Publications by authors named "Ekaterina Rogaeva"

189 Publications

Association of apolipoprotein E variation with cognitive impairment across multiple neurodegenerative diagnoses.

Neurobiol Aging 2021 Apr 24. Epub 2021 Apr 24.

Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada.

For many years there has been uncertainty regarding how apolipoprotein E (APOE) E2 and E4 variants may influence overlapping features of neurodegeneration, such as cognitive impairment. We aimed to identify whether the APOE variants are associated with cognitive function across various neurodegenerative and cerebrovascular diagnoses (n = 513). Utilizing a comprehensive neuropsychology battery, multivariate multiple regression was used to assess the influence of APOE carrier status and disease cohort on performance across five cognitive domains. Irrespective of disease cohort, E4 carriers had significantly lower performance in verbal memory and visuospatial domains than those with E3/3, while E2 carriers' cognitive performance was not significantly different. However, E2 carriers with frontotemporal dementia (FTD) performed significantly worse than those with E3/3 in the attention/working memory, executive function, and visuospatial domains. Our results highlight that the influence of APOE variation on cognition is complex, in some cases varying based on diagnosis and possibly underlying disease pathology.
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http://dx.doi.org/10.1016/j.neurobiolaging.2021.04.011DOI Listing
April 2021

Occurrence of Amyotrophic Lateral Sclerosis in Type 1 Gaucher Disease.

Neurol Genet 2021 Aug 18;7(4):e600. Epub 2021 May 18.

Krembil Research Institute (L.M.O., L.V.K.), Toronto Western Hospital, University Health Network, Ontario; Djavad Mowafaghian Centre for Brain Health (T.R.), Division of Neurology, Department of Medicine, University of British Columbia, Vancouver; Mark Feedman and Judy Jacobs Program for Gaucher Disease (G.A.M.N., D. Amato, L.V.K.), Mount Sinai Hospital; Fred A. Litwin Family Centre for Genetic Medicine (G.A.M.N., D.-L.N.), Department of Medicine, Mount Sinai Hospital and Toronto General Hospital, University Health Network, University of Toronto, Ontario; Department of Human Genetics (J.P.R., P.A.D., G.A.R., Z.G.-O.), Montreal Neurological Institute and Hospital (J.P.R., P.A.D., G.A.R., Z.G.-O.), and Department of Neurology and Neurosurgery (P.A.D., G.A.R., Z.G.-O.), McGill University, Quebec; Tanz Centre for Research in Neurodegenerative Diseases (M.Z., E.A.R., L.V.K.), University of Toronto, Ontario, Canada; Shanghai First Rehabilitation Hospital (M.Z.), School of Medicine, Clinical Center for Brain and Spinal Cord Research (M.Z.), and Institute for Advanced Study (M.Z.), Tongji University, Shanghai, China; Department of Neurology (D. Arkadir, M.G.), Hadassah Medical Center, Hebrew University, Jerusalem, Israel; Ellen and Martin Prosserman Centre for Neuromuscular Diseases (C.B.), Division of Neurology, Department of Medicine, Toronto General Hospital, University Health Network, University of Toronto; London Health Sciences Centre (C.L.S.), London, Ontario, Canada; Gaucher Unit (A.Z.), Shaare Zedek Medical Center, Hadassah Medical School, Hebrew University, Jerusalem, Israel; Division of Neurology (L.Z.), Department of Medicine, Sunnybrook Health Sciences Centre, University of Toronto; and Edmond J. Safra Program in Parkinson's Disease and the Morton and Gloria Shulman Movement Disorders Clinic (L.V.K.), Division of Neurology, Department of Medicine, Toronto Western Hospital, University Health Network, University of Toronto, Ontario, Canada.

Objective: To report the association between type 1 Gaucher disease (GD1) and amyotrophic lateral sclerosis (ALS) in 3 unrelated families and to explore whether variants influence the risk of ALS.

Methods: We conducted retrospective chart reviews of patients with GD1 or their family members diagnosed with ALS. To further investigate whether there is an association between ALS and GD, we performed exploratory analyses for the presence of variants in 3 ALS cohorts from Toronto (Canada), Montreal (Canada), and Project MinE (international), totaling 4,653 patients with ALS and 1,832 controls.

Results: We describe 2 patients with GD1 and 1 obligate mutation carrier (mother of GD1 patient) with ALS. We identified 0 and 8 carriers in the Toronto and Montreal cohorts, respectively. The frequencies of variants in patients with ALS in the Montreal and Project MinE cohorts were similar to those of Project MinE controls or Genome Aggregation Database population controls.

Conclusions: The occurrence of ALS in biallelic or monoallelic mutation carriers described here, in addition to common pathogenic pathways shared by GD1 and ALS, suggests that variants could influence ALS risk. However, analyses of variants in ALS cohorts did not reveal a meaningful association. Examination of larger cohorts and neuropathologic studies will be required to elucidate whether patients with GD1 are indeed at increased risk for ALS.
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http://dx.doi.org/10.1212/NXG.0000000000000600DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8130998PMC
August 2021

Genomewide Association Studies of LRRK2 Modifiers of Parkinson's Disease.

Ann Neurol 2021 Jul 17;90(1):76-88. Epub 2021 May 17.

23andMe, Inc., Sunnyvale, CA.

Objective: The aim of this study was to search for genes/variants that modify the effect of LRRK2 mutations in terms of penetrance and age-at-onset of Parkinson's disease.

Methods: We performed the first genomewide association study of penetrance and age-at-onset of Parkinson's disease in LRRK2 mutation carriers (776 cases and 1,103 non-cases at their last evaluation). Cox proportional hazard models and linear mixed models were used to identify modifiers of penetrance and age-at-onset of LRRK2 mutations, respectively. We also investigated whether a polygenic risk score derived from a published genomewide association study of Parkinson's disease was able to explain variability in penetrance and age-at-onset in LRRK2 mutation carriers.

Results: A variant located in the intronic region of CORO1C on chromosome 12 (rs77395454; p value = 2.5E-08, beta = 1.27, SE = 0.23, risk allele: C) met genomewide significance for the penetrance model. Co-immunoprecipitation analyses of LRRK2 and CORO1C supported an interaction between these 2 proteins. A region on chromosome 3, within a previously reported linkage peak for Parkinson's disease susceptibility, showed suggestive associations in both models (penetrance top variant: p value = 1.1E-07; age-at-onset top variant: p value = 9.3E-07). A polygenic risk score derived from publicly available Parkinson's disease summary statistics was a significant predictor of penetrance, but not of age-at-onset.

Interpretation: This study suggests that variants within or near CORO1C may modify the penetrance of LRRK2 mutations. In addition, common Parkinson's disease associated variants collectively increase the penetrance of LRRK2 mutations. ANN NEUROL 2021;90:82-94.
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http://dx.doi.org/10.1002/ana.26094DOI Listing
July 2021

Combined epigenetic/genetic study identified an ALS age of onset modifier.

Acta Neuropathol Commun 2021 04 23;9(1):75. Epub 2021 Apr 23.

Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, 60 Leonard Ave., Toronto, ON, M5T 0S8, Canada.

