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Zonta A, Brussino A, Dentelli P, Brusco A. A novel case of congenital spinocerebellar ataxia 5: further support for a specific phenotype associated with the p.(Arg480Trp) variant in SPTBN2. BMJ Case Rep 2020; 13:13/12/e238108. [PMID: 33318253 PMCID: PMC7737026 DOI: 10.1136/bcr-2020-238108] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
A 4-year-old girl was referred to the geneticist with a history of ataxia associated with intention tremor of the hands, strabismus and hypermetropy. Her symptoms presented about 2 years earlier with inability to walk unaided and lower limbs hypotonia. Cognitive functions were normal. Brain MRI showed a cerebellar and vermian hypoplasia with enlargement of both the cerebrospinal fluid spaces and the IV brain ventricle. Family history was unremarkable. A genetic screening using a 42-gene panel for hereditary ataxia/spastic paraparesis identified a de novo c.1438C>T - p.(Arg480Trp) missense change in the SPTBN2 gene (NM_006946.2). This variant is reported to be associated with congenital ataxia, later evolving into ataxia and intellectual disability. This case further supports the existence of a specific SPTBN2 p.(Arg480Trp)-associated phenotype, with a de novo recurrence of this variant in the heterozygous state.
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Affiliation(s)
- Andrea Zonta
- Medical Genetics Unit, Città della Salute e della Scienza University Hospital, Torino, Italy
| | | | | | - Alfredo Brusco
- Medical Genetics Unit, Città della Salute e della Scienza University Hospital, Torino, Italy,Department Medical Sciences, University of Turin, Torino, Italy
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2
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Giorgio E, Garelli E, Carando A, Bellora S, Rubino E, Quarello P, Sirchia F, Marrama F, Gallone S, Grosso E, Pasini B, Massa R, Brussino A, Brusco A. Design of a multiplex ligation-dependent probe amplification assay for SLC20A2: identification of two novel deletions in primary familial brain calcification. J Hum Genet 2019; 64:1083-1090. [PMID: 31501477 DOI: 10.1038/s10038-019-0668-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 08/16/2019] [Accepted: 08/19/2019] [Indexed: 01/13/2023]
Abstract
Primary familial brain calcification (PFBC) is a rare disease characterized by brain calcifications that mainly affect the basal ganglia, thalamus, and cerebellum. Among the four autosomal-dominant genes known to be associated with the disease, SLC20A2 pathogenic variants are the most common, accounting for up to 40% of PFBC dominant cases; variants include both point mutations, small insertions/deletions and intragenic deletions. Over the last 7 years, we have collected a group of 50 clinically diagnosed PFBC patients, who were screened for single nucleotide changes and small insertions/deletions in SLC20A2 by Sanger sequencing. We found seven pathogenic/likely pathogenic variants: four were previously described by our group, and three are reported here (c.303delG, c.21delG, and c.1795-1G>A). We developed and validated a synthetic Multiplex Ligation-dependent Probe Amplification (MLPA) assay for SLC20A2 deletions, covering all ten coding exons and the 5' UTR (SLC20A2-MLPA). Using this method, we screened a group of 43 PFBC-patients negative for point mutations and small insertions/deletions, and identified two novel intragenic deletions encompassing exon 6 NC_000008.10:g.(42297172_42302163)_(423022281_42317413)del, and exons 7-11 including the 3'UTR NC_000008.10:g.(?_42275320)_(42297172_42302163)del. Overall, SLC20A2 deletions may be highly underestimated PFBC cases, and we suggest MLPA should be included in the routine molecular test for PFBC diagnosis.
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Affiliation(s)
- Elisa Giorgio
- Department of Medical Sciences, University of Torino, Turin, Italy
| | - Emanuela Garelli
- Department of Public Health and Pediatric Sciences, University of Torino, Turin, Italy
| | - Adriana Carando
- Department of Public Health and Pediatric Sciences, University of Torino, Turin, Italy
| | - Stefania Bellora
- Pediatric Neuropsychiatry Unit, "SS Antonio e Biagio e Cesare Arrigo" Hospital, Alessandria, Italy
| | - Elisa Rubino
- Department of Neuroscience and Mental Health, AOU Città della Salute e della Scienza di Torino, Turin, Italy
| | - Paola Quarello
- Department of Public Health and Pediatric Sciences, University of Torino, Turin, Italy
| | - Fabio Sirchia
- Institute for Maternal and Child Health IRCCS Burlo Garofalo, Trieste, Italy
| | - Federico Marrama
- Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy
| | - Salvatore Gallone
- Department of Neuroscience "Rita Levi Montalcini", University of Torino, Turin, Italy
| | - Enrico Grosso
- Medical Genetics Unit, Città della Salute e della Scienza University Hospital, Turin, Italy
| | - Barbara Pasini
- Department of Medical Sciences, University of Torino, Turin, Italy.,Medical Genetics Unit, Città della Salute e della Scienza University Hospital, Turin, Italy
| | - Roberto Massa
- Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy
| | | | - Alfredo Brusco
- Department of Medical Sciences, University of Torino, Turin, Italy. .,Medical Genetics Unit, Città della Salute e della Scienza University Hospital, Turin, Italy.
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3
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Giorgio E, Lorenzati M, Rivetti di Val Cervo P, Brussino A, Cernigoj M, Della Sala E, Bartoletti Stella A, Ferrero M, Caiazzo M, Capellari S, Cortelli P, Conti L, Cattaneo E, Buffo A, Brusco A. Allele-specific silencing as treatment for gene duplication disorders: proof-of-principle in autosomal dominant leukodystrophy. Brain 2019; 142:1905-1920. [PMID: 31143934 DOI: 10.1093/brain/awz139] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 01/16/2019] [Accepted: 03/31/2019] [Indexed: 11/14/2022] Open
Abstract
Allele-specific silencing by RNA interference (ASP-siRNA) holds promise as a therapeutic strategy for downregulating a single mutant allele with minimal suppression of the corresponding wild-type allele. This approach has been effectively used to target autosomal dominant mutations and single nucleotide polymorphisms linked with aberrantly expanded trinucleotide repeats. Here, we propose ASP-siRNA as a preferable choice to target duplicated disease genes, avoiding potentially harmful excessive downregulation. As a proof-of-concept, we studied autosomal dominant adult-onset demyelinating leukodystrophy (ADLD) due to lamin B1 (LMNB1) duplication, a hereditary, progressive and fatal disorder affecting myelin in the CNS. Using a reporter system, we screened the most efficient ASP-siRNAs preferentially targeting one of the alleles at rs1051644 (average minor allele frequency: 0.45) located in the 3' untranslated region of the gene. We identified four siRNAs with a high efficacy and allele-specificity, which were tested in ADLD patient-derived fibroblasts. Three of the small interfering RNAs were highly selective for the target allele and restored both LMNB1 mRNA and protein levels close to control levels. Furthermore, small interfering RNA treatment abrogates the ADLD-specific phenotypes in fibroblasts and in two disease-relevant cellular models: murine oligodendrocytes overexpressing human LMNB1, and neurons directly reprogrammed from patients' fibroblasts. In conclusion, we demonstrated that ASP-silencing by RNA interference is a suitable and promising therapeutic option for ADLD. Moreover, our results have a broad translational value extending to several pathological conditions linked to gene-gain in copy number variations.
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Affiliation(s)
- Elisa Giorgio
- University of Torino, Department of Medical Sciences, Torino, Italy
| | - Martina Lorenzati
- University of Torino, Department of Neuroscience Rita Levi Montalcini and Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Torino, Italy
| | - Pia Rivetti di Val Cervo
- University of Milan, Department of Biosciences, Laboratory of Stem Cell Biology and Pharmacology of Neurodegenerative Diseases, Milan, Italy
| | | | - Manuel Cernigoj
- University of Milan, Department of Biosciences, Laboratory of Stem Cell Biology and Pharmacology of Neurodegenerative Diseases, Milan, Italy
| | | | | | - Marta Ferrero
- University of Torino, Department of Medical Sciences, Torino, Italy
| | - Massimiliano Caiazzo
- Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Universiteitsweg 99, CG, Utrecht, The Netherlands
- Department of Molecular Medicine and Medical Biotechnology, University of Naples 'Federico II', Naples, Italy
| | - Sabina Capellari
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Bellaria Hospital, Bologna, Italy
- University of Bologna, Department of Biomedical and Neuromotor Sciences, Bologna, Italy
| | - Pietro Cortelli
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Bellaria Hospital, Bologna, Italy
- University of Bologna, Department of Biomedical and Neuromotor Sciences, Bologna, Italy
| | - Luciano Conti
- University of Trento, Centre for Integrative Biology (CIBIO), Laboratory of Computational Oncology, Trento, Italy
| | - Elena Cattaneo
- University of Milan, Department of Biosciences, Laboratory of Stem Cell Biology and Pharmacology of Neurodegenerative Diseases, Milan, Italy
- National Institute of Molecular Genetics (INGM) Romeo and Enrica Invernizzi, Milano, Italy
| | - Annalisa Buffo
- University of Torino, Department of Neuroscience Rita Levi Montalcini and Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Torino, Italy
| | - Alfredo Brusco
- University of Torino, Department of Medical Sciences, Torino, Italy
- Città della Salute e della Scienza University Hospital, Medical Genetics Unit, Torino, Italy
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4
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Giorgio E, Sirchia F, Bosco M, Sobreira NLM, Grosso E, Brussino A, Brusco A. A novel case of Greenberg dysplasia and genotype-phenotype correlation analysis for LBR pathogenic variants: An instructive example of one gene-multiple phenotypes. Am J Med Genet A 2019; 179:306-311. [PMID: 30561119 PMCID: PMC6349533 DOI: 10.1002/ajmg.a.61000] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 11/06/2018] [Accepted: 11/06/2018] [Indexed: 12/30/2022]
Abstract
Greenberg skeletal dysplasia is an autosomal recessive, perinatal lethal disorder associated with biallelic variants affecting the lamin B receptor (LBR) gene. LBR is also associated with the autosomal recessive anadysplasia-like spondylometaphyseal dysplasia, and the autosomal dominant Pelger-Huët anomaly, a benign laminopathy characterized by anomalies in the nuclear shape of blood granulocytes. The LBR is an inner nuclear membrane protein that binds lamin B proteins (LMNB1 and LMNB2), interacts with chromatin, and exerts a sterol reductase activity. Here, we report on a novel LBR missense variant [c.1379A>G; p.(D460R)], identified by whole exome sequencing and causing Greenberg dysplasia in two fetuses from a consanguineous Moroccan family. We revised published LBR variants to propose a genotype-phenotype correlation in LBR associated diseases. The diverse phenotypes are correlated to the functional domain affected, the heterozygous or homozygous state of the variants, and their different impact on the residual protein function. LBR represents an instructive example of one gene presenting with two different patterns of inheritance and at least three different clinical phenotypes.
