ARTICLE OPEN ACCESS C9orf72, age at onset, and ancestry help discriminate behavioral from language variants in FTLD cohorts Beatrice Costa, BSc, Claudia Manzoni, PhD, Manuel Bernal-Quiros, PhD, Demis A. Kia, MD, Miquel Aguilar, MD, Correspondence Ignacio Alvarez, MSc, Victoria Alvarez, PhD, Ole Andreassen, MD, PhD, Maria Anfossi, PhD, Silvia Bagnoli, PhD, Dr. Ferrari Luisa Benussi, PhD, Livia Bernardi, PhD, Giuliano Binetti, MD, Daniel Blackburn, MD, PhD, r.ferrari@ucl.ac.uk Mercè Boada, MD, PhD, Barbara Borroni, MD, Lucy Bowns, Geir Bråthen, MD, PhD, Amalia C. Bruni, MD, or Dr. Manzoni Huei-Hsin Chiang, PhD, Jordi Clarimon, PhD, Shuna Colville, MSc, Maria E. Conidi, PhD, Tom E. Cope, MD, PhD, c.manzoni@ucl.ac.uk Carlos Cruchaga, PhD, Chiara Cupidi, MD, Maria Elena Di Battista, MD, PhD, Janine Diehl-Schmid, MD, Monica Diez-Fairen, MSc, Oriol Dols-Icardo, PhD, Elisabetta Durante, PhD, Dušan Flisar, MD, Francesca Frangipane, MD, Daniela Galimberti, PhD, Maura Gallo, PhD, Maurizio Gallucci, MD, Roberta Ghidoni, PhD, Caroline Graff, MD, PhD, Jordan H. Grafman, PhD, Murray Grossman, MD, John Hardy, PhD, Isabel Hernández, MD, PhD, Guy J.T. Holloway, MBBS, Edward D. Huey, MD, Ignacio Illán-Gala, MD, PhD, Anna Karydas, MSc, Behzad Khoshnood, PhD, Milica G. Kramberger, MD, PhD, Mark Kristiansen, PhD, Patrick A. Lewis, PhD, Alberto Lleó, MD, PhD, Gaganjit K. Madhan, MSc, Raffaele Maletta, MD, Aleš Maver, MD, PhD, Manuel Menendez-Gonzalez, MD, PhD, Graziella Milan, MD, Bruce Miller, MD, Merel O. Mol, MSc, Parastoo Momeni, PhD, Sonia Moreno-Grau, PhD, Chris M. Morris, PhD, Benedetta Nacmias, PhD, Christer Nilsson, MD, Valeria Novelli, PhD, Linn Öijerstedt, MD, Alessandro Padovani, MD, Suvankar Pal, MBBS, MRCP, MD, Yasmin Panchbhaya, MSc, Pau Pastor, MD, PhD, Borut Peterlin, MD, PhD, Irene Piaceri, PhD, Stuart Pickering-Brown, PhD, Yolande A.L. Pijnenburg, MD, PhD, Annibale A. Puca, MD, Innocenzo Rainero, MD, PhD, Antonella Rendina, PhD, Anna M.T. Richardson, FRCP, Ekaterina Rogaeva, PhD, Boris Rogelj, PhD, Sara Rollinson, PhD, Giacomina Rossi, PhD, Carola Rossmeier, MD, James B. Rowe, MD, PhD, Elisa Rubino, MD, PhD, Agustı́n Ruiz, MD, PhD, Raquel Sanchez-Valle, MD, PhD, Sigrid B. Sando, PhD, Alexander F. Santillo, MD, PhD, Jennifer Saxon, MSc, Elio Scarpini, MD, Maria Serpente, PhD, Nicoletta Smirne, BSc, Sandro Sorbi, MD, EunRan Suh, PhD, Fabrizio Tagliavini, MD, Jennifer C. Thompson, PhD, John Q. Trojanowski, MD, PhD, Vivianna M. Van Deerlin, MD, PhD, Julie Van der Zee, PhD, Christine Van Broeckhoven, DSc, PhD, Jeroen van Rooij, John C. Van Swieten, MD, Arianna Veronesi, MD, PhD, Emilia Vitale, PhD, Maria L. Waldö, MD, PhD, Cathy Woodward, MSc, Jennifer Yokoyama, PhD, Valentina Escott-Price, PhD, James M. Polke, PhD, and Raffaele Ferrari, PhD, for the International FTD-Genetics Consortium ® Neurology 2020;95:e3288-e3302. doi:10.1212/WNL.0000000000010914 Abstract Objective We sought to characterize C9orf72 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 C9orf72 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% [p = 2.17 × 10−5; odds e3288 Copyright © 2020 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology. 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% [p = 1.1 × 10−2; 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 C9orf72 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. 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., Agustı́n 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 Clı́nic 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., Agustı́n 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. International FTD-Genetics Consortium (IFGC) coinvestigators are listed at links.lww.com/WNL/B240. Go to Neurology.org/N for full disclosures. Funding information and disclosures deemed relevant by the authors, if any, are provided at the end of the article. The Article Processing Charge was funded by MRC and Wellcome Trust. This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (CC BY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Neurology.org/N Neurology | Volume 95, Number 24 | December 15, 2020 e3289 Glossary AAO = age at onset; bvFTD = behavioral variant frontotemporal dementia; FTLD = frontotemporal lobar