Laboratory: Genetics and Metabolism, University of Bordeaux, Bordeaux, France
| | - Christophe Hubert
- Functional Genomics Center, University of Bordeaux, Bordeaux, France
| | - Nadège Bellance
- Rare Diseases Laboratory: Genetics and Metabolism, University of Bordeaux, Bordeaux, France
| | - Mathieu Anheim
- Neurology Service, Strasbourg University Hospitals, Strasbourg, France.,Molecular Cell Biology Genetics Institute, INSERM U964/CNRS UMR7104, University of Strasbourg, Illkirch-Graffenstaden, France.,Strasbourg Federation of Translational Medicine, University of Strasbourg, Illkirch-Graffenstaden, France
| | - Sylvie Forlani
- Genetics Service, Pitié-Salpêtrière Hospital, Public Hospital Network of Paris, Paris, France
| | - Fanny Mochel
- Genetics Service, Pitié-Salpêtrière Hospital, Public Hospital Network of Paris, Paris, France.,Brain and Spinal Cord Institute, INSERM U1127, CNRS UMR7225, Sorbonne Universities-Pierre and Marie Curie University, Paris, France
| | - Karine N'Guyen
- Department of Medical Genetics, Timone Hospital, Marseille, France
| | | | - Christophe Verny
- Nantes Angers le Mans University and Neurology Service, CNRS UMR6214, INSERM U1083, University Hospital Center, Angers, France
| | - Dan Milea
- Ophthalmology Service, Angers University Hospital Center, Angers, France and Singapore National Eye Centre, Singapore Eye Research Institute, Duke-National University of Singapore, Singapore
| | - Gaëtan Lesca
- Genetics Service, Lyon University Hospital Center, Lyon, France
| | - Michel Koenig
- Molecular Genetics Laboratory, INSERM U827, Montpellier Regional University Hospital Center, Montpellier, France
| | - Diana Rodriguez
- Rare Diseases Reference Center "Defects and Congenital Diseases of the Cerebellum," Armand Trousseau Hospital, Public Hospital Network of Paris, Paris, France.,Robert Debré Hospital, INSERM U1141, Paris, France.,Genetics Service, Armand Trousseau Hospital, Public Hospital Network of Paris, Paris, France
| | - Nada Houcinat
- Medical Genetics Service, Pellegrin University Hospital Center, Bordeaux, France
| | - Julien Van-Gils
- Medical Genetics Service, Pellegrin University Hospital Center, Bordeaux, France
| | - Christelle M Durand
- Rare Diseases Laboratory: Genetics and Metabolism, University of Bordeaux, Bordeaux, France
| | - Agnès Guichet
- Neuropediatrics Service, Armand Trousseau Hospital, Public Hospital Network of Paris, Sorbonne Universities-Pierre and Marie Curie University, Paris, France
| | - Magalie Barth
- Neuropediatrics Service, Armand Trousseau Hospital, Public Hospital Network of Paris, Sorbonne Universities-Pierre and Marie Curie University, Paris, France
| | - Dominique Bonneau
- Neuropediatrics Service, Armand Trousseau Hospital, Public Hospital Network of Paris, Sorbonne Universities-Pierre and Marie Curie University, Paris, France
| | - Philippe Convers
- Nantes Angers le Mans University and Department of Biochemistry and Genetics, University Hospital Center, Angers, France
| | - Elisabeth Maillart
- Clinical Neurophysiology Service, Saint-Étienne University Hospital Center, Saint-Étienne, France
| | - Lucie Guyant-Marechal
- Neurology Service, Pitié-Salpêtrière Hospital, Public Hospital Network of Paris, Paris, France
| | - Didier Hannequin
- Neurology Service, Pitié-Salpêtrière Hospital, Public Hospital Network of Paris, Paris, France
| | | | - Alexandra Afenjar
- Rare Diseases Reference Center "Defects and Congenital Diseases of the Cerebellum," Armand Trousseau Hospital, Public Hospital Network of Paris, Paris, France.,Neurologist, Caen, France
| | - Sandra Chantot-Bastaraud
- Rare Diseases Reference Center "Defects and Congenital Diseases of the Cerebellum," Armand Trousseau Hospital, Public Hospital Network of Paris, Paris, France.,Neurologist, Caen, France
| | - Stéphanie Valence
- Rare Diseases Reference Center "Defects and Congenital Diseases of the Cerebellum," Armand Trousseau Hospital, Public Hospital Network of Paris, Paris, France.,Genetics Service, Armand Trousseau Hospital, Public Hospital Network of Paris, Paris, France
| | - Perrine Charles
- Genetics Service, Pitié-Salpêtrière Hospital, Public Hospital Network of Paris, Paris, France
| | - Patrick Berquin
- Amiens University Hospital Center, Pediatric Neurology Activity Center, Amiens, France
| | - Caroline Rooryck