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Affiliation(s)
- Elisa Giorgio
- University of Torino, Department of Medical Sciences, Torino, Italy
| | - Fabio Sirchia
- University of Trieste, IRCCS Burlo Garofalo, Department of Advanced Diagnostic and Clinical Trials Institute for Maternal Child Health, Trieste, Italy
| | - Martino Bosco
- San Lazzaro Hospital, Pathological Anatomy and Histology unit, Alba, Italy
| | - Nara Lygia M. Sobreira
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Johns Hopkins University School of Medicine, Department of Pediatrics, Baltimore, MD, USA
| | | | - Enrico Grosso
- Città della Salute e della Scienza University Hospital, Medical Genetics Unit, Torino, Italy
| | | | - Alfredo Brusco
- University of Torino, Department of Medical Sciences, Torino, Italy
- Città della Salute e della Scienza University Hospital, Medical Genetics Unit, Torino, Italy
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5
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Mancini C, Zonta A, Botta G, Breda Klobus A, Valbonesi S, Pasini B, Giorgio E, Viora E, Brusco A, Brussino A. A fetal case of microphthalmia and limb anomalies with abnormal neuronal migration associated with SMOC1 biallelic variants. Eur J Med Genet 2018; 62:103578. [PMID: 30445150 DOI: 10.1016/j.ejmg.2018.11.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 09/26/2018] [Accepted: 11/09/2018] [Indexed: 01/30/2023]
Abstract
Microphthalmia with limb anomalies (MLA, OMIM, 206920) is a rare autosomal-recessive disease caused by biallelic pathogenic variants in the SMOC1 gene. It is characterized by ocular disorders (microphtalmia or anophtalmia) and limb anomalies (oligodactyly, syndactyly, and synostosis of the 4th and 5th metacarpals), variably associated with long bone hypoplasia, horseshoe kidney, venous anomalies, vertebral anomalies, developmental delay, and intellectual disability. Here, we report the case of a woman who interrupted her pregnancy after ultrasound scans revealed a depression of the frontal bone, posterior fossa anomalies, cerebral ventricular enlargement, cleft spine involving the sacral and lower-lumbar vertebrae, and bilateral microphthalmia. Micrognathia, four fingers in both feet and a slight tibial bowing were added to the clinical picture after fetal autopsy. Exome sequencing identified two variants in the SMOC1 gene, each inherited from one of the parents: c.709G>T - p.(Glu237*) on exon 8 and c.1223G>A - p.(Cys408Tyr) on exon 11, both predicted to be pathogenic by different bioinformatics software. Brain histopathology showed an abnormal cortical neuronal migration, which could be related to the SMOC1 protein function, given its role in cellular signaling, proliferation and migration. Finally, we summarize phenotypic and genetic data of known MLA cases showing that our case has some unique features (Chiari II malformation; focal neuropathological alterations) that could be part of the variable phenotype of SMOC1-associated diseases.
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Affiliation(s)
- Cecilia Mancini
- University of Torino, Department of Medical Sciences, 10126, Torino, Italy
| | - Andrea Zonta
- Città Della Salute e Della Scienza University Hospital, Medical Genetics Unit, 10126, Torino, Italy
| | - Giovanni Botta
- Città Della Salute e Della Scienza University Hospital, Departments of Pathology, 10126, Torino, Italy
| | | | | | - Barbara Pasini
- Città Della Salute e Della Scienza University Hospital, Medical Genetics Unit, 10126, Torino, Italy
| | - Elisa Giorgio
- University of Torino, Department of Medical Sciences, 10126, Torino, Italy
| | - Elsa Viora
- Città Della Salute e Della Scienza University Hospital, Department of Gynecology and Obstetrics, Ultrasound and Prenatal Diagnosis Unit, 10126, Torino, Italy
| | - Alfredo Brusco
- University of Torino, Department of Medical Sciences, 10126, Torino, Italy; Città Della Salute e Della Scienza University Hospital, Medical Genetics Unit, 10126, Torino, Italy.
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6
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Mancini C, Hoxha E, Iommarini L, Brussino A, Richter U, Montarolo F, Cagnoli C, Parolisi R, Gondor Morosini DI, Nicolò V, Maltecca F, Muratori L, Ronchi G, Geuna S, Arnaboldi F, Donetti E, Giorgio E, Cavalieri S, Di Gregorio E, Pozzi E, Ferrero M, Riberi E, Casari G, Altruda F, Turco E, Gasparre G, Battersby BJ, Porcelli AM, Ferrero E, Brusco A, Tempia F. Mice harbouring a SCA28 patient mutation in AFG3L2 develop late-onset ataxia associated with enhanced mitochondrial proteotoxicity. Neurobiol Dis 2018; 124:14-28. [PMID: 30389403 DOI: 10.1016/j.nbd.2018.10.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 10/05/2018] [Accepted: 10/28/2018] [Indexed: 12/20/2022] Open
Abstract
Spinocerebellar ataxia 28 is an autosomal dominant neurodegenerative disorder caused by missense mutations affecting the proteolytic domain of AFG3L2, a major component of the mitochondrial m-AAA protease. However, little is known of the underlying pathogenetic mechanisms or how to treat patients with SCA28. Currently available Afg3l2 mutant mice harbour deletions that lead to severe, early-onset neurological phenotypes that do not faithfully reproduce the late-onset and slowly progressing SCA28 phenotype. Here we describe production and detailed analysis of a new knock-in murine model harbouring an Afg3l2 allele carrying the p.Met665Arg patient-derived mutation. Heterozygous mutant mice developed normally but adult mice showed signs of cerebellar ataxia detectable by beam test. Although cerebellar pathology was negative, electrophysiological analysis showed a trend towards increased spontaneous firing in Purkinje cells from heterozygous mutants with respect to wild-type controls. As homozygous mutants died perinatally with evidence of cardiac atrophy, for each genotype we generated mouse embryonic fibroblasts (MEFs) to investigate mitochondrial function. MEFs from mutant mice showed altered mitochondrial bioenergetics, with decreased basal oxygen consumption rate, ATP synthesis and mitochondrial membrane potential. Mitochondrial network formation and morphology was altered, with greatly reduced expression of fusogenic Opa1 isoforms. Mitochondrial alterations were also detected in cerebella of 18-month-old heterozygous mutants and may be a hallmark of disease. Pharmacological inhibition of de novo mitochondrial protein translation with chloramphenicol caused reversal of mitochondrial morphology in homozygous mutant MEFs, supporting the relevance of mitochondrial proteotoxicity for SCA28 pathogenesis and therapy development.
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Affiliation(s)
- Cecilia Mancini
- Department of Medical Sciences, University of Torino, Torino, Italy
| | - Eriola Hoxha
- Department of Neuroscience, University of Torino, Torino, Italy; Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Italy
| | - Luisa Iommarini
- Department of Pharmacy and Biotechnologies (FABIT), University of Bologna, Bologna, Italy
| | | | - Uwe Richter
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Francesca Montarolo
- Department of Neuroscience, University of Torino, Torino, Italy; Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Italy
| | - Claudia Cagnoli
- Department of Medical Sciences, University of Torino, Torino, Italy
| | - Roberta Parolisi
- Department of Neuroscience, University of Torino, Torino, Italy; Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Italy
| | - Diana Iulia Gondor Morosini
- Department of Neuroscience, University of Torino, Torino, Italy; Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Italy
| | - Valentina Nicolò
- Department of Neuroscience, University of Torino, Torino, Italy; Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Italy
| | - Francesca Maltecca
- Università Vita-Salute San Raffaele, Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milan, Italy
| | - Luisa Muratori
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Italy; Department of Clinical and Biological Sciences, University of Torino, Torino, Italy
| | - Giulia Ronchi
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Italy; Department of Clinical and Biological Sciences, University of Torino, Torino, Italy
| | - Stefano Geuna
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Italy; Department of Clinical and Biological Sciences, University of Torino, Torino, Italy
| | - Francesca Arnaboldi
- Department of Biomedical Sciences for Health, Università degli Studi di Milano, Milan, Italy
| | - Elena Donetti
- Department of Biomedical Sciences for Health, Università degli Studi di Milano, Milan, Italy
| | - Elisa Giorgio
- Department of Medical Sciences, University of Torino, Torino, Italy
| | - Simona Cavalieri
- Department of Medical Sciences, University of Torino, Torino, Italy
| | - Eleonora Di Gregorio
- Medical Genetics Unit, Città della Salute e della Scienza University Hospital, Torino, Italy
| | - Elisa Pozzi
- Department of Medical Sciences, University of Torino, Torino, Italy
| | - Marta Ferrero
- Department of Medical Sciences, University of Torino, Torino, Italy
| | - Evelise Riberi
- Department of Public Health and Pediatrics, University of Torino, Torino, Italy
| | - Giorgio Casari
- Università Vita-Salute San Raffaele, Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milan, Italy
| | - Fiorella Altruda
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Emilia Turco
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Giuseppe Gasparre
- Department Medical and Surgical Sciences, Medical Genetics, University of Bologna, Bologna, Italy
| | | | - Anna Maria Porcelli
- Department of Pharmacy and Biotechnologies (FABIT), University of Bologna, Bologna, Italy
| | - Enza Ferrero
- Department of Medical Sciences, University of Torino, Torino, Italy
| | - Alfredo Brusco
- Department of Medical Sciences, University of Torino, Torino, Italy; Medical Genetics Unit, Città della Salute e della Scienza University Hospital, Torino, Italy.
| | - Filippo Tempia
- Department of Neuroscience, University of Torino, Torino, Italy; Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Italy
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7
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Cagnoli C, Brussino A, Mancini C, Ferrone M, Orsi L, Salmin P, Pappi P, Giorgio E, Pozzi E, Cavalieri S, Di Gregorio E, Ferrero M, Filla A, De Michele G, Gellera C, Mariotti C, Nethisinghe S, Giunti P, Stevanin G, Brusco A. Spinocerebellar Ataxia Tethering PCR: A Rapid Genetic Test for the Diagnosis of Spinocerebellar Ataxia Types 1, 2, 3, 6, and 7 by PCR and Capillary Electrophoresis. J Mol Diagn 2018; 20:289-297. [PMID: 29462666 DOI: 10.1016/j.jmoldx.2017.12.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 11/17/2017] [Accepted: 12/19/2017] [Indexed: 12/14/2022] Open
Abstract
Spinocerebellar ataxia (SCA) types 1, 2, 3, 6, and 7, associated with a (CAG)n repeat expansion in coding sequences, are the most prevalent autosomal dominant ataxias worldwide (approximately 60% of the cases). In addition, the phenotype of SCA2 expansions has been now extended to Parkinson disease and amyotrophic lateral sclerosis. Their diagnosis is currently based on a PCR to identify small expanded alleles, followed by a second-level test whenever a false normal homozygous or a CAT interruption in SCA1 needs to be verified. Next-generation sequencing still does not allow efficient detection of these repeats. Here, we show the efficacy of a novel, rapid, and cost-effective method to identify and size pathogenic expansions in SCA1, 2, 3, 6, and 7 and recognize large alleles or interruptions without a second-level test. Twenty-five healthy controls and 33 expansion carriers were analyzed: alleles migrated consistently in different PCRs and capillary runs, and homozygous individuals were always distinguishable from heterozygous carriers of both common and large (>100 repeats) pathogenic CAG expansions. Repeat number could be calculated counting the number of peaks, except for the largest SCA2 and SCA7 alleles. Interruptions in SCA1 were always visible. Overall, our method allows a simpler, cost-effective, and sensibly faster SCA diagnostic protocol compared with the standard technique and to the still unadapted next-generation sequencing.