degeneration; IFGC = International FTD Genetics Consortium; LOOCV = leave-one-out cross-validation; MND = motor neuron disease; PCA = principal components analysis; PNFA = progressive nonfluent aphasia; PPA = primary progressive aphasia; rc = repeat counts; SNP = single nucleotide polymorphism. Frontotemporal lobar degeneration (FTLD) refers to the current study is approved under institutional review board second most common form of young-onset dementia after approval 9811/001. Alzheimer disease.1 The major clinical syndromes are be- havioral variant frontotemporal dementia (bvFTD)2 or lan- Cohort, clinical phenotyping guage dysfunctions, broadly called primary progressive FTLD cases were collected between 2016 and 2018 (within aphasia (PPA); the latter is subdivided into semantic de- the IFGC phase III project [ifgcsite.wordpress.com/on- mentia or semantic variant PPA and progressive nonfluent going-projects/]). The samples were recruited by clinicians aphasia (PNFA) or nonfluent/agrammatic variant PPA.2,3 and research groups who are part of the IFGC network and FTLD can also occur together with motor neuron disease based in Italy, Spain, Germany, the Netherlands, Belgium, (MND) or amyotrophic lateral sclerosis in a continuous the United Kingdom, Sweden, Norway, Slovenia, or the spectrum of phenotypes.4 United States (supplementary table 1, doi.org/10.5522/ 04/12418157). Patients were diagnosed at each contrib- In FTLD, repeat expansions in C9orf725 have been previously uting site (supplementary table 2, doi.org/10.5522/04/ reported to occur in ;25%6–10 of familial and ;6%11 of 12418157) in a harmonized fashion according to in- sporadic cases (i.e., individuals with no clear familial history or ternational consensus criteria such as those of Neary et al.2 genetic aetiology12). Several studies had shown high fre- (for FTLD), Rascovsky et al.25 (for bvFTD), Gorno- quencies of pathogenic C9orf72 expansions in Northern vs Tempini et al.3 (for PPA [semantic dementia or PNFA]), Southern European patients (North–South axis), especially in and Strong et al.4 (for FTLD-MND). historically isolated populations (such as the Finnish13,14), leading to the hypothesis that a Scandinavian founder might Genotyping, C9orf72 repeat expansions, and be at the basis of the spread of the C9orf72 expansion.15 Other analysis cohorts studies (based on the geographic location of the recruiting A total of 1,454 cases were successfully genotyped by means of sites) challenged the North–South axis concept, reporting a the NeuroArray26 on the Illumina Infinium platform. Geno- high frequency (;25%) of pathogenic expansions in the types were used to inform on population substructure via Spanish population10 or implying to the existence of more standard principal components analysis (PCA) (supplemen- than 1 risk haplotype.16–19 tary figure 1, doi.org/10.5522/04/12418157), which led to the exclusion of 44 population outliers, and allowed us to address Patients with FTLD with abnormal C9orf72 repeat expan- population substructure within the cohort (we identified 2 sions exhibit marked phenotypic and pathologic heteroge- distinct [Nordic and Mediterranean] clusters; supplementary neity, suggesting presence of additional (genetic and figure 2, doi.org/10.5522/04/12418157). We also assessed environmental) modifiers.20 Despite conflicting studies cryptic relatedness and excluded 14 first- or second-degree reporting either direct or inverse correlation between repeat related individuals, leaving a cohort of 1,396 cases (group length and age at onset (AAO), C9orf72 expansions have been 0)—for which C9orf72 expansion status (i.e., presence/ suggested to act as a genetic modifier of AAO.16,21–24 absence of pathogenic expansions) was known—for analy- ses. Frequencies of pathogenic expansions were assessed in We analyzed 1,396 FTLD cases gathered through the In- group 0 and further analyses were performed in (1) 1,295 cases ternational FTD Genetics Consortium (IFGC) (ifgcsite.word- (group 1: n = 800 bvFTD and n = 495 PPA) with known press.com/) phase III initiative, aiming at (1) characterizing C9orf72 expansion status; (2) 1,179 cases (group 2; n = 756 C9orf72 expansions in relation to genetic ancestry and AAO and bvFTD and n = 423 PPA) with known C9orf72 expansion (2) assessing the usefulness of these measures in discriminating status and AAO data available; and (3) 734 cases (group 3; n = the behavioral from the language variant syndrome. 