Age at onset of amyotrophic lateral sclerosis (ALS) is highly variable (eg, 27-74 years in carriers of the GC-expansion in C9orf72). It might be influenced by environmental and genetic factors via the modulation of DNA methylation (DNAm) at CpG-sites. Hence, we combined an epigenetic and genetic approach to test the hypothesis that some common single nucleotide polymorphisms (SNPs) at CpG-sites (CpG-SNPs) could modify ALS age of onset. Our genome-wide DNAm analysis suggested three CpG-SNPs whose DNAm levels are significantly associated with age of onset in 249 ALS patients (q < 0.05). Next, genetic analysis validated the association of rs4970944 with age of onset in the discovery (n = 469; P = 0.025) and replication (n = 4160; P = 0.007) ALS cohorts. A meta-analysis of the cohorts combined showed that the median onset in AA-carriers is two years later than in GG-carriers (n = 4629; P = 0.0012). A similar association was observed with its tagging SNPs, implicating a 16 Kb region at the 1q21.3 locus as a modifier of ALS age of onset. Notably, rs4970944 genotypes are also associated with age of onset in C9orf72-carriers (n = 333; P = 0.025), suggesting that each A-allele delays onset by 1.6 years. Analysis of Genotype-Tissue Expression data revealed that the protective A-allele is linked with the reduced expression of CTSS in cerebellum (P = 0.00018), which is a critical brain region in the distributed neural circuits subserving motor control. CTSS encodes cathepsin S protein playing a key role in antigen presentation. In conclusion, we identified a 16 Kb locus tagged by rs4970944 as a modifier of ALS age of onset. Our findings support the role of antigen presenting processes in modulating age of onset of ALS and suggest potential drug targets (eg, CTSS). Future replication studies are encouraged to validate the link between the locus tagged by rs4970944 and age of onset in independent ALS cohorts, including different ethnic groups.
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http://dx.doi.org/10.1186/s40478-021-01183-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8066440PMC
April 2021

Genome sequencing analysis identifies new loci associated with Lewy body dementia and provides insights into its genetic architecture.

Nat Genet 2021 03 15;53(3):294-303. Epub 2021 Feb 15.

Reta Lila Weston Institute, UCL Queen Square Institute of Neurology, University College London, London, UK.

The genetic basis of Lewy body dementia (LBD) is not well understood. Here, we performed whole-genome sequencing in large cohorts of LBD cases and neurologically healthy controls to study the genetic architecture of this understudied form of dementia, and to generate a resource for the scientific community. Genome-wide association analysis identified five independent risk loci, whereas genome-wide gene-aggregation tests implicated mutations in the gene GBA. Genetic risk scores demonstrate that LBD shares risk profiles and pathways with Alzheimer's disease and Parkinson's disease, providing a deeper molecular understanding of the complex genetic architecture of this age-related neurodegenerative condition.
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http://dx.doi.org/10.1038/s41588-021-00785-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7946812PMC
March 2021

Early-Onset Alzheimer's Disease: What Is Missing in Research?

Curr Neurol Neurosci Rep 2021 01 19;21(2). Epub 2021 Jan 19.

The Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, USA.

Purpose Of Review: Early-onset Alzheimer's disease (EOAD), defined as Alzheimer's disease (AD) occurring before age 65, is significantly less well studied than the late-onset form (LOAD) despite EOAD often presenting with a more aggressive disease progression. The aim of this review is to summarize the current understanding of the etiology of EOAD, their translation into clinical practice, and to suggest steps to be taken to move our understanding forward.

Recent Findings: EOAD cases make up 5-10% of AD cases but only 10-15% of these cases show known mutations in the APP, PSEN1, and PSEN2, which are linked to EOAD. New data suggests that these unexplained cases following a non-Mendelian pattern of inheritance is potentially caused by a mix of common and newly discovered rare variants. However, only a fraction of this genetic variation has been identified to date leaving the molecular mechanisms underlying this type of AD and their association with clinical, biomarker, and neuropathological changes unclear. While great advancements have been made in characterizing EOAD, much work is needed to disentangle the molecular mechanisms underlying this type of AD and to identify putative targets for more precise disease screening, diagnosis, prevention, and treatment.
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http://dx.doi.org/10.1007/s11910-020-01090-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7815616PMC
January 2021

The Intersection between COVID-19, the Gene Family of ACE2 and Alzheimer's Disease.

Neurosci Insights 2020 22;15:2633105520975743. Epub 2020 Nov 22.

Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada.

We reviewed factors that might influence COVID-19 outcomes (eg, neurological symptoms), including the link to Alzheimer's disease. Since the virus triggers COVID-19 infection through binding to ACE2, we focused on the gene family, including . Both ACE2 and ACE are involved in the renin-angiotensin system (RAS). In general, ACE causes inflammation and vasoconstriction, while ACE2 leads to anti-inflammation activity and vasodilation. The disturbed balance between these counter-regulatory pathways could influence susceptibility to COVID-19. Notably, dysregulation of the RAS-equilibrium contributes to Alzheimer's disease. Differences in the incidence and symptoms of COVID-19 in diverse populations could be attributed to variability in the human genome. For example, and variations could modify the outcome of COVID-19 in different populations. It would be important to conduct genome-wide studies to detect variants influencing COVID-19 presentation, with a special focus on variants affecting immune-related pathways and expression of RAS-related genes.
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http://dx.doi.org/10.1177/2633105520975743DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7686598PMC
November 2020

Late-onset vs nonmendelian early-onset Alzheimer disease: A distinction without a difference?

Neurol Genet 2020 Oct 6;6(5):e512. Epub 2020 Oct 6.

Taub Institute for Research on Alzheimer's Disease and the Aging Brain (C.R.), Gertrude H. Sergievsky Center (C.R.), Department of Neurology (C.R.), and Department of Epidemiology (C.R.), College of Physicians and Surgeons, Columbia University, New York, NY; Tanz Centre for Research in Neurodegenerative Disease (E.R.), University of Toronto, ON, Canada; and The John P. Hussman Institute for Human Genomics (G.W.B.), University of Miami, FL.

There is mounting evidence that only a small fraction of early-onset Alzheimer disease cases (onset <65 years) are explained by known mutations. Even multiplex families with early onset often also have late-onset cases, suggesting that the commonly applied categorization of Alzheimer disease into early- and late-onset forms may not reflect distinct underlying etiology. Nevertheless, this categorization continues to govern today's research and the design of clinical trials. The aim of this review is to evaluate this categorization by providing a comprehensive, critical review of reported clinical, neuropathologic, and genomic characteristics of both onset-based subtypes and explore potential overlap between both categories. The article will lay out the need to comprehensively assess the phenotypic, neuropathologic, and molecular variability in Alzheimer disease and identify factors explaining the observed significant variation in onset age in persons with and without known mutations. The article will critically review ongoing large-scale genomic efforts in Alzheimer disease research (e.g., Alzheimer Disease Sequencing Project, Dominantly Inherited Alzheimer Network, Alzheimer Disease Neuroimaging Initiative) and their shortcomings to disentangle the delineation of unexplained nonmendelian early-onset from late-onset and mendelian forms of Alzheimer disease. In addition, it will outline specific approaches including epigenetic research through which a comprehensive characterization of this delineation can be achieved.
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http://dx.doi.org/10.1212/NXG.0000000000000512DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7673282PMC
October 2020

, age at onset, and ancestry help discriminate behavioral from language variants in FTLD cohorts.