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Affiliation(s)
- Claudia Cagnoli
- Department of Medical Sciences, University of Turin, Turin, Italy
| | | | - Cecilia Mancini
- Department of Medical Sciences, University of Turin, Turin, Italy
| | - Marina Ferrone
- Department of Medical Sciences, University of Turin, Turin, Italy; Medical Genetics Unit, Città della Salute e della Scienza University Hospital, Turin, Italy
| | - Laura Orsi
- Department of Laboratory Medicine, and the Neurologic Division I, Department of Neuroscience and Mental Health, Città della Salute e della Scienza University Hospital, Turin, Italy
| | - Paola Salmin
- Medical Genetics Unit, Città della Salute e della Scienza University Hospital, Turin, Italy
| | - Patrizia Pappi
- Medical Genetics Unit, Città della Salute e della Scienza University Hospital, Turin, Italy
| | - Elisa Giorgio
- Department of Medical Sciences, University of Turin, Turin, Italy
| | - Elisa Pozzi
- Department of Medical Sciences, University of Turin, Turin, Italy
| | - Simona Cavalieri
- Department of Medical Sciences, University of Turin, Turin, Italy
| | | | - Marta Ferrero
- Department of Medical Sciences, University of Turin, Turin, Italy
| | - Alessandro Filla
- Department of Neurosciences, Odontostomatological and Reproductive Sciences, University Federico II, Naples, Italy
| | - Giuseppe De Michele
- Department of Neurosciences, Odontostomatological and Reproductive Sciences, University Federico II, Naples, Italy
| | - Cinzia Gellera
- Unit of Genetics of Neurodegenerative and Metabolic Diseases, Fondazione IRCCS Carlo Besta Neurological Institute, Milan, Italy
| | - Caterina Mariotti
- Unit of Genetics of Neurodegenerative and Metabolic Diseases, Fondazione IRCCS Carlo Besta Neurological Institute, Milan, Italy
| | - Suran Nethisinghe
- Ataxia Centre, Department of Molecular Neuroscience, Institute of Neurology, University College London, London, United Kingdom
| | - Paola Giunti
- Ataxia Centre, Department of Molecular Neuroscience, Institute of Neurology, University College London, London, United Kingdom
| | - Giovanni Stevanin
- INSERM, U 1127, Institut du Cerveau et de la Moelle epinière, Paris, France; Centre National de la Recherche Scientifique UMR 7225, Paris, France; UMRS 1127, Université Pierre et Marie Curie (Paris 06), Sorbonne Universités, Paris, France; Ecole Pratique des Hautes Etudes, PSL Research University, Paris, France; Centre de Référence de Neurogénétique, Hôpital de la Pitié-Salpêtrière, Assistance Publique - Hôpitaux de Paris, Paris, France
| | - Alfredo Brusco
- Department of Medical Sciences, University of Turin, Turin, Italy; Medical Genetics Unit, Città della Salute e della Scienza University Hospital, Turin, Italy.
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8
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Di Gregorio E, Riberi E, Belligni EF, Biamino E, Spielmann M, Ala U, Calcia A, Bagnasco I, Carli D, Gai G, Giordano M, Guala A, Keller R, Mandrile G, Arduino C, Maffè A, Naretto VG, Sirchia F, Sorasio L, Ungari S, Zonta A, Zacchetti G, Talarico F, Pappi P, Cavalieri S, Giorgio E, Mancini C, Ferrero M, Brussino A, Savin E, Gandione M, Pelle A, Giachino DF, De Marchi M, Restagno G, Provero P, Cirillo Silengo M, Grosso E, Buxbaum JD, Pasini B, De Rubeis S, Brusco A, Ferrero GB. Copy number variants analysis in a cohort of isolated and syndromic developmental delay/intellectual disability reveals novel genomic disorders, position effects and candidate disease genes. Clin Genet 2017; 92:415-422. [PMID: 28295210 DOI: 10.1111/cge.13009] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 02/28/2017] [Accepted: 03/02/2017] [Indexed: 12/14/2022]
Abstract
BACKGROUND Array-comparative genomic hybridization (array-CGH) is a widely used technique to detect copy number variants (CNVs) associated with developmental delay/intellectual disability (DD/ID). AIMS Identification of genomic disorders in DD/ID. MATERIALS AND METHODS We performed a comprehensive array-CGH investigation of 1,015 consecutive cases with DD/ID and combined literature mining, genetic evidence, evolutionary constraint scores, and functional information in order to assess the pathogenicity of the CNVs. RESULTS We identified non-benign CNVs in 29% of patients. Amongst the pathogenic variants (11%), detected with a yield consistent with the literature, we found rare genomic disorders and CNVs spanning known disease genes. We further identified and discussed 51 cases with likely pathogenic CNVs spanning novel candidate genes, including genes encoding synaptic components and/or proteins involved in corticogenesis. Additionally, we identified two deletions spanning potential Topological Associated Domain (TAD) boundaries probably affecting the regulatory landscape. DISCUSSION AND CONCLUSION We show how phenotypic and genetic analyses of array-CGH data allow unraveling complex cases, identifying rare disease genes, and revealing unexpected position effects.
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Affiliation(s)
- E Di Gregorio
- University of Torino, Department of Medical Sciences, Turin, Italy.,Medical Genetics Unit, Città della Salute e della Scienza University Hospital, Turin, Italy
| | - E Riberi
- Department of Public Health and Pediatrics, University of Torino, Turin, Italy
| | - E F Belligni
- Department of Public Health and Pediatrics, University of Torino, Turin, Italy
| | - E Biamino
- Department of Public Health and Pediatrics, University of Torino, Turin, Italy
| | - M Spielmann
- Research Group Mundlos, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - U Ala
- Computational Biology Unit, Molecular Biotechnology Center (MBC), Turin, Italy.,Department of Molecular Biotechnology and Health Sciences, University of Torino, Turin, Italy
| | - A Calcia
- University of Torino, Department of Medical Sciences, Turin, Italy
| | - I Bagnasco
- Neuropsichiatria Infantile, Martini Hospital, ASL TO1, Turin, Italy
| | - D Carli
- University of Torino, Department of Medical Sciences, Turin, Italy
| | - G Gai
- Medical Genetics Unit, Città della Salute e della Scienza University Hospital, Turin, Italy
| | - M Giordano
- Department of Health Sciences, Laboratory of Genetics, University of Eastern Piedmont and Interdisciplinary Research Center of Autoimmune Diseases, Novara, Italy
| | - A Guala
- SOC Pediatria, Castelli Hospital, Verbania, Italy
| | - R Keller
- Mental Health Department, ASL TO2, Adult Autism Center, Turin, Italy
| | - G Mandrile
- Medical Genetics Unit, Città della Salute e della Scienza University Hospital, Turin, Italy.,Medical Genetics, San Luigi Gonzaga University Hospital, Orbassano (TO), Italy
| | - C Arduino
- Medical Genetics Unit, Città della Salute e della Scienza University Hospital, Turin, Italy
| | - A Maffè
- Molecular Biology and Genetics Unit, Santa Croce e Carle Hospital, Cuneo, Italy
| | - V G Naretto
- Medical Genetics Unit, Città della Salute e della Scienza University Hospital, Turin, Italy
| | - F Sirchia
- Molecular Biology and Genetics Unit, Santa Croce e Carle Hospital, Cuneo, Italy
| | - L Sorasio
- Pediatrics, Santa Croce e Carle Hospital, Cuneo, Italy
| | - S Ungari
- Molecular Biology and Genetics Unit, Santa Croce e Carle Hospital, Cuneo, Italy
| | - A Zonta
- Medical Genetics Unit, Città della Salute e della Scienza University Hospital, Turin, Italy
| | - G Zacchetti
- Medical Genetics Unit, Città della Salute e della Scienza University Hospital, Turin, Italy.,Department of Health Sciences, Laboratory of Genetics, University of Eastern Piedmont and Interdisciplinary Research Center of Autoimmune Diseases, Novara, Italy
| | - F Talarico
- Medical Genetics Unit, Città della Salute e della Scienza University Hospital, Turin, Italy
| | - P Pappi
- Medical Genetics Unit, Città della Salute e della Scienza University Hospital, Turin, Italy
| | - S Cavalieri
- University of Torino, Department of Medical Sciences, Turin, Italy
| | - E Giorgio
- University of Torino, Department of Medical Sciences, Turin, Italy
| | - C Mancini
- University of Torino, Department of Medical Sciences, Turin, Italy
| | - M Ferrero
- University of Torino, Department of Medical Sciences, Turin, Italy
| | - A Brussino
- University of Torino, Department of Medical Sciences, Turin, Italy
| | - E Savin
- Medical Genetics Unit, Città della Salute e della Scienza University Hospital, Turin, Italy
| | - M Gandione
- Department of Neuropsychiatry, University of Torino, Turin, Italy
| | - A Pelle
- Medical Genetics, San Luigi Gonzaga University Hospital, Orbassano (TO), Italy.,Department of Clinical and Biological Sciences, University of Torino, Turin, Italy
| | - D F Giachino
- Medical Genetics, San Luigi Gonzaga University Hospital, Orbassano (TO), Italy.,Department of Clinical and Biological Sciences, University of Torino, Turin, Italy
| | - M De Marchi
- Medical Genetics, San Luigi Gonzaga University Hospital, Orbassano (TO), Italy.,Department of Clinical and Biological Sciences, University of Torino, Turin, Italy
| | - G Restagno
- Laboratory of Molecular Genetics, Città della Salute e della Scienza University Hospital, Turin, Italy
| | - P Provero
- Computational Biology Unit, Molecular Biotechnology Center (MBC), Turin, Italy.,Department of Molecular Biotechnology and Health Sciences, University of Torino, Turin, Italy
| | - M Cirillo Silengo
- Department of Public Health and Pediatrics, University of Torino, Turin, Italy
| | - E Grosso
- Medical Genetics Unit, Città della Salute e della Scienza University Hospital, Turin, Italy
| | - J D Buxbaum
- Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, New York.,Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, New York.,Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York.,Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York.,Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York.,Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - B Pasini
- Molecular Biology and Genetics Unit, Santa Croce e Carle Hospital, Cuneo, Italy
| | - S De Rubeis
- Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, New York.,Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, New York
| | - A Brusco
- University of Torino, Department of Medical Sciences, Turin, Italy.,Medical Genetics Unit, Città della Salute e della Scienza University Hospital, Turin, Italy
| | - G B Ferrero
- Department of Public Health and Pediatrics, University of Torino, Turin, Italy
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9
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Giorgio E, Brussino A, Biamino E, Belligni EF, Bruselles A, Ciolfi A, Caputo V, Pizzi S, Calcia A, Di Gregorio E, Cavalieri S, Mancini C, Pozzi E, Ferrero M, Riberi E, Borelli I, Amoroso A, Ferrero GB, Tartaglia M, Brusco A. Exome sequencing in children of women with skewed X-inactivation identifies atypical cases and complex phenotypes. Eur J Paediatr Neurol 2017; 21:475-484. [PMID: 28027854 DOI: 10.1016/j.ejpn.2016.12.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 11/03/2016] [Accepted: 12/11/2016] [Indexed: 12/30/2022]
Abstract
BACKGROUND More than 100 X-linked intellectual disability (X-LID) genes have been identified to be involved in 10-15% of intellectual disability (ID). METHOD To identify novel possible candidates, we selected 18 families with a male proband affected by isolated or syndromic ID. Pedigree and/or clinical presentation suggested an X-LID disorder. After exclusion of known genetic diseases, we identified seven cases whose mother showed a skewed X-inactivation (>80%) that underwent whole exome sequencing (WES, 50X average depth). RESULTS WES allowed to solve the genetic basis in four cases, two of which (Coffin-Lowry syndrome, RPS6K3 gene; ATRX syndrome, ATRX gene) had been missed by previous clinical/genetics tests. One further ATRX case showed a complex phenotype including pontocerebellar atrophy (PCA), possibly associated to an unidentified PCA gene mutation. In a case with suspected Lujan-Fryns syndrome, a c.649C>T (p.Pro217Ser) MECP2 missense change was identified, likely explaining the neurological impairment, but not the marfanoid features, which were possibly associated to the p.Thr1020Ala variant in fibrillin 1. Finally, a c.707T>G variant (p.Phe236Cys) in the DMD gene was identified in a patient retrospectively recognized to be affected by Becker muscular dystrophy (BMD, OMIM 300376). CONCLUSION Overall, our data show that WES may give hints to solve complex ID phenotypes with a likely X-linked transmission, and that a significant proportion of these orphan conditions might result from concomitant mutations affecting different clinically associated genes.