462 bvFTD and n = 272 PPA) with AAO and repeat counts (rc; screened via repeat-primed PCR) (see references 27 and 28; supplementary Methods and supplementary figure 3, doi. Methods org/10.5522/04/12418157; and figure 1A). Standard protocol approvals, registrations, Statistical analyses and patient consents We first assessed the frequency of pathogenic expansions in the Each contributing site obtained written informed consent entire cohort (group 0). The information on presence/absence from all patients to be part of extended genetic studies; the of expansions was used as a binary variable (0 = absence of e3290 Neurology | Volume 95, Number 24 | December 15, 2020 Neurology.org/N Figure 1 Cohorts and analysis workflow (A) Cohorts. (B) Analysis workflow. K-fold regression model. AAO = age at onset; ANOVA = analysis of variance; bvFTD = behavioral variant frontotemporal dementia; FTLD = frontotemporal lobar degeneration; logistic/cluster = logistic regression using cluster as covariate; logistic/PC1 = logistic regression using PC1 as covariate; LOOCV = leave-one-out cross-validation regression model; MND = motor neuron disease; PPA = primary progressive aphasia. expansion; 1 = presence of expansion). We then investigated [LOOCV] and the K-fold models). A summary of the anal- differences in the frequencies of pathogenic expansions across yses workflow can be found in figure 1B. bvFTD and PPA and the Nordic and Mediterranean clusters in group 1 (Fisher exact test) and in group 3 (logistic regression); All analyses were performed using R studio (version 3.6.0, in the latter, we used rc as a categorical variable (using no, short, studio version 1.2.1335). intermediate, and long as factor levels) considering the follow- ing 4 categories: no expansions (rc = 2/3), short expansions C9orf72 locus risk haplotype (4 ≤ rc ≤ 8), intermediate expansions (9 ≤ rc ≤ 24), and long Twenty (rs1110264, rs1110155, rs2150336, rs1161680, expansions (rc ≥ 25), the latter representing expansions in the rs2589054, rs1822723, rs4879515, rs895023, rs868856, pathogenic range (see references 10 and 22, supplementary rs1977661, rs903603, rs12349820, rs10122902, rs2282241, Methods, and supplementary figure 3, doi.org/10.5522/04/ rs1948522, rs1982915, rs2453556, rs702231, rs696826, and 12418157). rs247751) of the original 42 single nucleotide polymor- phisms (SNPs) constituting the (Finnish) risk haplotype29 We then evaluated association between AAO and syndrome, were available on the NeuroArray.26 We filtered out 7 genetic ancestry, and expansions (i.e., presence/absence used markers in order to keep 13 informative SNPs (rs1822723, as a binary variable; see above) alone and with genetic an- rs4879515, rs868856, rs1977661, rs903603, rs10122902, cestry as a covariate in group 2 (t test and logistic regression) rs2282241, rs1948522, rs1982915, rs2453556, rs702231, and in group 3 (t test, analysis of variance with Tukey post hoc rs696826, and rs2477518) matching 13 of the 20 used in test, and logistic and linear mixed-effects model). In the latter Mok et al.15 We evaluated the proportion of cases carrying at case, we used rc as a categorical variable (see above). least 1 risk allele (as in Mok et al.15) for each marker assessing expansion vs nonexpansion carriers (with/without Finally, we sought to build a model to predict syndrome ancestry stratification). (bvFTD vs PPA) using (1) presence/absence of pathogenic expansions (as binary variable [see above] for group 2) or (2) Data availability rc (as categorical variable [see above] for group 3), ancestry as All data generated or analyzed during this study are included binary variable, and AAO as continuous variable using logistic in this published article and supplementary files 1 and 2 at doi. regression models (i.e., the leave-one-out cross-validation org/10.5522/04/12418157. Neurology.org/N Neurology | Volume 95, Number 24 | December 15, 2020 e3291 Results Table 2 Frequency of expansion carriers in the