Neurology 2020 12 17;95(24):e3288-e3302. Epub 2020 Sep 17.

From the Institute of Neurology (B.C., D.A.K., J.H., P.A.L., R.F.), School of Pharmacy (C.M.), and UCL Movement Disorders Centre (J.H.), University College London; School of Pharmacy (C.M., P.A.L.), University of Reading, Whiteknights; Neurogenetics Laboratory (M.B.-Q., C.W., J.M.P.), National Hospital for Neurology and Neurosurgery, London, UK; Aptima Clinic (Miquel Aguilar), Terrassa; Memory Disorders Unit, Department of Neurology (I.A., M.D.-F., P.P.), University Hospital Mutua de Terrassa, Barcelona; Hospital Universitario Central de Asturias (V.A., M.M.-G.), Oviedo, Spain; NORMENT (O.A.), Institute of Clinical Medicine, University of Oslo, Norway; Regional Neurogenetic Centre (Maria Anfossi, Livia Bernardi, A.C.B., M.E.C., Chiara Cupidi, F.F., Maura Gallo, R.M., N.S.), ASPCZ, Lamezia Terme; Department of Neuroscience, Psychology, Drug Research and Child Health (S.B., B.N., I.P., S.S.), University of Florence; Molecular Markers Laboratory (Luisa Benussi, Giuliano Binetti, R.G.), IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy; Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience (D.B.), University of Sheffield, UK; Research Center and Memory Clinic (M.B., I.H., S.M.-G., Agustín Ruiz), Fundació ACE, Institut Català de Neurociències Aplicades, Universitat Internacional de Catalunya (UIC), Barcelona, Spain; Centre for Neurodegenerative Disorders (B.B., A.P.), Department of Clinical and Experimental Sciences, University of Brescia, Italy; Department of Clinical Neurosciences (Lucy Bowns, T.E.C., J.B.R.), Cambridge University, UK; Department of Neurology (Geir Bråthen, S.B.S.), University Hospital of Trondheim, Norway; Dept NVS, Division of Neurogeriatrics (H.-H.C., C.G., B.K., L.Ö.), Karolinska Institutet, Bioclinicum Solna, Sweden; Department of Neurology (J.C., O.D.-I., I.I.-G., A.L.), IIB Sant Pau, Hospital de la Santa Creu i Sant Pau, Universitat Autònoma de Barcelona, Spain; Anne Rowling Regenerative Neurology Clinic (S.C., G.J.T.H., S.P.) and Centre for Clinical Brain Sciences (S.P.), University of Edinburgh, UK; NeuroGenomics and Informatics, Department of Psychiatry (Carlos Cruchaga), Washington University, St. Louis, MO; Cognitive Impairment Center (M.E.D.B., Maurizio Gallucci) and Immunohematology and Transfusional Medicine Service (E.D., A.V.), Local Health Authority n.2 Marca Trevigiana, Treviso, Italy; Department of Psychiatry and Psychotherapy (J.D.-S., C.R.), School of Medicine, Technical University of Munich, Germany; Department of Neurology (D.F., M.G.K.) and Clinical Institute of Medical Genetics (A.M., B.P.), University Medical Center Ljubljana, Slovenia; Dino Ferrari Center (D.G., Elio Scarpini, M.S.), University of Milan, Italy; Cognitive Neuroscience Lab, Think and Speak Lab (J.H.G.), Shirley Ryan Ability Lab, Chicago, IL; Department of Pathology and Laboratory Medicine (Murray Grossman, EunRan Suh, J.Q.T., V.M.V.D.), Center for Neurodegenerative Diseases, Perelman School of Medicine at the University of Pennsylvania, Philadelphia; UCL Dementia Research Institute (J.H.), London; Reta Lila Weston Institute (J.H.), UCL Queen Square Institute of Neurology, UK; Institute for Advanced Study (J.H.), The Hong Kong University of Science and Technology, China; Royal Edinburgh Hospital (G.J.T.H.), UK; Taub Institute for Research on Alzheimer's Disease and the Aging Brain (E.D.H.), Columbia University, New York, NY; Department of Neurology, Memory and Aging Center (A.K., B.M., J.Y.), University of California, San Francisco; UCL Genomics (M.K., G.K.M., Y.P.), UCL Great Ormond Street Institute of Child Health, London, UK; Geriatric Center Frullone ASL Napoli 1 Centro (G.M.), Napoli, Italy; Department of Neurology (M.O.M., J.v.R., J.C.V.S.), Erasmus Medical Center, Rotterdam, the Netherlands; Rona Holdings (P.M.), Silicon Valley, CA; Newcastle Brain Tissue Resource, Institute of Neuroscience (C.M.M.), Newcastle University, Campus for Ageing and Vitality, Newcastle upon Tyne, UK; Department of Neurology (C.N.), Skåne University Hospital, Malmö, Sweden; Fondazione Policlinico Universitario A. Gemelli IRCCS (V.N.), Rome, Italy; Division of Neuroscience & Experimental Psychology (S.P.-B., A.M.T.R., S.R., J.C.T.), University of Manchester, UK; Amsterdam University Medical Center (Y.A.L.P.), VU University Medical Center, the Netherlands; Cardiovascular Research Unit (A.A.P.), IRCCS Multimedica, Milan; Neurology I, Department of Neuroscience (I.R., Elisa Rubino), University of Torino; NeurOMICS laboratory (G.M., Antonella Rendina, E.V.), Institute of Biochemistry and Cell Biology (IBBC), CNR Napoli, Italy; Manchester Centre for Clinical Neurosciences (A.M.T.R., J.S., J.C.T.), Salford Royal NHS Trust, Manchester, UK; Tanz Centre for Research in Neurodegenerative Diseases (Ekaterina Rogaeva), University of Toronto, Canada; Department of Biotechnology (B.R.), Jožef Stefan Institute, Ljubljana, Slovenia; Division of Neurology V and Neuropathology (G.R., F.T.), Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy; Alzheimer's Disease and Other Cognitive Disorders Unit (R.S.-V.), Hospital Clínic of Barcelona, Spain; Clinical Memory Research Unit, Department of Clinical Sciences Malmö (C.N., A.F.S.), and Division of Clinical Sciences Helsingborg, Department of Clinical Sciences Lund (M.L.W.), Lund University, Sweden; Neurodegenerative Brain Diseases Group (J.V.d.Z., C.V.B.), Center for Molecular Neurology, VIB, Antwerp, Belgium; Medical Research Council Centre for Neuropsychiatric Genetics and Genomics (V.E.-P.), Division of Psychological Medicine and Clinical Neurosciences and Dementia Research Institute, Cardiff University, UK; Instituto de Investigación Sanitaria del Principado de Asturias (V.A.), Oviedo, Asturias; Fundació per la Recerca Biomèdica i Social Mútua Terrassa (I.A., M.D.-F., P.P.), Barcelona; Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED) (M.B., J.C., O.D.-I., I.H., I.I.-G., A.L., S.M.-G., Agustín Ruiz), Instituto de Salud Carlos III, Madrid, Spain; MRC Cognition and Brain Sciences Unit (Lucy Bowns, T.E.C., J.B.R.), Cambridge University, UK; Department of Neuromedicine and Movement Science (Geir Bråthen, S.B.S.), Norwegian University of Science and Technology, Trondheim, Norway; Unit for Hereditary Dementias (H.-H.C., C.G., B.K., L.Ö.), Theme Aging, Karolinska University Hospital, Solna, Sweden; Medical Faculty (D.F., M.G.K.), University of Ljubljana, Slovenia; Fondazione IRCCS Ca'Granda (D.G., Elio Scarpini, M.S.), Ospedale Policlinico, Milan, Italy; Penn Center for Frontotemporal Degeneration (Murray Grossman), Philadelphia, PA; Universidad de Oviedo (M.M.-G.), Asturias, Spain; IRCCS Fondazione Don Carlo Gnocchi (B.N., S.S.), Florence; Istituto di Medicina Genomica (V.N.), Università Cattolica del sacro Cuore, Rome, Italy; Amsterdam Neuroscience (Y.A.L.P.), the Netherlands; Department of Medicine and Surgery (A.A.P.), University of Salerno, Baronissi (SA), Italy; Faculty of Chemistry and Chemical Technology (B.R.), University of Ljubljana, Slovenia; Institud d'Investigacions Biomèdiques August Pi i Sunyer (R.S.-V.), Barcelona, Spain; Department of Biomedical Sciences (J.V.d.Z., C.V.B.), University of Antwerp, Belgium; and Department of Comparative Biomedical Sciences (P.A.L.), The Royal Veterinary College, London, UK.