- Rare Diseases Laboratory: Genetics and Metabolism, University of Bordeaux, Bordeaux, France.,Medical Genetics Service, Pellegrin University Hospital Center, Bordeaux, France
| | - Julie Bouron
- Medical Genetics Service, Pellegrin University Hospital Center, Bordeaux, France
| | - Alexis Brice
- Genetics Service, Pitié-Salpêtrière Hospital, Public Hospital Network of Paris, Paris, France.,Brain and Spinal Cord Institute, INSERM U1127, CNRS UMR7225, Sorbonne Universities-Pierre and Marie Curie University, Paris, France
| | - Didier Lacombe
- Rare Diseases Laboratory: Genetics and Metabolism, University of Bordeaux, Bordeaux, France.,Medical Genetics Service, Pellegrin University Hospital Center, Bordeaux, France
| | - Rodrigue Rossignol
- Rare Diseases Laboratory: Genetics and Metabolism, University of Bordeaux, Bordeaux, France
| | - Giovanni Stevanin
- Genetics Service, Pitié-Salpêtrière Hospital, Public Hospital Network of Paris, Paris, France.,Brain and Spinal Cord Institute, INSERM U1127, CNRS UMR7225, Sorbonne Universities-Pierre and Marie Curie University, Paris, France.,Laboratory of Neurogenetics, Practical School of Higher Studies, Paris, France
| | - Giovanni Benard
- Rare Diseases Laboratory: Genetics and Metabolism, University of Bordeaux, Bordeaux, France
| | - Lydie Burglen
- Rare Diseases Reference Center "Defects and Congenital Diseases of the Cerebellum," Armand Trousseau Hospital, Public Hospital Network of Paris, Paris, France.,Robert Debré Hospital, INSERM U1141, Paris, France.,Neurologist, Caen, France
| | - Alexandra Durr
- Genetics Service, Pitié-Salpêtrière Hospital, Public Hospital Network of Paris, Paris, France.,Brain and Spinal Cord Institute, INSERM U1127, CNRS UMR7225, Sorbonne Universities-Pierre and Marie Curie University, Paris, France
| | - Cyril Goizet
- Rare Diseases Laboratory: Genetics and Metabolism, University of Bordeaux, Bordeaux, France.,Medical Genetics Service, Pellegrin University Hospital Center, Bordeaux, France
| | - Isabelle Coupry
- Rare Diseases Laboratory: Genetics and Metabolism, University of Bordeaux, Bordeaux, France
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Pyle A, Griffin H, Keogh MJ, Horvath R, Chinnery PF. Reply: Evaluation of exome sequencing variation in undiagnosed ataxias. Brain 2015; 138:e384. [PMID: 25842392 DOI: 10.1093/brain/awv088] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Angela Pyle
- Institute of Genetic Medicine, Newcastle University, NE1 3BZ, UK
| | - Helen Griffin
- Institute of Genetic Medicine, Newcastle University, NE1 3BZ, UK
| | - Michael J Keogh
- Institute of Genetic Medicine, Newcastle University, NE1 3BZ, UK
| | - Rita Horvath
- Institute of Genetic Medicine, Newcastle University, NE1 3BZ, UK
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Abstract
Abstract:Background:The growing number of spastic ataxia of Charlevoix-Saguenay (SACS) gene mutations reported worldwide has broadened the clinical phenotype of autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS). The identification of Quebec ARSACS cases without two knownSACSmutation led to the development of a multi-modal genomic strategy to uncover mutations in this large gene and explore phenotype variability.Methods:Search forSACSmutations by combining various methods on 20 cases with a classical French-Canadian ARSACS phenotype without two mutations and a group of 104 sporadic or recessive spastic ataxia cases of unknown cause. Western blot on lymphoblast protein from cases with different genotypes was probed to establish if they still expressed sacsin.Results:A total of 12 mutations, including 7 novels, were uncovered in Quebec ARSACS cases. The screening of 104 spastic ataxia cases of unknown cause for 98SACSmutations did not uncover carriers of two mutations. Compounds heterozygotes for one missenseSACSmutation were found to minimally express sacsin.Conclusions:The large number ofSACSmutations present even in Quebec suggests that the size of the gene alone may explain the great genotypic diversity. This study does not support an expanding ARSACS phenotype in the French-Canadian population. Most mutations lead to loss of function, though phenotypic variability in other populations may reflect partial loss of function with preservation of some sacsin expression. Our results also highlight the challenge ofSACSmutation screening and the necessity to develop new generation sequencing methods to ensure low cost complete gene sequencing.