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Affiliation(s)
- Elisa Giorgio
- University of Torino, Department of Medical Sciences, 10126, Turin, Italy
| | | | - Elisa Biamino
- University of Torino, Department of Public Health and Pediatrics, 10126, Turin, Italy
| | - Elga Fabia Belligni
- University of Torino, Department of Public Health and Pediatrics, 10126, Turin, Italy
| | - Alessandro Bruselles
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù IRCSS, Rome, Italy
| | - Andrea Ciolfi
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù IRCSS, Rome, Italy
| | - Viviana Caputo
- Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy
| | - Simone Pizzi
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù IRCSS, Rome, Italy
| | - Alessandro Calcia
- University of Torino, Department of Medical Sciences, 10126, Turin, Italy
| | - Eleonora Di Gregorio
- University of Torino, Department of Medical Sciences, 10126, Turin, Italy; Città della Salute e della Scienza University Hospital, Medical Genetics Unit, Turin, Italy
| | - Simona Cavalieri
- University of Torino, Department of Medical Sciences, 10126, Turin, Italy
| | - Cecilia Mancini
- University of Torino, Department of Medical Sciences, 10126, Turin, Italy
| | - Elisa Pozzi
- University of Torino, Department of Medical Sciences, 10126, Turin, Italy
| | - Marta Ferrero
- University of Torino, Department of Medical Sciences, 10126, Turin, Italy
| | - Evelise Riberi
- University of Torino, Department of Public Health and Pediatrics, 10126, Turin, Italy
| | - Iolanda Borelli
- University of Torino, Department of Medical Sciences, 10126, Turin, Italy
| | - Antonio Amoroso
- University of Torino, Department of Medical Sciences, 10126, Turin, Italy
| | | | - Marco Tartaglia
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù IRCSS, Rome, Italy
| | - Alfredo Brusco
- University of Torino, Department of Medical Sciences, 10126, Turin, Italy; Città della Salute e della Scienza University Hospital, Medical Genetics Unit, Turin, Italy.
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10
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Di Gregorio E, Gai G, Botta G, Calcia A, Pappi P, Talarico F, Savin E, Ribotta M, Zonta A, Mancini C, Giorgio E, Cavalieri S, Restagno G, Ferrero GB, Viora E, Pasini B, Grosso E, Brusco A, Brussino A. Array-Comparative Genomic Hybridization Analysis in Fetuses with Major Congenital Malformations Reveals that 24% of Cases Have Pathogenic Deletions/Duplications. Cytogenet Genome Res 2015; 147:10-6. [PMID: 26658296 DOI: 10.1159/000442308] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/19/2015] [Indexed: 11/19/2022] Open
Abstract
Karyotyping and aCGH are routinely used to identify genetic determinants of major congenital malformations (MCMs) in fetal deaths or terminations of pregnancy after prenatal diagnosis. Pathogenic rearrangements are found with a variable rate of 9-39% for aCGH. We collected 33 fetuses, 9 with a single MCM and 24 with MCMs involving 2-4 organ systems. aCGH revealed copy number variants in 14 out of 33 cases (42%). Eight were classified as pathogenic which account for a detection rate of 24% (8/33) considering fetuses with 1 or more MCMs and 33% (8/24) taking into account fetuses with multiple malformations only. Three of the pathogenic variants were known microdeletion syndromes (22q11.21 deletion, central chromosome 22q11.21 deletion, and TAR syndrome) and 5 were large rearrangements, adding up to >11 Mb per subject and comprising strong phenotype-related genes. One of those was a de novo complex rearrangement, and the remaining 4 duplications and 2 deletions were 130-900 kb in size, containing 1-7 genes, and were classified as variants of unknown clinical significance. Our study confirms aCGH as a powerful technique to ascertain the genetic etiology of fetal major congenital malformations.
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11
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Giorgio E, Robyr D, Spielmann M, Ferrero E, Di Gregorio E, Imperiale D, Vaula G, Stamoulis G, Santoni F, Atzori C, Gasparini L, Ferrera D, Canale C, Guipponi M, Pennacchio LA, Antonarakis SE, Brussino A, Brusco A. A large genomic deletion leads to enhancer adoption by the lamin B1 gene: a second path to autosomal dominant adult-onset demyelinating leukodystrophy (ADLD). Hum Mol Genet 2015; 24:3143-54. [PMID: 25701871 PMCID: PMC4424952 DOI: 10.1093/hmg/ddv065] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 02/13/2015] [Indexed: 01/23/2023] Open
Abstract
Chromosomal rearrangements with duplication of the lamin B1 (LMNB1) gene underlie autosomal dominant adult-onset demyelinating leukodystrophy (ADLD), a rare neurological disorder in which overexpression of LMNB1 causes progressive central nervous system demyelination. However, we previously reported an ADLD family (ADLD-1-TO) without evidence of duplication or other mutation in LMNB1 despite linkage to the LMNB1 locus and lamin B1 overexpression. By custom array-CGH, we further investigated this family and report here that patients carry a large (∼660 kb) heterozygous deletion that begins 66 kb upstream of the LMNB1 promoter. Lamin B1 overexpression was confirmed in further ADLD-1-TO tissues and in a postmortem brain sample, where lamin B1 was increased in the frontal lobe. Through parallel studies, we investigated both loss of genetic material and chromosomal rearrangement as possible causes of LMNB1 overexpression, and found that ADLD-1-TO plausibly results from an enhancer adoption mechanism. The deletion eliminates a genome topological domain boundary, allowing normally forbidden interactions between at least three forebrain-directed enhancers and the LMNB1 promoter, in line with the observed mainly cerebral localization of lamin B1 overexpression and myelin degeneration. This second route to LMNB1 overexpression and ADLD is a new example of the relevance of regulatory landscape modifications in determining Mendelian phenotypes.
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Affiliation(s)
- Elisa Giorgio
- Department of Medical Sciences, University of Torino, via Santena, 19, Torino 10126, Italy
| | - Daniel Robyr
- Department of Genetic Medicine and Development, University of Geneva Medical School, Geneva 1211, Switzerland
| | - Malte Spielmann
- Max Planck Institute for Molecular Genetics, Ihnestr. 63-73, Berlin 14195, Germany
| | - Enza Ferrero
- Department of Medical Sciences, University of Torino, via Santena, 19, Torino 10126, Italy
| | - Eleonora Di Gregorio
- Department of Medical Sciences, University of Torino, via Santena, 19, Torino 10126, Italy Medical Genetics Unit and
| | - Daniele Imperiale
- Centro Regionale Malattie Da Prioni - Domp (ASLTO2), Torino 10144, Italy
| | - Giovanna Vaula
- Department of Neurology, Città della Salute e della Scienza University Hospital, Torino 10126, Italy
| | - Georgios Stamoulis
- Department of Genetic Medicine and Development, University of Geneva Medical School, Geneva 1211, Switzerland
| | - Federico Santoni
- Department of Genetic Medicine and Development, University of Geneva Medical School, Geneva 1211, Switzerland
| | - Cristiana Atzori
- Centro Regionale Malattie Da Prioni - Domp (ASLTO2), Torino 10144, Italy
| | | | | | - Claudio Canale
- Department of Nanophysics, Istituto Italiano di Tecnologia, Genoa 16163, Italy and
| | - Michel Guipponi
- Department of Genetic Medicine and Development, University of Geneva Medical School, Geneva 1211, Switzerland
| | - Len A Pennacchio
- Genomics Division, Lawrence Berkeley National Laboratory, MS 84-171, Berkeley, CA 9472, USA
| | - Stylianos E Antonarakis
- Department of Genetic Medicine and Development, University of Geneva Medical School, Geneva 1211, Switzerland
| | - Alessandro Brussino
- Department of Medical Sciences, University of Torino, via Santena, 19, Torino 10126, Italy
| | - Alfredo Brusco
- Department of Medical Sciences, University of Torino, via Santena, 19, Torino 10126, Italy Medical Genetics Unit and
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12
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Giorgio E, Vaula G, Bosco G, Giacone S, Mancini C, Calcia A, Cavalieri S, Di Gregorio E, Rigault De Longrais R, Leombruni S, Pinessi L, Cerrato P, Brusco A, Brussino A. Two families with novel missense mutations in COL4A1: When diagnosis can be missed. J Neurol Sci 2015; 352:99-104. [PMID: 25873210 DOI: 10.1016/j.jns.2015.03.042] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 02/25/2015] [Accepted: 03/26/2015] [Indexed: 12/17/2022]
Abstract
Mutations in COL4A1, encoding one of the six collagen type IV proteins, cover a wide spectrum of autosomal dominant overlapping phenotypes including porencephaly, small-vessel disease and hemorrhagic stroke, leukoencephalopathy, hereditary angiopathy with nephropathy, aneurysms and muscle cramp (HANAC) syndrome, and Walker-Warburg syndrome. Over 50 mutations are known, mainly being missense changes. Intra- and inter-familial variability has been reported. We studied two Italian families in which the proband had a clinical diagnosis of COL4A1-related disorder. We found two novel mutations (c.1249G>C; p.Gly417Arg and c.2662G>C; p.Gly888Arg). Both involved highly conserved amino acids and were predicted as being deleterious by bioinformatics tools. The c.1249G>C (p.Gly417Arg) segregated in four subjects with variable neurological phenotypes, namely leukoencephalopathy with muscle symptoms, brain small-vessel disease, and mild infantile encephalopathy. A fourth case was a carrier of the mutation without any neurological symptoms and an MRI with a specific white matter anomaly. The c.2662G>C (p.Gly888Arg) mutation was de novo in the proband. After a temporary motor impairment at age 14, the subject complained of mild imbalance at age 30, during the third trimester of her twin pregnancy, when an anomaly of the left brain hemisphere was documented in one fetus. Both her male dizygotic twins presented a severe motor delay, early convulsions, and leukoencephalopathy, and were carriers of the mutation. In summary, we confirm that high intra-familial variability of COL4A1 mutations with very mild phenotypes, the apparent incomplete penetrance, and de novo changes may become a "dilemma" for clinicians and genetic counselors.