Objective: We sought to characterize expansions in relation to genetic ancestry and age at onset (AAO) and to use these measures to discriminate the behavioral from the language variant syndrome in a large pan-European cohort of frontotemporal lobar degeneration (FTLD) cases.

Methods: We evaluated expansions frequency in the entire cohort (n = 1,396; behavioral variant frontotemporal dementia [bvFTD] [n = 800], primary progressive aphasia [PPA] [n = 495], and FTLD-motor neuron disease [MND] [n = 101]). We then focused on the bvFTD and PPA cases and tested for association between expansion status, syndromes, genetic ancestry, and AAO applying statistical tests comprising Fisher exact tests, analysis of variance with Tukey post hoc tests, and logistic and nonlinear mixed-effects model regressions.

Results: We found pathogenic expansions in 4% of all cases (56/1,396). Expansion carriers differently distributed across syndromes: 12/101 FTLD-MND (11.9%), 40/800 bvFTD (5%), and 4/495 PPA (0.8%). While addressing population substructure through principal components analysis (PCA), we defined 2 patients groups with Central/Northern (n = 873) and Southern European (n = 523) ancestry. The proportion of expansion carriers was significantly higher in bvFTD compared to PPA (5% vs 0.8% [ = 2.17 × 10; odds ratio (OR) 6.4; confidence interval (CI) 2.31-24.99]), as well as in individuals with Central/Northern European compared to Southern European ancestry (4.4% vs 1.8% [ = 1.1 × 10; OR 2.5; CI 1.17-5.99]). Pathogenic expansions and Central/Northern European ancestry independently and inversely correlated with AAO. Our prediction model (based on expansions status, genetic ancestry, and AAO) predicted a diagnosis of bvFTD with 64% accuracy.

Conclusions: Our results indicate correlation between pathogenic expansions, AAO, PCA-based Central/Northern European ancestry, and a diagnosis of bvFTD, implying complex genetic risk architectures differently underpinning the behavioral and language variant syndromes.
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http://dx.doi.org/10.1212/WNL.0000000000010914DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7836664PMC
December 2020

DNA Methylation Clocks and Their Predictive Capacity for Aging Phenotypes and Healthspan.

Neurosci Insights 2020 21;15:2633105520942221. Epub 2020 Jul 21.

Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada.

The number of age predictors based on DNA methylation (DNAm) profile is rising due to their potential in predicting healthspan and application in age-related illnesses, such as neurodegenerative diseases. The cumulative assessment of DNAm levels at age-related CpGs (DNAm clock) may reflect biological aging. Such DNAm clocks have been developed using various training models and could mirror different aspects of disease/aging mechanisms. Hence, evaluating several DNAm clocks together may be the most effective strategy in capturing the complexity of the aging process. However, various confounders may influence the outcome of these age predictors, including genetic and environmental factors, as well as technical differences in the selected DNAm arrays. These factors should be taken into consideration when interpreting DNAm clock predictions. In the current review, we discuss 15 reported DNAm clocks with consideration for their utility in investigating neurodegenerative diseases and suggest research directions towards developing a more optimal measure for biological aging.
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http://dx.doi.org/10.1177/2633105520942221DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7376380PMC
July 2020

Parkinson's Disease, NOTCH3 Genetic Variants, and White Matter Hyperintensities.

Mov Disord 2020 11 23;35(11):2090-2095. Epub 2020 Jun 23.

Edmond J. Safra Program in Parkinson's Disease and the Morton and Gloria Shulman Movement Disorders Clinic, Toronto Western Hospital, Toronto, Ontario, Canada.

Background: White matter hyperintensities (WMH) on magnetic resonance imaging may influence clinical presentation in patients with Parkinson's disease (PD), although their significance and pathophysiological origins remain unresolved. Studies examining WMH have identified pathogenic variants in NOTCH3 as an underlying cause of inherited forms of cerebral small vessel disease.

Methods: We examined NOTCH3 variants, WMH volumes, and clinical correlates in 139 PD patients in the Ontario Neurodegenerative Disease Research Initiative cohort.

Results: We identified 13 PD patients (~9%) with rare (<1% of general population), nonsynonymous NOTCH3 variants. Bayesian linear modeling demonstrated a doubling of WMH between variant negative and positive patients (3.1 vs. 6.9 mL), with large effect sizes for periventricular WMH (d = 0.8) and lacunes (d = 1.2). Negative correlations were observed between WMH and global cognition (r = -0.2).

Conclusion: The NOTCH3 rare variants in PD may significantly contribute to increased WMH burden, which in turn may negatively influence cognition. © 2020 International Parkinson and Movement Disorder Society.
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http://dx.doi.org/10.1002/mds.28171DOI Listing
November 2020

DNA methylation age acceleration is associated with ALS age of onset and survival.

Acta Neuropathol 2020 05 7;139(5):943-946. Epub 2020 Mar 7.

Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, 60 Leonard Ave., Toronto, ON, M5T 2S8, Canada.

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http://dx.doi.org/10.1007/s00401-020-02131-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7181538PMC
May 2020

Interaction of APOE4 alleles and PET tau imaging in former contact sport athletes.

Neuroimage Clin 2020 13;26:102212. Epub 2020 Feb 13.

Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, 60 Leonard avenue, Toronto, ON M5T 0S8, Canada; Institute of Medical Science, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada; Division of Neurology, Toronto Western Hospital, University Health Network, 399 Bathurst St., Toronto, ON, M5T 2S8, Canada; Canadian Concussion Center, Toronto Western Hospital, Krembil Neuroscience Centre, University Health Network, 399 Bathurst St., Toronto, ON, M5T 2S8, Canada. Electronic address:

Background: Genetic polymorphisms like apolipoprotein E (APOE) and microtubule-associated protein tau (MAPT) genes increase the risk of neurodegeneration.

Methods: 38 former players (age 52.63±14.02) of contact sports underwent neuroimaging, biofluid collection, and comprehensive neuropsychological assessment. The [F-18]AV-1451 tracer signal was compared in the cortical grey matter between APOE4 allele carriers and non-carriers as well as carriers of MAPT H1H1 vs non-H1H1. Participants were then divided into the high (N = 13) and low (N = 13) groups based on cortical PET tau standard uptake value ratios (SUVRs) for comparison.

Findings: Cortical grey matter PET tau SUVR values were significantly higher in APOE4 carriers compared to non-carriers (p = 0.020). In contrast, there was no significant difference in SUVR between MAPT H1H1 vs non-H1H1 carrier genes (p = 1.00). There was a significantly higher APOE4 allele frequency in the high cortical grey matter PET tau group, comparing to low cortical grey matter PET tau group (p = 0.048). No significant difference in neuropsychological function was found between APOE4 allele carriers and non-carriers.

Interpretation: There is an association between higher cortical grey matter tau burden as seen with [F-18]AV-1451 PET tracer SUVR, and the APOE4 allele in former professional and semi-professional players at high risk of concussions. APOE4 allele may be a risk factor for tau accumulation in former contact sports athletes at high risk of neurodegeneration.

Funding: Toronto General and Western Hospital Foundations; Weston Brain Institute; Canadian Consortium on Neurodegeneration in ageing; Krembil Research Institute. There was no role of the funders in this study.
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http://dx.doi.org/10.1016/j.nicl.2020.102212DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7037542PMC
March 2021

Neuropathologic description of mutated amyotrophic lateral sclerosis.

Neurol Genet 2020 Feb 13;6(1):e394. Epub 2020 Jan 13.

Laboratory Medicine and Molecular Diagnostics (J.L.K., A.G., S.A.), Division of Anatomical Pathology, Sunnybrook Health Sciences Centre, University of Toronto; Department of Medicine (E.S., L.Z.), Division of Neurology, Sunnybrook Health Sciences Centre, University of Toronto, Ontario, Canada; School of Medicine and Institute for Advanced Study (M.Z.), Tongji University, Shanghai, China; and Tanz Centre for Research in Neurodegenerative Diseases (M.Z., P. McGoldrick, P. McKeever, J.R., E.R.), University of Toronto, Ontario, Canada.

Objective: To present the postmortem neuropathologic report of a patient with a mutation exhibiting an amyotrophic lateral sclerosis (ALS) clinical phenotype.

Methods: A 54-year-old man without significant medical history or family history presented with arm weakness, slowly progressed over 19 years to meet the El Escorial criteria for clinically probable ALS with bulbar and respiratory involvement, and was found to have a p.R15L mutation. Postmortem neuropathologic examination took place including immunohistochemical staining with CHCHD10, and double immunofluorescence combining CHCHD10 with TDP43 and neurofilament was performed and the results were compared with normal controls and sporadic ALS cases.

Results: Postmortem examination of the mutation carrier showed severe loss of hypoglossal and anterior horn motor neurons, mild corticospinal tract degeneration, and a relative lack of TDP43 immunopathology. CHCHD10 immunohistochemistry for the 3 controls and the 5 sporadic ALS cases showed strong neuronal cytoplasmic and axonal labeling, with the mutation carrier also having numerous CHCHD10 aggregates within their anterior horns. These aggregates may be related to the CHCHD10 aggregates recently described to cause mitochondrial degeneration and disease in a tissue-selective toxic gain-of-function fashion in a CHCHD10 knock-in mouse model. The CHCHD10 aggregates did not colocalize with TDP43 and were predominantly extracellular on double immunofluorescence labeling with neurofilament.

Conclusions: The neuropathology of CHCHD10 mutated ALS includes predominantly lower motor neuron degeneration, absent TDP43 immunopathology, and aggregates of predominantly extracellular CHCHD10, which do not contain TDP43.
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http://dx.doi.org/10.1212/NXG.0000000000000394DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6975173PMC
February 2020

Analysis of neurodegenerative disease-causing genes in dementia with Lewy bodies.

Acta Neuropathol Commun 2020 01 29;8(1). Epub 2020 Jan 29.

Neurology Service, University of Coimbra Hospital, Coimbra, Portugal.

Dementia with Lewy bodies (DLB) is a clinically heterogeneous disorder with a substantial burden on healthcare. Despite this, the genetic basis of the disorder is not well defined and its boundaries with other neurodegenerative diseases are unclear. Here, we performed whole exome sequencing of a cohort of 1118 Caucasian DLB patients, and focused on genes causative of monogenic neurodegenerative diseases. We analyzed variants in 60 genes implicated in DLB, Alzheimer's disease, Parkinson's disease, frontotemporal dementia, and atypical parkinsonian or dementia disorders, in order to determine their frequency in DLB. We focused on variants that have previously been reported as pathogenic, and also describe variants reported as pathogenic which remain of unknown clinical significance, as well as variants associated with strong risk. Rare missense variants of unknown significance were found in APP, CHCHD2, DCTN1, GRN, MAPT, NOTCH3, SQSTM1, TBK1 and TIA1. Additionally, we identified a pathogenic GRN p.Arg493* mutation, potentially adding to the diversity of phenotypes associated with this mutation. The rarity of previously reported pathogenic mutations in this cohort suggests that the genetic overlap of other neurodegenerative diseases with DLB is not substantial. Since it is now clear that genetics plays a role in DLB, these data suggest that other genetic loci play a role in this disease.
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http://dx.doi.org/10.1186/s40478-020-0879-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6990558PMC
January 2020

Genetic and epigenetic study of an Alzheimer's disease family with monozygotic triplets.

Brain 2019 11;142(11):3375-3381

Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, 60 Leonard Ave, Toronto, ON, Canada.