Nordic C9orf72 expansions frequency and syndromes and Mediterranean clusters We assessed the frequency of pathogenic expansions in the Genetic ancestry Cases, n Expansion carriers Frequency, % entire cohort and across the different syndromes in the group 0 cases (figure 1). Four percent of all cases (56/1,396 [4%]) Nordic 795 35 4.4a carried pathogenic expansions. These were most frequent in Mediterranean 500 9 1.8a FTLD-MND (12/101 [11.9%]) followed by bvFTD (40/800 [5%]) and PPA (4/495 [0.8%]). The higher prevalence of The higher prevalence of expansion carriers in the Nordic vs the Mediter- ranean cluster is statistically significant: aFisher exact test: p = 1.1 × 10−2; pathogenic expansions in bvFTD vs PPA was statistically odds ratio 2.5; 95% confidence interval 1.17–5.99. significant (Fisher exact test: p = 2.17 × 10−5; OR 6.4; 95% CI 2.31–24.99, table 1). We further explored this finding in the group 3 cases using logistic regression to assess association We observed a significantly higher prevalence of pathogenic between expansion length (represented by 4 rc factor levels: expansions in the Nordic (35/795 [4.4%]) vs the Mediter- short, intermediate, and long expansions, tested against no ranean (9/500 [1.8%]) cluster (Fisher exact test: p = 1.1 × expansions) and syndromes (bvFTD vs PPA). Expansion 10−2; OR 2.5; CI 1.17–5.99, table 2). We further evaluated length discriminated bvFTD from PPA with a trend that was this finding in the group 3 cases using logistic regression to significant in the intermediate (p = 4.7 × 10−2; OR 1.6; CI assess association between expansion length (see above) and 0.0061 [2.5%]–0.94 [97.5%]) and long (p = 1.9 × 10−3; OR genetic ancestry. Expansion length discriminated the Nordic 7.2; CI 0.86 [2.5%]–3.45 [97.5%]) rc ranges (with a ;90% from Mediterranean cluster with a trend that was significant in probability of a bvFTD diagnosis supported by the latter; the intermediate (p = 9.7 × 10−4, OR 2.2; CI 0.32 [2.5%]–1.25 supplementary table 3, doi.org/10.5522/04/12418157). [97.5%]) and long (p = 4.7 × 10−4, OR 9.3; CI 1.12 [2.5%]–3.7 [97.5%]) rc ranges (with a ;90% probability of C9orf72 expansions (and rc) and Nordic ancestry supported by the latter; supplementary table genetic ancestry 4, doi.org/10.5522/04/12418157). We performed PCA (PC1 vs PC2, supplementary figure 2A; PC1 vs PC3, supplementary figure 2B, doi.org/10.5522/04/ Provided differences in syndromes prevalence and distribu- 12418157) to cluster the group 1 cases based on their genetic tion across the Nordic and Mediterranean clusters—bvFTD makeup. There were 2 major clusters: cluster 1 (Mediterra- (469/795 [59%] vs 331/500 [66.2%]) and PPA (326/795 nean) included most of the cases (439/500 [87.8%]) [41%] vs 169/500 [33.8%]), respectively (supplementary recruited from Southern European sites (Italy and Spain); table 5, doi.org/10.5522/04/12418157)—we analyzed the cluster 2 (Nordic) included most of the cases (627/795 distribution of pathogenic expansions across syndromes and [78.8%]) recruited from Central and Northern European sites clusters. Stratified Fisher exact test showed significant differ- (Belgium, the Netherlands, Germany, the United Kingdom, ences in the distribution of the pathogenic expansions be- Norway, and Sweden). Samples recruited from Eastern Eu- tween bvFTD and PPA in the Nordic (but not the ropean (Slovenia) and North American sites distributed Mediterranean) cluster (p = 1 × 10−4; OR 7.87; 95% CI across both clusters, although with a higher prevalence within 2.43–40.52), and between the Nordic and the Mediterranean cluster 2 (167/795 [21%]) vs cluster 1 (42/500 [8.4%]). clusters for the bvFTD (but not PPA) syndrome (p = 1.9 × 10−2; OR 2.95; 95% CI 1.31–7.52), suggesting that ancestry (Nordic) and syndrome (bvFTD) are independently associ- ated with pathogenic expansions (table 3). Table 1 Frequency of expansion carriers in the entire cohort and by syndrome C9orf72 repeat expansions (and counts [rc]) Cohort Cases, n Expansion carriers Frequency, % and AAO We assessed AAO in the group 2 cases (figure 1). Mean AAO bvFTD 800 40 5a was significantly different between the bvFTD (61.7) and PPA 495 4 0.8a PPA (64) syndromes (t test: p = 1.86 × 10−5; CI −3.34 to FTLD-MND 101 12 11.9 −1.25) and the Nordic (61.3) and Mediterranean (64.3) clusters (t test: p = 1.16 × 10−7; CI 1.86–4.03) (figure 2A and Total 1,396 56 4 supplementary table 6, A and B, doi.org/10.5522/04/ Abbreviations: bvFTD = behavioral variant frontotemporal dementia; FTLD = 12418157). We then assessed the relationship between frontotemporal lobar degeneration; MND = motor neuron disease; PPA = pathogenic expansions and AAO via logistic regression. First, primary progressive aphasia. Summary of expansion carrier frequency in the entire cohort (n = 1,396) and we identified a significant correlation between a decrease in across syndromes. The higher prevalence of expansion carriers in bvFTD vs AAO and presence of pathogenic expansions (p = 7.7 × 10−4; PPA is statistically significant: aFisher exact test performed to statistically evaluate the difference between the occurrence of pathogenic expansions R2 = 0.008; CI −8.05 [2.5%] to −2.13 [97.5%]). When we in bvFTD vs PPA: p = 2.17 × 10−5; odds ratio 6.4; 95% confidence interval included genetic ancestry in the model, we observed a sig- 2.31–24.99. nificant correlation with a decrease in AAO, with no difference e3292 Neurology | Volume 95, Number 24 | December 15, 2020 Neurology.org/N Table 3 Stratified Fisher exact tests comparing prevalence of pathogenic expansions across behavioral variant frontotemporal dementia (bvFTD) and primary progressive aphasia (PPA) and the Nordic and Mediterranean clusters Expansion range Pathogenic Nonpathogenic Fisher exact test Subtype/ancestry bvFTD Mediterranean 8 323 p = 1.9 × 10−2a Nordic 32 437 Ancestry/subtype Mediterranean bvFTD 8 323 p=1 PPA 1 168 Nordic bvFTD 32 437 p = 1 × 10−4b PPA 3 323 p Values presented in the table are corrected for multiple testing statistics. Prior correction p values were as follows: a(uncorrected) Fisher exact test: p = 4.7 × 10−3; odds ratio 2.95; 95% confidence interval 1.31–7.52: significant difference in the prevalence of bvFTD expansion carriers in the Nordic vs the Mediterranean cluster; b(uncorrected) Fisher exact test p = 2.7 × 10−5; odds ratio 7.87; 95% confidence interval 2.43–40.52: significant difference in the prevalence of expansion carriers in bvFTD vs PPA within the Nordic cluster. in using either cluster (p = 2.3 × 10−3; CI −7.5 [2.5%] to −1.63 −0.23 for long vs no expansions) (supplementary table 8D, [97.5%] for pathogenic expansions; p = 2.3 × 10−7; CI −3.9 figure 2B and C: doi.org/10.5522/04/12418157). We then [2.5%] to −1.77 [97.5%] for cluster; R2 = 0.03) or PC1 (p = assessed the relationship between expansion length (see 2.1 × 10−3; CI −7.5 [2.5%] to −1.66 [97.5%] for pathogenic above) and AAO via logistic regression. First, we identified a expansions; p = 6.4 × 10−7; CI 30.1 [2.5%]–68.9 [97.5%] for significant correlation between a decrease in AAO and both PC1; R2 = 0.028) as covariate and an almost 4-fold goodness intermediate and long expansions (p = 4 × 10−2; CI −4.36 of fit increase (supplementary table 7, A–C, doi.org/10.5522/ [2.5%] to −0.96 [97.5%] for intermediate and p = 7 × 10−3; 04/12418157). Of note, when comparing the 2 regression CI −9.05 [2.5%] to −1.43 [97.5%] for long expansions; R2 = models (with/without genetic ancestry as covariate) through 0.017) (supplementary table 9A, doi.org/10.5522/04/ the log-likelihood R2 ratio test, the difference (between the 2 12418157). When we included genetic ancestry in the models) appeared not to be due to chance (p < 10−12) model, we observed a significant correlation with a decrease (supplementary table 7, B and C, doi.org/10.5522/04/ in AAO, no difference in using either cluster (p = 4.7 × 12418157). 