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Romano A, Tessa A, Barca A, Fattori F, de Leva MF, Terracciano A, Storelli C, Santorelli FM, Verri T. Comparative analysis and functional mapping of SACS mutations reveal novel insights into sacsin repeated architecture. Hum Mutat 2013; 34:525-37. [PMID: 23280630 PMCID: PMC3629688 DOI: 10.1002/humu.22269] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Accepted: 12/06/2012] [Indexed: 01/01/2023]
Abstract
Autosomal recessive spastic ataxia of Charlevoix–Saguenay (ARSACS) is a neurological disease with mutations in SACS, encoding sacsin, a multidomain protein of 4,579 amino acids. The large size of SACS and its translated protein has hindered biochemical analysis of ARSACS, and how mutant sacsins lead to disease remains largely unknown. Three repeated sequences, called sacsin repeating region (SRR) supradomains, have been recognized, which contribute to sacsin chaperone-like activity. We found that the three SRRs are much larger (≥1,100 residues) than previously described, and organized in discrete subrepeats. We named the large repeated regions Sacsin Internal RePeaTs (SIRPT1, SIRPT2, and SIRPT3) and the subrepeats sr1, sr2, sr3, and srX. Comparative analysis of vertebrate sacsins in combination with fine positional mapping of a set of human mutations revealed that sr1, sr2, sr3, and srX are functional. Notably, the position of the pathogenic mutations in sr1, sr2, sr3, and srX appeared to be related to the severity of the clinical phenotype, as assessed by defining a severity scoring system. Our results suggest that the relative position of mutations in subrepeats will variably influence sacsin dysfunction. The characterization of the specific role of each repeated region will help in developing a comprehensive and integrated pathophysiological model of function for sacsin.
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Affiliation(s)
- Alessandro Romano
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Lecce, Italy
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10
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Samuels ME, Majewski J, Alirezaie N, Fernandez I, Casals F, Patey N, Decaluwe H, Gosselin I, Haddad E, Hodgkinson A, Idaghdour Y, Marchand V, Michaud JL, Rodrigue MA, Desjardins S, Dubois S, Le Deist F, Awadalla P, Raymond V, Maranda B. Exome sequencing identifies mutations in the gene TTC7A in French-Canadian cases with hereditary multiple intestinal atresia. J Med Genet 2013; 50:324-9. [PMID: 23423984 PMCID: PMC3625823 DOI: 10.1136/jmedgenet-2012-101483] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Accepted: 01/22/2013] [Indexed: 12/23/2022]
Abstract
BACKGROUND Congenital multiple intestinal atresia (MIA) is a severe, fatal neonatal disorder, involving the occurrence of obstructions in the small and large intestines ultimately leading to organ failure. Surgical interventions are palliative but do not provide long-term survival. Severe immunodeficiency may be associated with the phenotype. A genetic basis for MIA is likely. We had previously ascertained a cohort of patients of French-Canadian origin, most of whom were deceased as infants or in utero. The goal of the study was to identify the molecular basis for the disease in the patients of this cohort. METHODS We performed whole exome sequencing on samples from five patients of four families. Validation of mutations and familial segregation was performed using standard Sanger sequencing in these and three additional families with deceased cases. Exon skipping was assessed by reverse transcription-PCR and Sanger sequencing. RESULTS Five patients from four different families were each homozygous for a four base intronic deletion in the gene TTC7A, immediately adjacent to a consensus GT splice donor site. The deletion was demonstrated to have deleterious effects on splicing causing the skipping of the attendant upstream coding exon, thereby leading to a predicted severe protein truncation. Parents were heterozygous carriers of the deletion in these families and in two additional families segregating affected cases. In a seventh family, an affected case was compound heterozygous for the same 4bp deletion and a second missense mutation p.L823P, also predicted as pathogenic. No other sequenced genes possessed deleterious variants explanatory for all patients in the cohort. Neither mutation was seen in a large set of control chromosomes. CONCLUSIONS Based on our genetic results, TTC7A is the likely causal gene for MIA.