Age at onset of Alzheimer's disease is highly variable, and its modifiers (genetic or environmental) could act through epigenetic changes, such as DNA methylation at CpG sites. DNA methylation is also linked to ageing-the strongest Alzheimer's disease risk factor. DNA methylation age can be calculated using age-related CpGs and might reflect biological ageing. We conducted a clinical, genetic and epigenetic investigation of a unique Ashkenazi Jewish family with monozygotic triplets, two of whom developed Alzheimer's disease at ages 73 and 76, while the third at age 85 has no cognitive complaints or deficits in daily activities. One of their offspring developed Alzheimer's disease at age 50. Targeted sequencing of 80 genes associated with neurodegeneration revealed that the triplets and the affected offspring are heterozygous carriers of the risk APOE ε4 allele, as well as rare substitutions in APP (p.S198P), NOTCH3 (p.H1235L) and SORL1 (p.W1563C). In addition, we catalogued 52 possibly damaging rare variants detected by NeuroX array in affected individuals. Analysis of family members on a genome-wide DNA methylation chip revealed that the DNA methylation age of the triplets was 6-10 years younger than chronological age, while it was 9 years older in the offspring with early-onset Alzheimer's disease, suggesting accelerated ageing.
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http://dx.doi.org/10.1093/brain/awz289DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6821163PMC
November 2019

ε4, white matter hyperintensities, and cognition in Alzheimer and Lewy body dementia.

Neurology 2019 11 1;93(19):e1807-e1819. Epub 2019 Oct 1.

From the Division of Neurology, Department of Medicine (S.S.M., D.T.S., S.E.B., M.M.), Hurvitz Brain Sciences Research Program (S.S.M., J.R., D.T.S., D.Y., W.S., S.E.B., M.M.) and LC Campbell Cognitive Neurology Research Unit (U.S., J.R., S.M.N., D.Y., W.S., S.E.B., M.M.), Sunnybrook Research Institute, Institute of Medical Science (U.S., S.E.B., M.M.), Rehabilitation Sciences Institute (D.T.S., S.E.B.), and Department of Psychiatry (S.M.N.), Faculty of Medicine, Heart and Stroke Foundation Canadian Partnership for Stroke Recovery (J.R., D.Y., W.S., S.E.B.) and Department of Anatomic Pathology (J.K.), Sunnybrook Health Sciences Centre, Department of Psychology, Faculty of Arts and Science (D.T.S.), Department of Pharmacology & Toxicity (D.Y., W.S.), Tanz Centre for Research in Neurodegenerative Diseases (E.R., P.S.G.H.), and Institute of Biomaterials and Biomedical Engineering (S.E.B.), University of Toronto, Canada; Data Science Institute and Medical School (J.K.), Lancaster University, Lancaster; and Cambridge Institute for Medical Research (P.S.G.H.), Department of Clinical Neuroscience, University of Cambridge, UK.

Objective: To determine if ε4 influences the association between white matter hyperintensities (WMH) and cognitive impairment in Alzheimer disease (AD) and dementia with Lewy bodies (DLB).

Methods: A total of 289 patients (AD = 239; DLB = 50) underwent volumetric MRI, neuropsychological testing, and ε4 genotyping. Total WMH volumes were quantified. Neuropsychological test scores were included in a confirmatory factor analysis to identify cognitive domains encompassing attention/executive functions, learning/memory, and language, and factor scores for each domain were calculated per participant. After testing interactions between WMH and ε4 in the full sample, we tested associations of WMH with factor scores using linear regression models in ε4 carriers (n = 167) and noncarriers (n = 122). We hypothesized that greater WMH volume would relate to worse cognition more strongly in ε4 carriers. Findings were replicated in 198 patients with AD from the Alzheimer's Disease Neuroimaging Initiative (ADNI-I), and estimates from both samples were meta-analyzed.

Results: A significant interaction was observed between WMH and ε4 for language, but not for memory or executive functions. Separate analyses in ε4 carriers and noncarriers showed that greater WMH volume was associated with worse attention/executive functions, learning/memory, and language in ε4 carriers only. In ADNI-I, greater WMH burden was associated with worse attention/executive functions and language in ε4 carriers only. No significant associations were observed in noncarriers. Meta-analyses showed that greater WMH volume was associated with worse performance on all cognitive domains in ε4 carriers only.

Conclusion: ε4 may influence the association between WMH and cognitive performance in AD and DLB.
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http://dx.doi.org/10.1212/WNL.0000000000008377DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6946485PMC
November 2019

Genetic Variation in the Ontario Neurodegenerative Disease Research Initiative.

Can J Neurol Sci 2019 09 15;46(5):491-498. Epub 2019 Aug 15.

Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada.

Background/objective: Apolipoprotein E (APOE) E4 is the main genetic risk factor for Alzheimer's disease (AD). Due to the consistent association, there is interest as to whether E4 influences the risk of other neurodegenerative diseases. Further, there is a constant search for other genetic biomarkers contributing to these phenotypes, such as microtubule-associated protein tau (MAPT) haplotypes. Here, participants from the Ontario Neurodegenerative Disease Research Initiative were genotyped to investigate whether the APOE E4 allele or MAPT H1 haplotype are associated with five neurodegenerative diseases: (1) AD and mild cognitive impairment (MCI), (2) amyotrophic lateral sclerosis, (3) frontotemporal dementia (FTD), (4) Parkinson's disease, and (5) vascular cognitive impairment.

Methods: Genotypes were defined for their respective APOE allele and MAPT haplotype calls for each participant, and logistic regression analyses were performed to identify the associations with the presentations of neurodegenerative diseases.

Results: Our work confirmed the association of the E4 allele with a dose-dependent increased presentation of AD, and an association between the E4 allele alone and MCI; however, the other four diseases were not associated with E4. Further, the APOE E2 allele was associated with decreased presentation of both AD and MCI. No associations were identified between MAPT haplotype and the neurodegenerative disease cohorts; but following subtyping of the FTD cohort, the H1 haplotype was significantly associated with progressive supranuclear palsy.

Conclusion: This is the first study to concurrently analyze the association of APOE isoforms and MAPT haplotypes with five neurodegenerative diseases using consistent enrollment criteria and broad phenotypic analysis.
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http://dx.doi.org/10.1017/cjn.2019.228DOI Listing
September 2019

Response to a letter to the editor.

Neurobiol Aging 2019 06 1;78:195-196. Epub 2019 Mar 1.

Department of Neuroscience "Rita Levi Montalcini", University of Torino, Torino, Italy; Neurology 1, Department of Neuroscience and Mental Health, AOU Città della Salute e della Scienza di Torino, Torino, Italy.

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http://dx.doi.org/10.1016/j.neurobiolaging.2019.02.015DOI Listing
June 2019

Heritability and genetic variance of dementia with Lewy bodies.

Neurobiol Dis 2019 07 3;127:492-501. Epub 2019 Apr 3.

Clinical Memory Research Unit, Institution of Clinical Sciences Malmo, Lund University, Sweden.

Recent large-scale genetic studies have allowed for the first glimpse of the effects of common genetic variability in dementia with Lewy bodies (DLB), identifying risk variants with appreciable effect sizes. However, it is currently well established that a substantial portion of the genetic heritable component of complex traits is not captured by genome-wide significant SNPs. To overcome this issue, we have estimated the proportion of phenotypic variance explained by genetic variability (SNP heritability) in DLB using a method that is unbiased by allele frequency or linkage disequilibrium properties of the underlying variants. This shows that the heritability of DLB is nearly twice as high as previous estimates based on common variants only (31% vs 59.9%). We also determine the amount of phenotypic variance in DLB that can be explained by recent polygenic risk scores from either Parkinson's disease (PD) or Alzheimer's disease (AD), and show that, despite being highly significant, they explain a low amount of variance. Additionally, to identify pleiotropic events that might improve our understanding of the disease, we performed genetic correlation analyses of DLB with over 200 diseases and biomedically relevant traits. Our data shows that DLB has a positive correlation with education phenotypes, which is opposite to what occurs in AD. Overall, our data suggests that novel genetic risk factors for DLB should be identified by larger GWAS and these are likely to be independent from known AD and PD risk variants.
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http://dx.doi.org/10.1016/j.nbd.2019.04.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6588425PMC
July 2019

Cerebral perfusion changes in presymptomatic genetic frontotemporal dementia: a GENFI study.