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Affiliation(s)
- Elisa Giorgio
- University of Torino, Department of Medical Sciences, Torino 10126, Italy
| | - Giovanna Vaula
- Città della Salute e della Scienza University Hospital, Department of Neuroscience, Torino 10126, Italy
| | - Giovanni Bosco
- Civil Hospital of Alba, Department of Neurology, Alba 12051, Italy
| | - Sara Giacone
- Città della Salute e della Scienza University Hospital, Department of Neuroscience, Torino 10126, Italy
| | - Cecilia Mancini
- University of Torino, Department of Medical Sciences, Torino 10126, Italy
| | - Alessandro Calcia
- University of Torino, Department of Medical Sciences, Torino 10126, Italy
| | - Simona Cavalieri
- Città della Salute e della Scienza University Hospital, Medical Genetics Unit, Torino 10126, Italy
| | - Eleonora Di Gregorio
- Città della Salute e della Scienza University Hospital, Medical Genetics Unit, Torino 10126, Italy
| | | | - Sabrina Leombruni
- Città della Salute e della Scienza University Hospital, Department of Neuroscience, Torino 10126, Italy
| | - Lorenzo Pinessi
- Città della Salute e della Scienza University Hospital, Department of Neuroscience, Torino 10126, Italy; University of Torino, Department of Neuroscience, Torino 10126, Italy
| | - Paolo Cerrato
- Città della Salute e della Scienza University Hospital, Department of Neuroscience, Torino 10126, Italy
| | - Alfredo Brusco
- University of Torino, Department of Medical Sciences, Torino 10126, Italy; Città della Salute e della Scienza University Hospital, Medical Genetics Unit, Torino 10126, Italy.
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13
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Mancini C, Nassani S, Guo Y, Chen Y, Giorgio E, Brussino A, Di Gregorio E, Cavalieri S, Lo Buono N, Funaro A, Pizio NR, Nmezi B, Kyttala A, Santorelli FM, Padiath QS, Hakonarson H, Zhang H, Brusco A. Adult-onset autosomal recessive ataxia associated with neuronal ceroid lipofuscinosis type 5 gene (CLN5) mutations. J Neurol 2015; 262:173-8. [PMID: 25359263 DOI: 10.1007/s00415-014-7553-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 10/17/2014] [Accepted: 10/18/2014] [Indexed: 12/01/2022]
Abstract
Autosomal recessive inherited ataxias are a growing group of genetic disorders. We report two Italian siblings presenting in their mid-50s with difficulty in walking, dysarthria and progressive cognitive decline. Visual loss, ascribed to glaucoma, manifested a few years before the other symptoms. Brain MRI showed severe cerebellar atrophy, prevalent in the vermis, with marked cortical atrophy of both hemispheres. Exome sequencing identified a novel homozygous mutation (c.935G > A;p.Ser312Asn) in the ceroid neuronal lipofuscinosis type 5 gene (CLN5). Bioinformatics predictions and in vitro studies showed that the mutation was deleterious and likely affects ER-lysosome protein trafficking. Our findings support CLN5 hypomorphic mutations cause autosomal recessive cerebellar ataxia, confirming other reports showing CLN mutations are associated with adult-onset neurodegenerative disorders. We suggest CLN genes should be considered in the molecular analyses of patients presenting with adult-onset autosomal recessive cerebellar ataxia.
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Affiliation(s)
- Cecilia Mancini
- Department of Medical Sciences, University of Torino, Via Santena 19, 10126, Turin, Italy
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14
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Tezenas du Montcel S, Durr A, Bauer P, Figueroa KP, Ichikawa Y, Brussino A, Forlani S, Rakowicz M, Schöls L, Mariotti C, van de Warrenburg BPC, Orsi L, Giunti P, Filla A, Szymanski S, Klockgether T, Berciano J, Pandolfo M, Boesch S, Melegh B, Timmann D, Mandich P, Camuzat A, Goto J, Ashizawa T, Cazeneuve C, Tsuji S, Pulst SM, Brusco A, Riess O, Brice A, Stevanin G. Modulation of the age at onset in spinocerebellar ataxia by CAG tracts in various genes. ACTA ACUST UNITED AC 2014; 137:2444-55. [PMID: 24972706 DOI: 10.1093/brain/awu174] [Citation(s) in RCA: 121] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Polyglutamine-coding (CAG)n repeat expansions in seven different genes cause spinocerebellar ataxias. Although the size of the expansion is negatively correlated with age at onset, it accounts for only 50-70% of its variability. To find other factors involved in this variability, we performed a regression analysis in 1255 affected individuals with identified expansions (spinocerebellar ataxia types 1, 2, 3, 6 and 7), recruited through the European Consortium on Spinocerebellar Ataxias, to determine whether age at onset is influenced by the size of the normal allele in eight causal (CAG)n-containing genes (ATXN1-3, 6-7, 17, ATN1 and HTT). We confirmed the negative effect of the expanded allele and detected threshold effects reflected by a quadratic association between age at onset and CAG size in spinocerebellar ataxia types 1, 3 and 6. We also evidenced an interaction between the expanded and normal alleles in trans in individuals with spinocerebellar ataxia types 1, 6 and 7. Except for individuals with spinocerebellar ataxia type 1, age at onset was also influenced by other (CAG)n-containing genes: ATXN7 in spinocerebellar ataxia type 2; ATXN2, ATN1 and HTT in spinocerebellar ataxia type 3; ATXN1 and ATXN3 in spinocerebellar ataxia type 6; and ATXN3 and TBP in spinocerebellar ataxia type 7. This suggests that there are biological relationships among these genes. The results were partially replicated in four independent populations representing 460 Caucasians and 216 Asian samples; the differences are possibly explained by ethnic or geographical differences. As the variability in age at onset is not completely explained by the effects of the causative and modifier sister genes, other genetic or environmental factors must also play a role in these diseases.
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Affiliation(s)
- Sophie Tezenas du Montcel
- 1 Sorbonne Universités, Université Pierre et Marie Curie (UPMC) Univ Paris 06, UMR_S 1136, Institut Pierre Louis d'Epidémiologie et de Santé Publique, F-75013, Paris, France2 INSERM, UMR_S 1136, Institut Pierre Louis d'Epidémiologie et de Santé Publique, F-75013, Paris, France3 AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Biostatistics Unit, Paris, F-75013, France
| | - Alexandra Durr
- 4 AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Department of Genetics and Cytogenetics, F-75013, Paris, France5 Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, F-75013, Paris, France
| | - Peter Bauer
- 6 Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
| | - Karla P Figueroa
- 7 Department of Neurology, University of Utah, Salt Lake City, USA
| | - Yaeko Ichikawa
- 8 Department of Neurology, University of Tokyo, Graduate School of Medicine, Tokyo, Japan
| | - Alessandro Brussino
- 9 University of Torino, Department of Medical Sciences, and Medical Genetics Unit, Az. Osp. 'Città della Salute e della Scienza', Torino, Italy
| | - Sylvie Forlani
- 5 Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, F-75013, Paris, France
| | - Maria Rakowicz
- 10 Institute of Psychiatry and Neurology Warsaw, Sobieskiego 9, 02-957 Warsaw, Poland
| | - Ludger Schöls
- 11 Department of Neurology and Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany12 German Centre of Neurodegenerative Diseases (DZNE), Tübingen, Germany
| | - Caterina Mariotti
- 13 SOSD Unit of Genetics of Neurodegenerative and Metabolic Diseases, Fondazione IRCCS, Istituto Neurologico 'Carlo Besta', Milan, Italy
| | - Bart P C van de Warrenburg
- 14 Department of Neurology, Donders Institute for Brain, Cognition, and Behaviour, Radbound University Medical Centre, Nijmegen, The Netherlands
| | - Laura Orsi
- 15 Neurologic Division I, Department of Neuroscience and Mental Health, AOU Città della Salute e della Scienza, Torino, Italy
| | - Paola Giunti
- 16 Institute of Neurology, Department of Molecular Neuroscience, UCL, Queen Square, London, UK
| | - Alessandro Filla
- 17 Department of Neurological Sciences, Federico II University, Naples, Italy
| | - Sandra Szymanski
- 18 Department of Neurology, St. Josef Hospital, University Hospital of Bochum, Bochum, Germany
| | | | - José Berciano
- 20 Department of Neurology, University Hospital 'Marqués de Valdecilla', UC, IDIVAL and CIBERNED, 39008 Santander, Spain
| | - Massimo Pandolfo
- 21 Department of Neurology, ULB-Hôpital Erasme, Université Libre de Bruxelles, CP 231, Campus Plaine, ULB, Brusssels, Belgium
| | - Sylvia Boesch
- 22 Department of Neurology, Medical University Innsbruck, Innsbruck, Austria
| | - Bela Melegh
- 23 Department of Medical Genetics, and Szentagothai Research Centre, University Pécs, Hungary
| | - Dagmar Timmann
- 24 Department of Neurology, University Clinic Essen, University of Duisburg-Essen, Essen, Germany
| | - Paola Mandich
- 25 Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics and Maternal Child Health, University of Genova, and U.O. Medical Genetics of IRCCS AOU S. Martino Institute, Genova, Italy
| | - Agnès Camuzat
- 5 Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, F-75013, Paris, France
| | | | | | - Jun Goto
- 8 Department of Neurology, University of Tokyo, Graduate School of Medicine, Tokyo, Japan
| | - Tetsuo Ashizawa
- 26 Department of Neurology and McKnight Brain Institute, University of Florida, Gainesville, Florida, USA
| | - Cécile Cazeneuve
- 4 AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Department of Genetics and Cytogenetics, F-75013, Paris, France
| | - Shoji Tsuji
- 8 Department of Neurology, University of Tokyo, Graduate School of Medicine, Tokyo, Japan
| | - Stefan-M Pulst
- 7 Department of Neurology, University of Utah, Salt Lake City, USA
| | - Alfredo Brusco
- 9 University of Torino, Department of Medical Sciences, and Medical Genetics Unit, Az. Osp. 'Città della Salute e della Scienza', Torino, Italy
| | - Olaf Riess
- 6 Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
| | - Alexis Brice
- 4 AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Department of Genetics and Cytogenetics, F-75013, Paris, France5 Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, F-75013, Paris, France
| | - Giovanni Stevanin
- 4 AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Department of Genetics and Cytogenetics, F-75013, Paris, France5 Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, F-75013, Paris, France27 Ecole Pratique des Hautes Etudes, heSam Université, laboratoire de neurogénétique, ICM, Groupe Hospitalier Pitié-Salpêtrière, F-75013 Paris, France
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15
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Giorgio E, Rolyan H, Kropp L, Chakka AB, Yatsenko S, Gregorio ED, Lacerenza D, Vaula G, Talarico F, Mandich P, Toro C, Pierre EE, Labauge P, Capellari S, Cortelli P, Vairo FP, Miguel D, Stubbolo D, Marques LC, Gahl W, Boespflug-Tanguy O, Melberg A, Hassin-Baer S, Cohen OS, Pjontek R, Grau A, Klopstock T, Fogel B, Meijer I, Rouleau G, Bouchard JPL, Ganapathiraju M, Vanderver A, Dahl N, Hobson G, Brusco A, Brussino A, Padiath QS. Analysis ofLMNB1Duplications in Autosomal Dominant Leukodystrophy Provides Insights into Duplication Mechanisms and Allele-Specific Expression. Hum Mutat 2013. [DOI: 10.1002/humu.22466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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16
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Giorgio E, Rolyan H, Kropp L, Chakka AB, Yatsenko S, Gregorio ED, Lacerenza D, Vaula G, Talarico F, Mandich P, Toro C, Pierre EE, Labauge P, Capellari S, Cortelli P, Vairo FP, Miguel D, Stubbolo D, Marques LC, Gahl W, Boespflug-Tanguy O, Melberg A, Hassin-Baer S, Cohen OS, Pjontek R, Grau A, Klopstock T, Fogel B, Meijer I, Rouleau G, Bouchard JPL, Ganapathiraju M, Vanderver A, Dahl N, Hobson G, Brusco A, Brussino A, Padiath QS. Analysis of LMNB1 duplications in autosomal dominant leukodystrophy provides insights into duplication mechanisms and allele-specific expression. Hum Mutat 2013; 34:1160-71. [PMID: 23649844 PMCID: PMC3714349 DOI: 10.1002/humu.22348] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Accepted: 04/19/2013] [Indexed: 02/05/2023]
Abstract
Autosomal dominant leukodystrophy (ADLD) is an adult onset demyelinating disorder that is caused by duplications of the lamin B1 (LMNB1) gene. However, as only a few cases have been analyzed in detail, the mechanisms underlying LMNB1 duplications are unclear. We report the detailed molecular analysis of the largest collection of ADLD families studied, to date. We have identified the minimal duplicated region necessary for the disease, defined all the duplication junctions at the nucleotide level and identified the first inverted LMNB1 duplication. We have demonstrated that the duplications are not recurrent; patients with identical duplications share the same haplotype, likely inherited from a common founder and that the duplications originated from intrachromosomal events. The duplication junction sequences indicated that nonhomologous end joining or replication-based mechanisms such fork stalling and template switching or microhomology-mediated break induced repair are likely to be involved. LMNB1 expression was increased in patients' fibroblasts both at mRNA and protein levels and the three LMNB1 alleles in ADLD patients show equal expression, suggesting that regulatory regions are maintained within the rearranged segment. These results have allowed us to elucidate duplication mechanisms and provide insights into allele-specific LMNB1 expression levels.