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Affiliation(s)
- Mark E Samuels
- Centre de Recherche du CHU Ste-Justine, University of Montreal, Montreal, Quebec, Canada
| | - Jacek Majewski
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada
| | - Najmeh Alirezaie
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada
| | - Isabel Fernandez
- Centre de Recherche du CHU Ste-Justine, University of Montreal, Montreal, Quebec, Canada
- Department of Microbiology and Immunology, University of Montreal, Montreal, Quebec, Canada
| | - Ferran Casals
- Centre de Recherche du CHU Ste-Justine, University of Montreal, Montreal, Quebec, Canada
| | - Natalie Patey
- Centre de Recherche du CHU Ste-Justine, University of Montreal, Montreal, Quebec, Canada
- Department of Pathology, University of Montreal, Montreal, Quebec, Canada
| | - Hélène Decaluwe
- Centre de Recherche du CHU Ste-Justine, University of Montreal, Montreal, Quebec, Canada
- Department of Pediatrics, University of Montreal, Montreal, Quebec, Canada
| | - Isabelle Gosselin
- Department of Neurosciences, Centre de recherche du CHU de Québec, Université Laval, Québec City, Quebec, Canada
| | - Elie Haddad
- Centre de Recherche du CHU Ste-Justine, University of Montreal, Montreal, Quebec, Canada
- Department of Microbiology and Immunology, University of Montreal, Montreal, Quebec, Canada
- Department of Pediatrics, University of Montreal, Montreal, Quebec, Canada
| | - Alan Hodgkinson
- Centre de Recherche du CHU Ste-Justine, University of Montreal, Montreal, Quebec, Canada
| | - Youssef Idaghdour
- Centre de Recherche du CHU Ste-Justine, University of Montreal, Montreal, Quebec, Canada
| | - Valerie Marchand
- Centre de Recherche du CHU Ste-Justine, University of Montreal, Montreal, Quebec, Canada
- Department of Pediatrics, University of Montreal, Montreal, Quebec, Canada
| | - Jacques L Michaud
- Centre de Recherche du CHU Ste-Justine, University of Montreal, Montreal, Quebec, Canada
- Department of Pediatrics, University of Montreal, Montreal, Quebec, Canada
| | - Marc-André Rodrigue
- Department of Neurosciences, Centre de recherche du CHU de Québec, Université Laval, Québec City, Quebec, Canada
- Département de Médecine Moléculaire, Université Laval, Québec City, Quebec, Canada
| | - Sylvie Desjardins
- Department of Neurosciences, Centre de recherche du CHU de Québec, Université Laval, Québec City, Quebec, Canada
| | - Stéphane Dubois
- Department of Neurosciences, Centre de recherche du CHU de Québec, Université Laval, Québec City, Quebec, Canada
| | - Francoise Le Deist
- Centre de Recherche du CHU Ste-Justine, University of Montreal, Montreal, Quebec, Canada
- Department of Microbiology and Immunology, University of Montreal, Montreal, Quebec, Canada
| | - Philip Awadalla
- Centre de Recherche du CHU Ste-Justine, University of Montreal, Montreal, Quebec, Canada
- Department of Pediatrics, University of Montreal, Montreal, Quebec, Canada
| | - Vincent Raymond
- Department of Neurosciences, Centre de recherche du CHU de Québec, Université Laval, Québec City, Quebec, Canada
- Département de Médecine Moléculaire, Université Laval, Québec City, Quebec, Canada
| | - Bruno Maranda
- Medical Genetics Service, University of Sherbrooke, Sherbrooke, Quebec, Canada
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Dibilio V, Cavalcanti F, Nicoletti A, Mostile G, Bruno E, Annesi G, Tarantino P, Gagliardi M, Gambardella A, Quattrone A, Zappia M. Sacsin-Related Spastic Ataxia Caused by a Novel Missense Mutation p.Arg272His in a Patient from Sicily, Southern Italy. THE CEREBELLUM 2013; 12:589-92. [DOI: 10.1007/s12311-013-0451-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Narayanan V, Rice SG, Olfers SS, Sivakumar K. Autosomal recessive spastic ataxia of Charlevoix-Saguenay: compound heterozygotes for nonsense mutations of the SACS gene. J Child Neurol 2011; 26:1585-9. [PMID: 21745802 DOI: 10.1177/0883073811412825] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Mutations of the SACS gene have been reported in patients with autosomal recessive spastic ataxia of Charlevoix-Saguenay from Canada (Quebec), Tunisia, Japan, Turkey, Belgium, Italy, Spain, the Netherlands, and Germany. Features that distinguish autosomal recessive spastic ataxia of Charlevoix-Saguenay from other recessive ataxias include sensory motor polyneuropathy and hypermyelinated retinal nerve fibers. We describe the clinical, electrophysiological, and radiological features in 2 white American siblings diagnosed with autosomal recessive spastic ataxia of Charlevoix-Saguenay. The 2 affected children are compound heterozygotes for nonsense mutations of the SACS gene (c. 3484 G>T, p. E 1162 X; and c. 11,707 C>T, p. R 3903 X). We have measured allele-specific SACS mRNA abundance in peripheral blood and show that these specific mutant mRNAs are not degraded. We suggest that in children with early onset cerebellar ataxia and spasticity, ophthalmological examination and nerve conduction testing may guide genetic testing.