Brain 2019 04;142(4):1108-1120

Hurvitz Brain Sciences Program, Sunnybrook Research Institute, University of Toronto, Toronto, Canada.

Genetic forms of frontotemporal dementia are most commonly due to mutations in three genes, C9orf72, GRN or MAPT, with presymptomatic carriers from families representing those at risk. While cerebral blood flow shows differences between frontotemporal dementia and other forms of dementia, there is limited evidence of its utility in presymptomatic stages of frontotemporal dementia. This study aimed to delineate the cerebral blood flow signature of presymptomatic, genetic frontotemporal dementia using a voxel-based approach. In the multicentre GENetic Frontotemporal dementia Initiative (GENFI) study, we investigated cross-sectional differences in arterial spin labelling MRI-based cerebral blood flow between presymptomatic C9orf72, GRN or MAPT mutation carriers (n = 107) and non-carriers (n = 113), using general linear mixed-effects models and voxel-based analyses. Cerebral blood flow within regions of interest derived from this model was then explored to identify differences between individual gene carrier groups and to estimate a timeframe for the expression of these differences. The voxel-based analysis revealed a significant inverse association between cerebral blood flow and the expected age of symptom onset in carriers, but not non-carriers. Regions included the bilateral insulae/orbitofrontal cortices, anterior cingulate/paracingulate gyri, and inferior parietal cortices, as well as the left middle temporal gyrus. For all bilateral regions, associations were greater on the right side. After correction for partial volume effects in a region of interest analysis, the results were found to be largely driven by the C9orf72 genetic subgroup. These cerebral blood flow differences first appeared approximately 12.5 years before the expected symptom onset determined on an individual basis. Cerebral blood flow was lower in presymptomatic mutation carriers closer to and beyond their expected age of symptom onset in key frontotemporal dementia signature regions. These results suggest that arterial spin labelling MRI may be a promising non-invasive imaging biomarker for the presymptomatic stages of genetic frontotemporal dementia.
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http://dx.doi.org/10.1093/brain/awz039DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6439322PMC
April 2019

Genetic meta-analysis of diagnosed Alzheimer's disease identifies new risk loci and implicates Aβ, tau, immunity and lipid processing.

Nat Genet 2019 03 28;51(3):414-430. Epub 2019 Feb 28.

Research Center and Memory Clinic of Fundació ACE, Institut Català de Neurociències Aplicades-Universitat Internacional de Catalunya, Barcelona, Spain.

Risk for late-onset Alzheimer's disease (LOAD), the most prevalent dementia, is partially driven by genetics. To identify LOAD risk loci, we performed a large genome-wide association meta-analysis of clinically diagnosed LOAD (94,437 individuals). We confirm 20 previous LOAD risk loci and identify five new genome-wide loci (IQCK, ACE, ADAM10, ADAMTS1, and WWOX), two of which (ADAM10, ACE) were identified in a recent genome-wide association (GWAS)-by-familial-proxy of Alzheimer's or dementia. Fine-mapping of the human leukocyte antigen (HLA) region confirms the neurological and immune-mediated disease haplotype HLA-DR15 as a risk factor for LOAD. Pathway analysis implicates immunity, lipid metabolism, tau binding proteins, and amyloid precursor protein (APP) metabolism, showing that genetic variants affecting APP and Aβ processing are associated not only with early-onset autosomal dominant Alzheimer's disease but also with LOAD. Analyses of risk genes and pathways show enrichment for rare variants (P = 1.32 × 10), indicating that additional rare variants remain to be identified. We also identify important genetic correlations between LOAD and traits such as family history of dementia and education.
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http://dx.doi.org/10.1038/s41588-019-0358-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6463297PMC
March 2019

Genome-wide analyses as part of the international FTLD-TDP whole-genome sequencing consortium reveals novel disease risk factors and increases support for immune dysfunction in FTLD.

Acta Neuropathol 2019 06 9;137(6):879-899. Epub 2019 Feb 9.

German Center for Neurodegenerative Diseases (DZNE), 18147, Rostock, Germany.

Frontotemporal lobar degeneration with neuronal inclusions of the TAR DNA-binding protein 43 (FTLD-TDP) represents the most common pathological subtype of FTLD. We established the international FTLD-TDP whole-genome sequencing consortium to thoroughly characterize the known genetic causes of FTLD-TDP and identify novel genetic risk factors. Through the study of 1131 unrelated Caucasian patients, we estimated that C9orf72 repeat expansions and GRN loss-of-function mutations account for 25.5% and 13.9% of FTLD-TDP patients, respectively. Mutations in TBK1 (1.5%) and other known FTLD genes (1.4%) were rare, and the disease in 57.7% of FTLD-TDP patients was unexplained by the known FTLD genes. To unravel the contribution of common genetic factors to the FTLD-TDP etiology in these patients, we conducted a two-stage association study comprising the analysis of whole-genome sequencing data from 517 FTLD-TDP patients and 838 controls, followed by targeted genotyping of the most associated genomic loci in 119 additional FTLD-TDP patients and 1653 controls. We identified three genome-wide significant FTLD-TDP risk loci: one new locus at chromosome 7q36 within the DPP6 gene led by rs118113626 (p value = 4.82e - 08, OR = 2.12), and two known loci: UNC13A, led by rs1297319 (p value = 1.27e - 08, OR = 1.50) and HLA-DQA2 led by rs17219281 (p value = 3.22e - 08, OR = 1.98). While HLA represents a locus previously implicated in clinical FTLD and related neurodegenerative disorders, the association signal in our study is independent from previously reported associations. Through inspection of our whole-genome sequence data for genes with an excess of rare loss-of-function variants in FTLD-TDP patients (n ≥ 3) as compared to controls (n = 0), we further discovered a possible role for genes functioning within the TBK1-related immune pathway (e.g., DHX58, TRIM21, IRF7) in the genetic etiology of FTLD-TDP. Together, our study based on the largest cohort of unrelated FTLD-TDP patients assembled to date provides a comprehensive view of the genetic landscape of FTLD-TDP, nominates novel FTLD-TDP risk loci, and strongly implicates the immune pathway in FTLD-TDP pathogenesis.
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http://dx.doi.org/10.1007/s00401-019-01962-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6533145PMC
June 2019

Diagnostic delay in Parkinson's disease caused by PRKN mutations.

Parkinsonism Relat Disord 2019 06 10;63:217-220. Epub 2019 Jan 10.