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Affiliation(s)
- Elisa Giorgio
- University of Torino, Department of Medical SciencesTorino, Italy
| | - Harshvardhan Rolyan
- Department of Human Genetics Graduate School of Public Health, University of PittsburghPittsburgh, Pennsylvania
| | - Laura Kropp
- Department of Human Genetics Graduate School of Public Health, University of PittsburghPittsburgh, Pennsylvania
| | - Anish Baswanth Chakka
- Department of Biomedical Informatics School of Medicine, University of PittsburghPittsburgh, Pennsylvania
| | - Svetlana Yatsenko
- Department of Obstetrics Gynecology and Reproductive Sciences, University of PittsburghPittsburgh, Pennsylvania
- Department of Pathology University of Pittsburgh, School of MedicinePittsburgh, Pennsylvania
| | - Eleonora Di Gregorio
- University of Torino, Department of Medical SciencesTorino, Italy
- S.C.D.U. Medical Genetics, Az. Osp. Città della Salute e della ScienzaTorino, Italy
| | | | - Giovanna Vaula
- Department of Neuroscience, Az. Osp. Città della Salute e della ScienzaTorino, Italy
| | - Flavia Talarico
- S.C.D.U. Medical Genetics, Az. Osp. Città della Salute e della ScienzaTorino, Italy
| | - Paola Mandich
- Department of Neurology, Ophthalmology and Genetics, di Bologna, Department of Biomedical and NeuroMotor Sciences (DIBINEM) Alma Mater StudiorumBologna, Italy
| | - Camilo Toro
- NIH Undiagnosed Diseases Program NIH Office of Rare Disease, Research and NHGRIBethesda, Maryland
| | | | - Pierre Labauge
- Neurologie Hopital Caremeau, Centre Hospitalo-Universitaire de NimesNimes, France
| | - Sabina Capellari
- University of Bologna IRCCS Istituto delle Scienze Neurologiche di Bologna Department of Biomedical and NeuroMotor Sciences (DIBINEM), Alma Mater StudiorumItaly
| | - Pietro Cortelli
- University of Bologna IRCCS Istituto delle Scienze Neurologiche di Bologna Department of Biomedical and NeuroMotor Sciences (DIBINEM), Alma Mater StudiorumItaly
| | - Filippo Pinto Vairo
- Hospital de Clínicas de Porto Alegre … Universidade Federal do Rio Grande do SulPorto Alegre, Brazil
| | - Diego Miguel
- Hospital de Clínicas de Porto Alegre … Universidade Federal do Rio Grande do SulPorto Alegre, Brazil
| | - Danielle Stubbolo
- Nemours Biomedical Research, Alfred I. duPont Hospital for ChildrenWilmington, Delaware
| | - Lourenco Charles Marques
- Department of Medical Genetics Clinics Hospital of Ribeirao Preto, University of Sao PauloSao Paulo, Brazil
| | - William Gahl
- NIH Undiagnosed Diseases Program NIH Office of Rare Disease, Research and NHGRIBethesda, Maryland
| | - Odile Boespflug-Tanguy
- Institut National de la Santé et de la Recherche Médicale (INSERM) – Paris Diderot Sorbonne Paris Cité University, Robert Debré HospitalParis, France
- Assistance Publique des Hopitaux de Paris Reference Center for Rare Diseases “Leukodystrophies”, Child Neurology and Metabolic Disorders DepartmentParis, France
| | - Atle Melberg
- Department of Neuroscience Neurology, Uppsala UniversityUppsala, Sweden
| | - Sharon Hassin-Baer
- Parkinson’s disease and Movement Disorders Clinic Department of Neurology, Chaim Sheba Medical CenterTel Aviv, Israel
- Sackler Faculty of Medicine, Tel Aviv UniversityTel Aviv, Israel
| | - Oren S Cohen
- Parkinson’s disease and Movement Disorders Clinic Department of Neurology, Chaim Sheba Medical CenterTel Aviv, Israel
- Sackler Faculty of Medicine, Tel Aviv UniversityTel Aviv, Israel
| | - Rastislav Pjontek
- Department of Neurology, University of HeidelbergHeidelberg, Germany
| | - Armin Grau
- Dept. of Neurology, Klinikum LudwigshafenLudwigshafen, Germany
| | - Thomas Klopstock
- Dept. of Neurology Friedrich-Baur-Institute, Ludwig-Maximilians-UniversityMunich, Germany
- German Center for Vertigo and Balance DisordersMunich, Germany
- DZNE – German Center for Neurodegenerative DiseasesMunich, Germany
- German Network for Mitochondrial Disorders(mitoNET), Germany
| | - Brent Fogel
- Department of Neurology David Geffen School of Medicine, University of CaliforniaLos Angeles, California
| | - Inge Meijer
- Montreal Neurological Institute, McGill UniversityMontreal, Canada
| | - Guy Rouleau
- Montreal Neurological Institute, McGill UniversityMontreal, Canada
| | | | - Madhavi Ganapathiraju
- Department of Biomedical Informatics School of Medicine, University of PittsburghPittsburgh, Pennsylvania
| | - Adeline Vanderver
- Department of Neurology, Childrens National Medical CenterWashington, District of Columbia
| | - Niklas Dahl
- Dept. of Immunology Genetics and Pathology Section of Clinical Genetics The Rudbeck laboratory, Uppsala University Children’s HospitalUppsala, Sweden
| | - Grace Hobson
- Nemours Biomedical Research, Alfred I. duPont Hospital for ChildrenWilmington, Delaware
- University of Delaware, Department of BiologyNewark, Delaware
- Thomas Jefferson University, Jefferson Medical CollegePhiladelphia, Pennsylvania
| | - Alfredo Brusco
- University of Torino, Department of Medical SciencesTorino, Italy
- S.C.D.U. Medical Genetics, Az. Osp. Città della Salute e della ScienzaTorino, Italy
| | | | - Quasar Saleem Padiath
- Department of Human Genetics Graduate School of Public Health, University of PittsburghPittsburgh, Pennsylvania
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17
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Di Gregorio E, Bianchi FT, Schiavi A, Chiotto AMA, Rolando M, Verdun di Cantogno L, Grosso E, Cavalieri S, Calcia A, Lacerenza D, Zuffardi O, Retta SF, Stevanin G, Marelli C, Durr A, Forlani S, Chelly J, Montarolo F, Tempia F, Beggs HE, Reed R, Squadrone S, Abete MC, Brussino A, Ventura N, Di Cunto F, Brusco A. A de novo X;8 translocation creates a PTK2-THOC2 gene fusion with THOC2 expression knockdown in a patient with psychomotor retardation and congenital cerebellar hypoplasia. J Med Genet 2013; 50:543-51. [PMID: 23749989 DOI: 10.1136/jmedgenet-2013-101542] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
BACKGROUND AND AIM We identified a balanced de novo translocation involving chromosomes Xq25 and 8q24 in an eight year-old girl with a non-progressive form of congenital ataxia, cognitive impairment and cerebellar hypoplasia. METHODS AND RESULTS Breakpoint definition showed that the promoter of the Protein Tyrosine Kinase 2 (PTK2, also known as Focal Adhesion Kinase, FAK) gene on chromosome 8q24.3 is translocated 2 kb upstream of the THO complex subunit 2 (THOC2) gene on chromosome Xq25. PTK2 is a well-known non-receptor tyrosine kinase whereas THOC2 encodes a component of the evolutionarily conserved multiprotein THO complex, involved in mRNA export from nucleus. The translocation generated a sterile fusion transcript under the control of the PTK2 promoter, affecting expression of both PTK2 and THOC2 genes. PTK2 is involved in cell adhesion and, in neurons, plays a role in axonal guidance, and neurite growth and attraction. However, PTK2 haploinsufficiency alone is unlikely to be associated with human disease. Therefore, we studied the role of THOC2 in the CNS using three models: 1) THOC2 ortholog knockout in C.elegans which produced functional defects in specific sensory neurons; 2) Thoc2 knockdown in primary rat hippocampal neurons which increased neurite extension; 3) Thoc2 knockdown in neuronal stem cells (LC1) which increased their in vitro growth rate without modifying apoptosis levels. CONCLUSION We suggest that THOC2 can play specific roles in neuronal cells and, possibly in combination with PTK2 reduction, may affect normal neural network formation, leading to cognitive impairment and cerebellar congenital hypoplasia.