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Affiliation(s)
- Vinodh Narayanan
- St Joseph's Hospital and Medical Center, Phoenix, Arizona 85013, USA.
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Bouhlal Y, Amouri R, El Euch-Fayeche G, Hentati F. Autosomal recessive spastic ataxia of Charlevoix-Saguenay: an overview. Parkinsonism Relat Disord 2011; 17:418-22. [PMID: 21450511 DOI: 10.1016/j.parkreldis.2011.03.005] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Revised: 02/14/2011] [Accepted: 03/07/2011] [Indexed: 12/29/2022]
Abstract
Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is a distinct form of hereditary early-onset spastic ataxia related to progressive degeneration of the cerebellum and spinal cord. Following the description of the first patients in 1978, the gene responsible has been mapped and identified. It was also shown that the disease occurred worldwide with more than 70 mutations and diverse phenotypes. Because of the random partition of these mutations in the SACS gene particularly on the largest exon nine, and due to the significant clinical variability between patients described in different countries, it has been difficult to establish a genotype-phenotype correlation for the disease. This paper reviews the broad clinical features and the various molecular aspects of ARSACS, reported over the last 30 years highlighting the difficulty of finding correlations.
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Affiliation(s)
- Yosr Bouhlal
- Bioinformatics Facility, University of South Dakota, Vermillion, SD 57069, USA
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Mutations in centrosomal protein CEP152 in primary microcephaly families linked to MCPH4. Am J Hum Genet 2010; 87:40-51. [PMID: 20598275 DOI: 10.1016/j.ajhg.2010.06.003] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2010] [Revised: 05/27/2010] [Accepted: 06/04/2010] [Indexed: 12/31/2022] Open
Abstract
Primary microcephaly is a rare condition in which brain size is substantially diminished without other syndromic abnormalities. Seven autosomal loci have been genetically mapped, and the underlying causal genes have been identified for MCPH1, MCPH3, MCPH5, MCPH6, and MCPH7 but not for MCPH2 or MCPH4. The known genes play roles in mitosis and cell division. We ascertained three families from an Eastern Canadian subpopulation, each with one microcephalic child. Homozygosity analysis in two families using genome-wide dense SNP genotyping supported linkage to the published MCPH4 locus on chromosome 15q21.1. Sequencing of coding exons of candidate genes in the interval identified a nonconservative amino acid change in a highly conserved residue of the centrosomal protein CEP152. The affected children in these two families were both homozygous for this missense variant. The third affected child was compound heterozygous for the missense mutation plus a second, premature-termination mutation truncating a third of the protein and preventing its localization to centrosomes in transfected cells. CEP152 is the putative mammalian ortholog of Drosphila asterless, mutations in which affect mitosis in the fly. Published data from zebrafish are also consistent with a role of CEP152 in centrosome function. By RT-PCR, CEP152 is expressed in the embryonic mouse brain, similar to other MCPH genes. Like some other MCPH genes, CEP152 shows signatures of positive selection in the human lineage. CEP152 is a strong candidate for the causal gene underlying MCPH4 and may be an important gene in the evolution of human brain size.
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