Edmond J. Safra Program in Parkinson's Disease, Morton and Gloria Shulman Movement Disorders Clinic, Toronto Western Hospital, UHN, Toronto, Ontario, Canada; Division of Neurology, University of Toronto, Toronto, Ontario, Canada; Krembil Brain Institute, Toronto, Ontario, Canada. Electronic address:

Objective: To confirm that there is a diagnostic delay in Parkin-related Parkinson Disease and to explore possible factors causing such a delay.

Methods: We retrospectively analyzed our patients with mutations in the parkin RBR E3 ubiquitin protein ligase gene (PRKN). We collected a total of 34 patients and focused on 18 cases (14 homozygous, 4 compound heterozygous). An arbitrary cut-off of 10 years from disease onset to diagnosis was considered to define patients with delayed diagnosis.

Results: Eight of 18 cases had a significant delay in their diagnosis (25.3 ± 17 years). By comparing patients with and without a delayed diagnosis and subsequently, comparing these groups to a group of young onset PD negative for mutations of PRKN, SNCA, DJ1, PINK1, LRRK2, GBA, and ATP13A2, we identified a specific phenotype associated with a diagnostic delay: young age, lack of tremor, and involvement of lower limbs (particularly dystonia affecting gait) at the time of disease onset.

Conclusions: Our findings emphasize the diverse phenotypes associated with PRKN mutations and the related diagnostic challenges they present.
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http://dx.doi.org/10.1016/j.parkreldis.2019.01.010DOI Listing
June 2019

A comprehensive screening of copy number variability in dementia with Lewy bodies.

Neurobiol Aging 2019 03 24;75:223.e1-223.e10. Epub 2018 Oct 24.

Human Genetics, School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham, UK.

The role of genetic variability in dementia with Lewy bodies (DLB) is now indisputable; however, data regarding copy number variation (CNV) in this disease has been lacking. Here, we used whole-genome genotyping of 1454 DLB cases and 1525 controls to assess copy number variability. We used 2 algorithms to confidently detect CNVs, performed a case-control association analysis, screened for candidate CNVs previously associated with DLB-related diseases, and performed a candidate gene approach to fully explore the data. We identified 5 CNV regions with a significant genome-wide association to DLB; 2 of these were only present in cases and absent from publicly available databases: one of the regions overlapped LAPTM4B, a known lysosomal protein, whereas the other overlapped the NME1 locus and SPAG9. We also identified DLB cases presenting rare CNVs in genes previously associated with DLB or related neurodegenerative diseases, such as SNCA, APP, and MAPT. To our knowledge, this is the first study reporting genome-wide CNVs in a large DLB cohort. These results provide preliminary evidence for the contribution of CNVs in DLB risk.
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http://dx.doi.org/10.1016/j.neurobiolaging.2018.10.019DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6541211PMC
March 2019

Parkinsonism due to A53E α-synuclein gene mutation: Clinical, genetic, epigenetic, and biochemical features.

Mov Disord 2018 12 13;33(12):1950-1955. Epub 2018 Nov 13.

Edmond J. Safra Program in Parkinson's Disease and Morton and Gloria Shulman Movement Disorders Clinic, Division of Neurology, Department of Medicine, Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada.

Background: SNCA mutations cause autosomal dominant parkinsonism and inform our understanding of the molecular underpinnings of synucleinopathies. The most recently identified mutation, p.Ala53Glu (A53E), has only been observed in Finland. The objectives of this study were to examine clinical, genetic, epigenetic, and biochemical features of the first family outside Finland with A53E.

Methods: We examined a Canadian family with parkinsonism because of A53E using haplotype and DNA methylation analyses. We assessed aggregation properties of A53E α-synuclein in vitro.

Results: Family members with parkinsonism shared a common haplotype distinct from Finnish patients with A53E. Increased acceleration of DNA methylation age was accompanied by earlier age at onset in the family members. We demonstrate that A53E α-synuclein has a propensity to form oligomers and phosphorylation promotes fibrillation.

Conclusions: A53E as a cause of parkinsonism is not restricted to Finnish individuals. DNA methylation may contribute to disease age at onset. A53E enriches α-synuclein oligomers and fibrils dependent on the phosphorylation state. © 2018 International Parkinson and Movement Disorder Society.
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http://dx.doi.org/10.1002/mds.27506DOI Listing
December 2018

A C6orf10/LOC101929163 locus is associated with age of onset in C9orf72 carriers.

Brain 2018 10;141(10):2895-2907

Neurodegenerative Brain Diseases, Center of Molecular Neurology, VIB, Antwerp, Belgium.

The G4C2-repeat expansion in C9orf72 is the most common known cause of amyotrophic lateral sclerosis and frontotemporal dementia. The high phenotypic heterogeneity of C9orf72 patients includes a wide range in age of onset, modifiers of which are largely unknown. Age of onset could be influenced by environmental and genetic factors both of which may trigger DNA methylation changes at CpG sites. We tested the hypothesis that age of onset in C9orf72 patients is associated with some common single nucleotide polymorphisms causing a gain or loss of CpG sites and thus resulting in DNA methylation alterations. Combined analyses of epigenetic and genetic data have the advantage of detecting functional variants with reduced likelihood of false negative results due to excessive correction for multiple testing in genome-wide association studies. First, we estimated the association between age of onset in C9orf72 patients (n = 46) and the DNA methylation levels at all 7603 CpG sites available on the 450 k BeadChip that are mapped to common single nucleotide polymorphisms. This was followed by a genetic association study of the discovery (n = 144) and replication (n = 187) C9orf72 cohorts. We found that age of onset was reproducibly associated with polymorphisms within a 124.7 kb linkage disequilibrium block tagged by top-significant variation, rs9357140, and containing two overlapping genes (LOC101929163 and C6orf10). A meta-analysis of all 331 C9orf72 carriers revealed that every A-allele of rs9357140 reduced hazard by 30% (P = 0.0002); and the median age of onset in AA-carriers was 6 years later than GG-carriers. In addition, we investigated a cohort of C9orf72 negative patients (n = 2634) affected by frontotemporal dementia and/or amyotrophic lateral sclerosis; and also found that the AA-genotype of rs9357140 was associated with a later age of onset (adjusted P = 0.007 for recessive model). Phenotype analyses detected significant association only in the largest subgroup of patients with frontotemporal dementia (n = 2142, adjusted P = 0.01 for recessive model). Gene expression studies of frontal cortex tissues from 25 autopsy cases affected by amyotrophic lateral sclerosis revealed that the G-allele of rs9357140 is associated with increased brain expression of LOC101929163 (a non-coding RNA) and HLA-DRB1 (involved in initiating immune responses), while the A-allele is associated with their reduced expression. Our findings suggest that carriers of the rs9357140 GG-genotype (linked to an earlier age of onset) might be more prone to be in a pro-inflammatory state (e.g. by microglia) than AA-carriers. Further, investigating the functional links within the C6orf10/LOC101929163/HLA-DRB1 pathway will be critical to better define age-dependent pathogenesis of frontotemporal dementia and amyotrophic lateral sclerosis.
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http://dx.doi.org/10.1093/brain/awy238DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6158742PMC
October 2018