10−2; CI −7.65 [2.5%] to −0.05 [97.5%] for long vs no expansion; p = 2.38 × 10−6; CI −4.73 [2.5%] to −1.97 We further evaluated the relationship between expansion [97.5%] for cluster; R2 = 0.045) or PC1 (p = 5.98 × 10−2; CI length (represented by 4 rc factor levels—short, in- −7.5 [2.5%] to 0.14 [97.5%] for long vs no expansion; p = termediate, and long expansions, tested against no expan- 1.2 × 10−6; CI 39.8 [2.5%] –92.9 [97.5%] for PC1; R2 = sions) and AAO in the group 3 cases (figure 1). First, we 0.047) as covariate and an almost 3-fold goodness of fit independently analyzed association between AAO and (1) increase (supplementary table 9, A–C, doi.org/10.5522/ genetic ancestry—mean AAO 60.9 and 64.6 in the Nordic 04/12418157). Of note, when comparing the 2 regression and Mediterranean cluster, respectively (t test: p = 2.1 × models (with/without genetic ancestry as covariate) 10−7; CI 2.32–5.09; supplementary table 8A, doi.org/10. through the log-likelihood R2 ratio test, the difference 5522/04/12418157); (2) syndrome—mean AAO 61.7 (between the 2 models) appeared not to be due to chance and 63.5 in the bvFTD and PPA syndromes, respectively (p < 10−12) (supplementary table 9, B and C, doi.org/10. (t test: p = 9.1 × 10−3; CI −3.11 to −0.44; supplementary 5522/04/12418157). These findings were further sup- table 8B, doi.org/10.5522/04/12418157), and (3) expan- ported by nonlinear mixed-effects model regression using sion length—mean AAO 63.2 for both no and short ex- genetic ancestry as random effect covariate (for long vs no pansions, 61 for intermediate expansions, and 58 for long expansion; see supplementary table 10, doi.org/10.5522/ expansions (analysis of variance p = 3.6 × 10−2; CI −10.2 to 04/12418157). Neurology.org/N Neurology | Volume 95, Number 24 | December 15, 2020 e3293 Figure 2 Association between age at onset (AAO) and ancestry, syndrome, and expansion length (A) AAO in the group 2 cases. Mean AAO behavioral variant frontotemporal dementia (bvFTD) (61.7) and primary progressive aphasia (PPA) (64) (t test: p = 1.86 × 10−5; confidence interval [CI] −3.34 to 1.25); mean AAO Nordic (61.3) and Mediterranean (64.3) clusters (t test: p = 1.16 × 10−7; CI 1.86–4.03). (B) AAO in the group 3 cases. Mean AAO bvFTD (61.7) and PPA (63.5) (t test: p = 9.1 × 10−3; CI −3.11 to 0.44); mean AAO Nordic (60.9) and Mediterranean (64.6) (t test: p = 2.1 × 10−7; CI 2.32–5.09). (C) AAO in the group 3 cases. Mean AAO for both no and short expansions (63.2), for intermediate expansions (61), and for long expansions (58) evaluated via analysis of variance test. C9orf72 locus risk haplotype proxy: the risk allele segregated differently across expan- All of the risk alleles for the 13 markers—shortest in- sion vs nonexpansion carriers in the Nordic and Mediter- formative stretch of the original risk haplotype15,29 avail- ranean cluster (as for rs2453556), possibly suggesting these able to us—were seen in (1) 40/56 (71.4%) expansion 2 as the most conserved markers of the original risk hap- carriers vs 380/1,340 (28.4%) nonexpansion carriers in the lotype across populations in expansion carriers (high- entire cohort; (2) 33/47 (70.2%) expansion carriers vs lighted in blue in supplementary figure 4, doi.org/10.5522/ 228/826 (27.6%) nonexpansion carriers in the Nordic 04/12418157). cluster; and (3) 7/9 (77.8%) expansion carriers vs 152/514 (29.6%) nonexpansion carriers in the Mediterranean clus- Syndrome prediction ter. Comparing the proportion of risk allele carriers (ex- We then sought to build a model to predict syndrome pansion vs nonexpansion carriers) for each single marker, (bvFTD vs PPA) and assess its accuracy. We analyzed both 5/13 markers (rs4879515, rs868856, rs903603, rs2282241, groups 2 and 3 cases using expansion status (presence/ rs2453556) were significant in the Nordic cluster, and none absence of expansion for group 2 and the 4 rc factor in the Mediterranean cluster (supplementary figure 4, doi. levels for group 3 [see Methods]), genetic ancestry org/10.5522/04/12418157). Rs2477518 showed variable (using either cluster or PC1) as binary variables, and AAO frequencies for the risk allele (T) across expansion vs as a continuous variable in logistic regression models. nonexpansion carriers (and the 2 clusters), thus making We observed an accuracy of ;0.64 (group 2; supple- this most probably a negligible marker within this stretch, mentary table 11, doi.org/10.5522/04/12418157) and as hinted previously.15,17 Rs3849942, previously suggested ;0.62 (group 3; supplementary table 12, doi.org/ as a surrogate marker for the risk haplotype,15 was not 10.5522/04/12418157) in predicting bvFTD; there among the SNPs available to us. We used rs868856, dis- were no differences in the outcome when using either playing