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Schipper LJ, Raaphorst J, Aronica E, Baas F, de Haan R, de Visser M, Troost D. Prevalence of brain and spinal cord inclusions, including dipeptide repeat proteins, in patients with the C9ORF72 hexanucleotide repeat expansion: a systematic neuropathological review. Neuropathol Appl Neurobiol 2016; 42:547-60. [DOI: 10.1111/nan.12284] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 08/27/2015] [Indexed: 12/12/2022]
Affiliation(s)
- L. J. Schipper
- Department of Neurology; Academic Medical Center; University of Amsterdam; Amsterdam The Netherlands
| | - J. Raaphorst
- Department of Neurology; Academic Medical Center; University of Amsterdam; Amsterdam The Netherlands
- Department of Neurology; Radboud University Medical Center; Nijmegen The Netherlands
| | - E. Aronica
- Department of Neuropathology; Academic Medical Center; University of Amsterdam; Amsterdam The Netherlands
| | - F. Baas
- Department of Genome Analysis; Academic Medical Center; University of Amsterdam; Amsterdam The Netherlands
| | - R. de Haan
- Clinical Research Unit; Academic Medical Center; University of Amsterdam; Amsterdam The Netherlands
| | - M. de Visser
- Department of Neurology; Academic Medical Center; University of Amsterdam; Amsterdam The Netherlands
| | - D. Troost
- Department of Neuropathology; Academic Medical Center; University of Amsterdam; Amsterdam The Netherlands
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Benussi A, Padovani A, Borroni B. Phenotypic Heterogeneity of Monogenic Frontotemporal Dementia. Front Aging Neurosci 2015; 7:171. [PMID: 26388768 PMCID: PMC4555036 DOI: 10.3389/fnagi.2015.00171] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 08/19/2015] [Indexed: 12/12/2022] Open
Abstract
Frontotemporal dementia (FTD) is a genetically and pathologically heterogeneous disorder characterized by personality changes, language impairment, and deficits of executive functions associated with frontal and temporal lobe degeneration. Different phenotypes have been defined on the basis of presenting clinical symptoms, i.e., the behavioral variant of FTD, the agrammatic variant of primary progressive aphasia, and the semantic variant of PPA. Some patients have an associated movement disorder, either parkinsonism, as in progressive supranuclear palsy and corticobasal syndrome, or motor neuron disease (FTD-MND). A family history of dementia is found in 40% of cases of FTD and about 10% have a clear autosomal-dominant inheritance. Genetic studies have identified several genes associated with monogenic FTD: microtubule-associated protein tau, progranulin, TAR DNA-binding protein 43, valosin-containing protein, charged multivesicular body protein 2B, fused in sarcoma, and the hexanucleotide repeat expansion in intron 1 of the chromosome 9 open reading frame 72. Patients often present with an extensive phenotypic variability, even among different members of the same kindred carrying an identical disease mutation. The objective of the present work is to review and evaluate available literature data in order to highlight recent advances in clinical, biological, and neuroimaging features of monogenic frontotemporal lobar degeneration and try to identify different mechanisms underlying the extreme phenotypic heterogeneity that characterizes this disease.