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18
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Mancini C, Vaula G, Scalzitti L, Cavalieri S, Bertini E, Aiello C, Lucchini C, Gatti RA, Brussino A, Brusco A. Megalencephalic leukoencephalopathy with subcortical cysts type 1 (MLC1) due to a homozygous deep intronic splicing mutation (c.895-226T>G) abrogated in vitro using an antisense morpholino oligonucleotide. Neurogenetics 2012; 13:205-14. [PMID: 22552818 DOI: 10.1007/s10048-012-0331-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Accepted: 04/16/2012] [Indexed: 11/24/2022]
Abstract
Megalencephalic leukoencephalopathy with subcortical cysts is an autosomal recessive disease characterized by early onset macrocephaly; developmental delay; motor disability in the form of progressive spasticity and ataxia; seizures; cognitive decline; and characteristic magnetic resonance imaging findings. Mutations in two genes, MLC1 (22q13.33; 75 % of patients) or HEPACAM (11q24; 20 % of patients), are associated with the disease. We describe an adult MLC patient with moderate clinical symptoms. MLC1 cDNA analysis from lymphoblasts showed a strong transcript reduction and identified a 246-bp pseudoexon containing a premature stop codon between exons 10 and 11, due to a homozygous c.895-226 T>G deep-intronic mutation. This category of mutations is often overlooked, being outside of canonically sequenced genomic regions. The mutation c.895-226 T>G has a leaky effect on splicing leaving part of the full-length transcript. Its role on splicing was confirmed using a minigene assay and an antisense morpholinated oligonucleotide targeted to the aberrant splice site in vitro, which partially abrogated the mutation effect.
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Affiliation(s)
- Cecilia Mancini
- Department of Genetics, Biology and Biochemistry, University of Torino, via Santena, 19-10126 Torino, Italy
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19
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Mancini C, Messana E, Turco E, Brussino A, Brusco A. Gene-targeted embryonic stem cells: real-time PCR assay for estimation of the number of neomycin selection cassettes. Biol Proced Online 2011; 13:10. [PMID: 22035318 PMCID: PMC3226651 DOI: 10.1186/1480-9222-13-10] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Accepted: 10/28/2011] [Indexed: 12/04/2022] Open
Abstract
In the preparation of transgenic murine ES cells it is important to verify the construct has a single insertion, because an ectopic neomycin phosphortransferase positive selection cassette (NEO) may cause a position effect. During a recent work, where a knockin SCA28 mouse was prepared, we developed two assays based on Real-Time PCR using both SYBR Green and specific minor groove binder (MGB) probes to evaluate the copies of NEO using the comparative delta-delta Ct method versus the Rpp30 reference gene. We compared the results from Southern blot, routinely used to quantify NEO copies, with the two Real-Time PCR assays. Twenty-two clones containing the single NEO copy showed values of 0.98 ± 0.24 (mean ± 2 S.D.), and were clearly distinguishable from clones with two or more NEO copies. This method was found to be useful, easy, sensitive and fast and could substitute for the widely used, but laborious Southern blot method.
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Affiliation(s)
- Cecilia Mancini
- Department of Genetics, Biology and Biochemistry, University of Torino, Torino, Italy.
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20
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Cagnoli C, Stevanin G, Brussino A, Barberis M, Mancini C, Margolis RL, Holmes SE, Nobili M, Forlani S, Padovan S, Pappi P, Zaros C, Leber I, Ribai P, Pugliese L, Assalto C, Brice A, Migone N, Dürr A, Brusco A. Missense mutations in the AFG3L2 proteolytic domain account for ∼1.5% of European autosomal dominant cerebellar ataxias. Hum Mutat 2011; 31:1117-24. [PMID: 20725928 DOI: 10.1002/humu.21342] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Spinocerebellar ataxia type 28 is an autosomal dominant form of cerebellar ataxia (ADCA) caused by mutations in AFG3L2, a gene that encodes a subunit of the mitochondrial m-AAA protease. We screened 366 primarily Caucasian ADCA families, negative for the most common triplet expansions, for point mutations in AFG3L2 using DHPLC. Whole-gene deletions were excluded in 300 of the patients, and duplications were excluded in 129 patients. We found six missense mutations in nine unrelated index cases (9/366, 2.6%): c.1961C>T (p.Thr654Ile) in exon 15, c.1996A>G (p.Met666Val), c.1997T>G (p.Met666Arg), c.1997T>C (p.Met666Thr), c.2011G>A (p.Gly671Arg), and c.2012G>A (p.Gly671Glu) in exon 16. All mutated amino acids were located in the C-terminal proteolytic domain. In available cases, we demonstrated the mutations segregated with the disease. Mutated amino acids are highly conserved, and bioinformatic analysis indicates the substitutions are likely deleterious. This investigation demonstrates that SCA28 accounts for ∼3% of ADCA Caucasian cases negative for triplet expansions and, in extenso, to ∼1.5% of all ADCA. We further confirm both the involvement of AFG3L2 gene in SCA28 and the presence of a mutational hotspot in exons 15-16. Screening for SCA28, is warranted in patients who test negative for more common SCAs and present with a slowly progressive cerebellar ataxia accompanied by oculomotor signs.
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Affiliation(s)
- Claudia Cagnoli
- Department of Genetics, Biology and Biochemistry, University of Torino, Torino, Italy
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21
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Brussino A, Graziano C, Giobbe D, Ferrone M, Dragone E, Arduino C, Lodi R, Tonon C, Gabellini A, Rinaldi R, Miccoli S, Grosso E, Bellati MC, Orsi L, Migone N, Brusco A. Spinocerebellar ataxia type 12 identified in two Italian families may mimic sporadic ataxia. Mov Disord 2010; 25:1269-73. [PMID: 20629122 DOI: 10.1002/mds.22835] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
SCA12 is an autosomal dominant cerebellar ataxia characterized by onset in the fourth decade of life with action tremor of arms and head, mild ataxia, dysmetria, and hyperreflexia. The disease is caused by an expansion of >or=51 CAGs in the 5' region of the brain- specific phosphatase 2 regulatory subunit B-beta isoform (PPP2R2B) gene. SCA12 is very rare, except for a single ethnic group in India. We screened 159 Italian ataxic patients for SCA12 and identified two families that segregated an expanded allele of 57 to 58 CAGs, sharing a common haplotype. The age at onset, phenotype, and variability of symptoms were compatible with known cases. In one family, the disease was apparently sporadic due to possible incomplete penetrance and/or late age at onset. Our data indicate that SCA12 is also present in Italian patients, and its genetic testing should be applied to both sporadic and familial ataxias.
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Affiliation(s)
- Alessandro Brussino
- Department of Genetics, Biology and Biochemistry, University of Torino, and S.C.D.U. Medical Genetics, A.O.U. San Giovanni Battista, Torino, Italy
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22
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Brussino A, Vaula G, Cagnoli C, Panza E, Seri M, Di Gregorio E, Scappaticci S, Camanini S, Daniele D, Bradac GB, Pinessi L, Cavalieri S, Grosso E, Migone N, Brusco A. A family with autosomal dominant leukodystrophy linked to 5q23.2-q23.3 without lamin B1 mutations. Eur J Neurol 2010; 17:541-9. [PMID: 19961535 DOI: 10.1111/j.1468-1331.2009.02844.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND AND PURPOSE Duplications of lamin B1 (LMNB1) at 5q23 are implicated in adult-onset autosomal dominant leukodystrophy (ADLD) having been described in six families with diverse ethnic background but with a homogeneous phenotype. In a large Italian family, we recently identified a variant form of ADLD characterized clinically by absence of the autonomic dysfunction at onset described in ADLD and, on MRI, by milder cerebellar involvement with sparing of hemispheric white matter. Aim of this study was to investigate the genetic basis of this variant form of ADLD. METHODS We carried out a genome-wide linkage analysis using microsatellite markers, and the genes in the candidate region were screened for point mutations. LMNB1 was also screened for deletions/duplications by real-time PCR, multiplex ligation-dependent probe amplification and Southern blot. RESULTS We mapped the variant ADLD locus to 5q23.2-q23.3, a genomic region containing 11 genes including LMNB1. Neither gene copy-number defects nor point mutations in the LMNB1 gene were found. We also excluded point mutations in the coding exons of the other ten genes in the candidate region. However, expression of lamin B1 evaluated in lymphoblastoid cells was higher in patients than in healthy controls, and was similar to the lamin B1 expression levels found in a patient with LMNB1 duplication. CONCLUSIONS This observation suggests that a mutation in an LMNB1 regulatory sequence underlies the variant ADLD phenotype. Thus, adult forms of ADLD linked to 5q23 appear to be more heterogeneous clinically and genetically than previously thought.
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Affiliation(s)
- A Brussino
- Department of Genetics, Biology and Biochemistry, University of Torino, and SCDU.Medical Genetics, AOU San Giovanni Battista, Torino, Italy
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23
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Di Bella D, Lazzaro F, Brusco A, Plumari M, Battaglia G, Pastore A, Finardi A, Cagnoli C, Tempia F, Frontali M, Veneziano L, Sacco T, Boda E, Brussino A, Bonn F, Castellotti B, Baratta S, Mariotti C, Gellera C, Fracasso V, Magri S, Langer T, Plevani P, Di Donato S, Muzi-Falconi M, Taroni F. Mutations in the mitochondrial protease gene AFG3L2 cause dominant hereditary ataxia SCA28. Nat Genet 2010; 42:313-21. [PMID: 20208537 DOI: 10.1038/ng.544] [Citation(s) in RCA: 236] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2009] [Accepted: 02/05/2010] [Indexed: 01/04/2023]
Abstract
Autosomal dominant spinocerebellar ataxias (SCAs) are genetically heterogeneous neurological disorders characterized by cerebellar dysfunction mostly due to Purkinje cell degeneration. Here we show that AFG3L2 mutations cause SCA type 28. Along with paraplegin, which causes recessive spastic paraplegia, AFG3L2 is a component of the conserved m-AAA metalloprotease complex involved in the maintenance of the mitochondrial proteome. We identified heterozygous missense mutations in five unrelated SCA families and found that AFG3L2 is highly and selectively expressed in human cerebellar Purkinje cells. m-AAA-deficient yeast cells expressing human mutated AFG3L2 homocomplex show respiratory deficiency, proteolytic impairment and deficiency of respiratory chain complex IV. Structure homology modeling indicates that the mutations may affect AFG3L2 substrate handling. This work identifies AFG3L2 as a novel cause of dominant neurodegenerative disease and indicates a previously unknown role for this component of the mitochondrial protein quality control machinery in protecting the human cerebellum against neurodegeneration.