strongest linkage disequilibrium with rs3849942 cluster or PC1 as covariates in both (LOOCV and K-fold) (D’ = 0.96; R2 = 0.7; ldlink.nci.nih.gov/), as informative models. e3294 Neurology | Volume 95, Number 24 | December 15, 2020 Neurology.org/N Discussion Figure 3 Patient subpopulations (behavioral variant fron- This study aimed to characterize C9orf72 expansions in re- totemporal dementia [bvFTD] and primary pro- lation to genetic ancestry and AAO and to assess the useful- gressive aphasia [PPA] syndromes) based on ness of these measures in discriminating the behavioral from C9orf72 expansion genetic signatures and ancestry the language variant syndrome in a large pan-European cohort of 1,396 FTLD cases. To our knowledge, the current work is unique in that, prior to characterizing the expansions, we excluded population- substructure bias using genome-wide genotyping data to cluster the cases on the basis of their genetic makeup. After PCA, we identified 2 distinct clusters including samples with geographic ancestry corresponding to Southern Europe (Mediterranean cluster) and Central/Northern Europe (Nordic cluster). Our analyses not only showed that patients from the Nordic cluster presented significantly higher fre- quency of pathogenic C9orf72 expansions compared to the Mediterranean cluster, but also that a core stretch of markers (n = 8) of the Finnish risk haplotype29 appeared to be con- served across the Nordic expansion carriers, whereas there possibly implying a more complex genetic signature (or ar- was a similar tendency for (just) 2 of such markers in the chitecture), and subsequently molecular mechanisms, un- Mediterranean expansion carriers. Several studies had shown derpinning this feature. Clearly, disease mechanisms that high frequencies of long C9orf72 expansions in Northern vs involve C9orf72 expansion length and AAO are complex, thus Southern European patients (North–South axis).13–15 Other it is likely that additional factors might further modulate their studies (based on the geographic location of the recruiting relationship and effect on the phenotype (see also Babić Leko sites) challenged the North–South axis concept,10 or the et al.5). founder effect implying the existence of more than 1 risk haplotype.16–19 All this taken together, our current data ap- While using expansion length, genetic ancestry, and AAO in a pear to support the North–South axis hypothesis and suggest regression model to discriminate behavioral from language that rearrangements (and instability)16,19 at the C9orf72 locus variant subtypes, we found that such measures supported a might have occurred, reducing the level of conservation of the prediction of bvFTD with 64% accuracy. original risk haplotype across the European population. Our results have a number of implications. First, provided that We found pathogenic expansions in ;4% of all cases and that the significant variation exists in the genetic architecture of the proportion of expansion carriers was significantly higher in Caucasian population,35 genetic variability characterizing and bvFTD compared to PPA. The fact that we overall identified differentiating Nordic vs Mediterranean subjects (such as in significant association between pathogenic expansions and a di- the case of our cohort) might influence predisposition to agnosis of bvFTD and Central/Northern European ancestry— harboring longer repeat expansions. In other repeat expansion findings in line with previous reports8,10,13,20,30–34—suggests that diseases—e.g., Huntington disease or other microsatellite C9orf72 expansions might serve as useful genetic fingerprint to diseases, including myotonic dystrophy and spinocerebellar define subpopulations of FTLD (figure 3). Of note, we observed ataxias35—the presence of specific haplogroups in Western a trend of association with syndrome (bvFTD) and genetic an- European populations occurs with a manifold increase in cestry (Central/Northern European) already supported by the prevalence of repeats compared to other ethnic groups and intermediate repeat counts (9 ≤ rc ≤ 24) category. This appears in populations.36 Second, different genetic risk architectures line with previous reports suggesting that