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Affiliation(s)
- Alberto Benussi
- Centre for Ageing Brain and Neurodegenerative Disorders, Neurology Unit, Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy
| | - Alessandro Padovani
- Centre for Ageing Brain and Neurodegenerative Disorders, Neurology Unit, Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy
| | - Barbara Borroni
- Centre for Ageing Brain and Neurodegenerative Disorders, Neurology Unit, Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy
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Xiao S, MacNair L, McGoldrick P, McKeever PM, McLean JR, Zhang M, Keith J, Zinman L, Rogaeva E, Robertson J. Isoform-specific antibodies reveal distinct subcellular localizations of C9orf72 in amyotrophic lateral sclerosis. Ann Neurol 2015; 78:568-83. [PMID: 26174152 DOI: 10.1002/ana.24469] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 06/30/2015] [Accepted: 06/30/2015] [Indexed: 12/26/2022]
Abstract
OBJECTIVE A noncoding hexanucleotide repeat expansion in C9orf72 is the most common cause of amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). It has been reported that the repeat expansion causes a downregulation of C9orf72 transcripts, suggesting that haploinsufficiency may contribute to disease pathogenesis. Two protein isoforms are generated from three alternatively spliced transcripts of C9orf72; a long form (C9-L) and a short form (C9-S), and their function(s) are largely unknown owing to lack of specific antibodies. METHODS To investigate C9orf72 protein properties, we developed novel antibodies that recognize either C9-L or C9-S. Multiple techniques, including Western blot, immunohistochemistry, and coimmunoprecipitation, were used to determine the expression levels and subcellular localizations of C9-L and C9-S. RESULTS Investigation of expression of C9-L and C9-S demonstrated distinct biochemical profiles, region-specific changes, and distinct subcellular localizations in ALS tissues. In particular, C9-L antibody exhibited a diffuse cytoplasmic staining in neurons and labeled large speckles in cerebellar Purkinje cells. In contrast, C9-S antibody gave very specific labeling of the nuclear membrane in healthy neurons, with apparent relocalization to the plasma membrane of diseased motor neurons in ALS. Coimmunoprecipitation experiments revealed an interaction of the C9-isoforms with both Importin β1 and Ran-GTPase, components of the nuclear pore complex. INTERPRETATION Using these antibodies, we have shown that C9orf72 may be involved in nucleocytoplasmic shuttling and this may have relevance to pathophysiology of ALS/FTLD. Our antibodies have provided improved detection of C9orf72 protein isoforms, which will help elucidate its physiological function and role in ALS/FTLD.
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Affiliation(s)
- Shangxi Xiao
- Tanz Center for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada
| | - Laura MacNair
- Tanz Center for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Philip McGoldrick
- Tanz Center for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada
| | - Paul M McKeever
- Tanz Center for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Jesse R McLean
- Tanz Center for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada
| | - Ming Zhang
- Tanz Center for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada
| | - Julia Keith
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.,Sunnybrook Health Sciences Center, Toronto, Ontario, Canada
| | - Lorne Zinman
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.,Sunnybrook Health Sciences Center, Toronto, Ontario, Canada
| | - Ekaterina Rogaeva
- Tanz Center for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada
| | - Janice Robertson
- Tanz Center for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada
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Xi Z, Zinman L, Moreno D, Schymick J, Liang Y, Sato C, Zheng Y, Ghani M, Dib S, Keith J, Robertson J, Rogaeva E. Hypermethylation of the CpG island near the G4C2 repeat in ALS with a C9orf72 expansion. Am J Hum Genet 2013; 92:981-9. [PMID: 23731538 DOI: 10.1016/j.ajhg.2013.04.017] [Citation(s) in RCA: 207] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 04/05/2013] [Accepted: 04/22/2013] [Indexed: 12/13/2022] Open
Abstract
The G4C2 repeat expansion in C9orf72 is the most common known cause of amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). We tested the hypothesis that the repeat expansion causes aberrant CpG methylation near the G4C2 repeat, which could be responsible for the downregulation of gene expression. We investigated the CpG methylation profile by two methods using genomic DNA from the blood of individuals with ALS (37 expansion carriers and 64 noncarriers), normal controls (n = 76), and family members of 7 ALS probands with the expansion. We report that hypermethylation of the CpG island 5' of the G4C2 repeat is associated with the presence of the expansion (p < 0.0001). A higher degree of methylation was significantly correlated with a shorter disease duration (p < 0.01), associated with familial ALS (p = 0.009) and segregated with the expansion in 7 investigated families. Notably, we did not detect methylation for either normal or intermediate alleles (up to 43 repeats), bringing to question the current cutoff of 30 repeats for pathological alleles. Our study raises several important questions for the future investigation of large data sets, such as whether the degree of methylation corresponds to clinical presentation (ALS versus FTLD).
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Affiliation(s)
- Zhengrui Xi
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, 6 Queen's Park Crescent West, Toronto, ON M5S 3H2, Canada
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