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Affiliation(s)
- Daniela Di Bella
- Unit of Genetics of Neurodegenerative and Metabolic Diseases, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
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24
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Brussino A, D'Alfonso S, Cagnoli C, Di Gregorio E, Barberis M, Padovan S, Vaula G, Pinessi L, Squadrone S, Abete MC, Collimedaglia L, Guerini FR, Migone N, Brusco A. Mutations in the lamin B1 gene are not present in multiple sclerosis. Eur J Neurol 2009; 16:544-6. [PMID: 19348623 DOI: 10.1111/j.1468-1331.2009.02536.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Whole gene duplication of the lamin B1 gene (LMNB1), encoding for a protein of the nuclear lamina, causes an adult-onset autosomal dominant leukodystrophy (ADLD). Clinical features of ADLD (onset in adult life, dysautonomic symptoms, followed by pyramidal and cerebellar dysfunctions) partially resemble those of multiple sclerosis (MS), particularly the primary-progressive form. Our aim was to test whether LMNB1 gene mutations were present amongst patients with a diagnosis of MS. METHODS One hundred eighty-two MS patients were screened for copy number variations of the LMNB1 gene using a qPCR assay. Point mutations in the LMNB1 gene were searched by denaturing high-performance liquid chromatography and direct sequencing in a subgroup of 16 patients with familial MS. RESULTS No duplication/deletion of the lamin B1 gene was found amongst MS patients, and no point mutation was identified in the familial cases. CONCLUSION Our work indicates that lamin B1 defects are probably not responsible for signs and symptoms resembling multiple sclerosis.
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Affiliation(s)
- A Brussino
- Department of Genetics, Biology and Biochemistry, University of Torino, and S.C.D.U. Medical Genetics, A.O.U. San Giovanni Battista, Torino, Italy
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Brussino A, Vaula G, Cagnoli C, Mauro A, Pradotto L, Daniele D, Di Gregorio E, Barberis M, Arduino C, Squadrone S, Abete MC, Migone N, Calabrese O, Brusco A. A novel family with Lamin B1 duplication associated with adult-onset leucoencephalopathy. J Neurol Neurosurg Psychiatry 2009; 80:237-40. [PMID: 19151023 DOI: 10.1136/jnnp.2008.147330] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND AND AIMS Duplication of the lamin B1 gene (LMNB1) has recently been described in a rare form of autosomal dominant adult-onset leucoencephalopathy. The aim of the study was to evaluate the presence of LMNB1 gene defects in a series of eight patients with diffuse adult-onset hereditary leucoencephalopathy. METHODS Clinical features of tested patients included a variable combination of pyramidal, cerebellar, cognitive and autonomic dysfunction. Neuroradiological data (MRI) showed symmetrical and diffuse white-matter lesions in six cases, and multifocal confluent lesions in two. LMNB1 full gene deletion/duplication and point mutations were searched using a TaqMan real-time PCR assay and direct sequencing of all coding exons. RESULTS One patient carried a 140-190 kb duplication involving the entire LMNB1 gene, the AX748201 transcript and the 3' end of the MARCH3 gene. Clinical and neuroimaging data of this proband and an affected relative overlapped with the features already described in patients with LMNB1 duplication. Lamin B1 expression was found increased in lymphoblasts. No LMNB1 gene defect was identified in the remaining seven probands. CONCLUSIONS LMNB1 gene duplication appears characteristic of a subset of adult-onset autosomal dominant leucoencephalopathies, sharing autonomic dysfunction at onset, diffuse T2-hyperintensity of supra- and infratentorial white matter, sparing of U-fibres and optic radiations. The variable phenotypes in the remaining cases lacking LMNB1 defects (five with autosomal dominant transmission) suggest that adult-onset leucoencephalopathies are genetically heterogeneous.
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Affiliation(s)
- A Brussino
- Department of Genetics, Biology and Biochemistry, University of Torino, via Santena, 19-10126 Torino, Italy.
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Cagnoli C, Brussino A, Sbaiz L, Di Gregorio E, Atzori C, Caroppo P, Orsi L, Migone N, Buffa C, Imperiale D, Brusco A. A previously undiagnosed case of Gerstmann-Sträussler-Scheinker disease revealed by PRNP gene analysis in patients with adult-onset ataxia. Mov Disord 2008; 23:1468-71. [PMID: 18566986 DOI: 10.1002/mds.21953] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Ataxia is a frequently reported symptom in prion diseases (PD) and it is characteristic of Gerstmann-Sträussler-Scheinker syndrome (GSS), a genetic PD mainly related to the P102L mutation in the PRNP gene. Our aim was to screen for the P102L and other six known PRNP gene mutations (P105L, A117V, Y145X, E200K, D202N, and V210I) a group of 206 consecutive patients diagnosed with adult-onset cerebellar ataxia of unknown origin. The patients, negative for the most common acquired and genetic forms, were analyzed using a combination of restriction endonuclease digestion and pyrosequencing; eight, affected by ataxia and cognitive dysfunction, were also sequenced for the PRNP gene. One patient resulted to be heterozygous for the P102L mutation. Retrospectively, the clinical picture was consistent with a "classical" GSS phenotype. In conclusion, the screening for the P102L mutation, or even the sequencing of the PRNP gene should be taken in consideration in patients with late-onset ataxia (>50 years).
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Affiliation(s)
- Claudia Cagnoli
- Department of Genetics, Biology and Biochemistry, University of Torino, Medical Genetics Unit, Az. Osp. San Giovanni Battista, Torino, Italy
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Cagnoli C, Brussino A, Di Gregorio E, Caroppo P, Stola S, Dragone E, Ferrone M, Padovan S, Migone N, Orsi L, Brusco A. Mutations in the POLG1 gene are not a relevant cause of cerebellar ataxia in Italy. J Neurol 2008; 255:1079-80. [PMID: 18446310 DOI: 10.1007/s00415-008-0772-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2006] [Revised: 10/02/2007] [Accepted: 10/09/2007] [Indexed: 11/25/2022]
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Cagnoli C, Brussino A, Di Gregorio E, Brusco A, Stevanin G, Durr A, Brice A. The (−16C > T) substitution in thePLEKHG4 gene is not present among European ADCA patients. Mov Disord 2007; 22:752-3. [PMID: 17290458 DOI: 10.1002/mds.21389] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Cagnoli C, Stevanin G, Michielotto C, Gerbino Promis G, Brussino A, Pappi P, Durr A, Dragone E, Viemont M, Gellera C, Brice A, Migone N, Brusco A. Large pathogenic expansions in the SCA2 and SCA7 genes can be detected by fluorescent repeat-primed polymerase chain reaction assay. J Mol Diagn 2006; 8:128-32. [PMID: 16436644 PMCID: PMC1867568 DOI: 10.2353/jmoldx.2006.050043] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Large expansions in the SCA2 and SCA7 genes (>100 CAG repeats) have been associated with juvenile and infantile forms of cerebellar ataxias that cannot be detected using standard polymerase chain reaction (PCR). Here, we describe a successful application of the fluorescent short tandem repeat-primed PCR method for accurate identification of these expanded repeats. The test is robust, reliable, and inexpensive and can be used to screen large series of patients, although it cannot give a precise evaluation of the size of the expansion. This test may be of practical value in prenatal diagnoses offered to affected or pre-symptomatic at-risk parents, in which a very large expansion inherited from one of the parents can be missed in the fetus by standard PCR.
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Affiliation(s)
- Claudia Cagnoli
- Dipartimento di Genetica Biologia e Biochimica, Università degli Studi di Torino, via Santena 19, 10126, Torino, Italy
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Saluto A, Brussino A, Tassone F, Arduino C, Cagnoli C, Pappi P, Hagerman P, Migone N, Brusco A. An enhanced polymerase chain reaction assay to detect pre- and full mutation alleles of the fragile X mental retardation 1 gene. J Mol Diagn 2006; 7:605-12. [PMID: 16258159 PMCID: PMC1867559 DOI: 10.1016/s1525-1578(10)60594-6] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
Several diagnostic strategies have been applied to the detection of FMR1 gene repeat expansions in fragile X syndrome. Here, we report a novel polymerase chain reaction-based strategy using the Expand Long Template PCR System (Roche Diagnostics, Mannheim, Germany) and the osmolyte betaine. Repeat expansions up to approximately 330 CGGs in males and up to at least approximately 160 CGGs in carrier women could be easily visualized on ethidium bromide agarose gels. We also demonstrated that fluorescence analysis of polymerase chain reaction products was a reliable tool to verify the presence of premutation and full mutation alleles both in males and in females. This technique, primarily designed to detect premutation alleles, can be used as a routine first screen for expanded FMR1 alleles.
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Affiliation(s)
- Alessandro Saluto
- Dipartimento di Genetica Biologia e Biochimica, Università degli Studi di Torino, via Santena 19, 10126 Torino, Italy
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Cagnoli C, Mariotti C, Taroni F, Seri M, Brussino A, Michielotto C, Grisoli M, Di Bella D, Migone N, Gellera C, Di Donato S, Brusco A. SCA28, a novel form of autosomal dominant cerebellar ataxia on chromosome 18p11.22-q11.2. ACTA ACUST UNITED AC 2005; 129:235-42. [PMID: 16251216 DOI: 10.1093/brain/awh651] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We describe a four-generation Italian family with a novel form of juvenile-onset, slowly progressive, autosomal dominant cerebellar ataxia. Eleven affected family members have been evaluated. The mean age at onset was 19.5 years with no evidence of anticipation. The first symptoms were invariably unbalanced standing and mild gait incoordination. Gaze-evoked nystagmus was prominent at onset, while patients with longer disease duration developed slow saccades, ophthalmoparesis and, often, ptosis. Deep tendon reflexes in lower limbs were increased in 80% of the cases. Genetic analysis excluded the presence of pathological repeat expansions in spinocerebellar ataxia (SCA) types 1-3, 6-8, 10, 12 and 17, and DRPLA genes. Linkage exclusion tests showed no evidence of association with other known SCA loci. A genome-wide screen analysis identified linkage with chromosome 18 markers. A maximum two-point limit of determination score of 4.20 was found for marker D18S53. Haplotype analysis refined a critical region of 7.9 Mb between markers D18S1418 and D18S1104. This new SCA locus on 18p11.22-q11.2 has been designated SCA28. Candidate genes within the critical interval are currently screened for mutations.
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Affiliation(s)
- Claudia Cagnoli
- Dipartimento di Genetica Biologia e Biochimica, Università degli Studi di Torino and S.C. Genetica Medica, Ospedale San Giovanni Battista di Torino, Torino, Italy
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Brussino A, Gellera C, Saluto A, Mariotti C, Arduino C, Castellotti B, Camerlingo M, de Angelis V, Orsi L, Tosca P, Migone N, Taroni F, Brusco A. FMR1 gene premutation is a frequent genetic cause of late-onset sporadic cerebellar ataxia. Neurology 2005; 64:145-7. [PMID: 15642922 DOI: 10.1212/01.wnl.0000148723.37489.3f] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
In an Italian population of 275 unrelated men affected by adult-onset sporadic progressive cerebellar ataxia, the authors found six patients carrying an FMR1 gene premutation. Age at onset (range, 53 to 69 years) and clinical-neuropathologic findings were consistent with the fragile-X tremor ataxia syndrome (FXTAS), although tremor was not as common as previously described. FXTAS accounted for 4.2% of the cases diagnosed at >50 years, suggesting that it is a frequent genetic cause of late-onset sporadic ataxia.
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Affiliation(s)
- A Brussino
- Dipartimento di Genetica, Biologia e Biochimica, Università degli Studi di Torinoand S.C. Genetica Medica, Ospedale San Giovanni Battista di Torino, Turin, Italy.
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