individuals with 7–24 underpinning different (and possibly genetically more ho- alleles might have an increased risk to convert to carriers of mogeneous) subpopulations of patients may exist within the pathologic repeat expansions10,22 and may, altogether, be useful FTLD population. information in the context of diagnostics. In a nutshell, our results imply that a significantly higher Despite some previous conflicting reports of direct (or in- proportion of FTLD cases, with Nordic rather than verse) correlation between C9orf72 expansions and Mediterranean genetic ancestry, is likely to develop AAO,16,21,23 we (as others22,24) found a significant inverse bvFTD in presence of intermediate and long (pathogenic) correlation between C9orf72 expansion length and AAO. In expansions, whereas long (pathogenic) expansions are addition, and interestingly, our data also indicate that (almost) negligible in PPA, regardless of ancestry. Clearly, Central/Northern European genetic ancestry contributes to a multiple factors including genetic heterogeneity, epige- decreased AAO (independently from the expansions), netic changes, ethnicity, as well as environmental factors Neurology.org/N Neurology | Volume 95, Number 24 | December 15, 2020 e3295 and habits that may subsist within and across multicultural Ricerca Neurogenetica. B. Miller is supported by the NIH cohorts, all together, contribute to disease predisposition, (grants P50-AG023501 and P01-AG1972403) (BLM). C.M. onset, and progression.22,37,38 These concepts, reinforced Morris is supported by the Newcastle Brain Tissue Resource, by our study, warrant further characterization of genetic, the UK Medical Research Council (grant G0400074), the environmental, and additional clinical measures to fine- NIHR Newcastle Biomedical Research Centre awarded to tune models able to predict disease outcome to comple- the Newcastle upon Tyne NHS Foundation Trust and ment diagnostic criteria, and possibly assist in the identi- Newcastle University, and a grant from the Alzheimer’s fication of informative cohorts for tailored clinical trials Society and Alzheimer’s Research UK as part of the Brains and the development of effective personalized therapies. for Dementia Research Project. B. Nacmias and S.B. Sando are supported by the Ricerca di Ateneo 2019. E. Rogaeva is Acknowledgment supported by the Canadian Consortium on Neuro- The authors thank the patients and their families and the degeneration in Aging. B. Rogelj is supported by grants from IFGC (ifgcsite.wordpress.com/) phase III network. the Slovenian Research Agency (grants P4-0127, J3-8201, J3-9263). J. van Rooij is supported by the Wellcome Trust Study funding (grant 103838), by the Medical Research Council (grant R. Ferrari and B. Costa are supported by funding from the number SUAG004/91365), and by the National Institute for Alzheimer’s Society (grants 284 and 447). V. Alvarez and M. Health Research Cambridge Biomedical Research Centre Menendez-Gonzalez are supported by the Fondos Feder and Biomedical Research Unit in Dementia (NIHR, grant (grant PI 15/00878). O. Andreassen is supported by the RG64473). A. Rendina is supported by the Innovative Research Council of Norway (grant 223273), Norwegian Medicines Initiative 2 Joint Undertaking, which receives Health Association, and the KG Jebsen Stiftelsen. L. Benussi, support from the European Union’s Horizon 2020 research R. Ghidoni, G. Rossi, and F. Tagliavini are supported by the and innovation programme and EFPIA (grant 115975), by Italian Ministry of Health–Ricerca Corrente. G. Bråthen and Acción Estratégica en Salud integrated in the Spanish Na- R. Ghidoni are supported by the Italian Ministry of Health tional R + D + I Plan (grants PI13/02434 and PI16/01861), (grant RF-2016-02361492). D. Blackburn is supported by the by ISCIII (Instituto de Salud Carlos III) Subdirección Sheffield Biomedical Research Centre. L. Bernardi is sup- General de Evaluación, and by the Fondo Europeo de ported by the National Institute for Health Research Cam- Desarrollo Regional (FEDER-Una manera de Hacer Eu- bridge Biomedical Research Centre and Biomedical Research ropa). M. Boada and A. Ruiz are funded by Fundación Unit in Dementia (NIHR, grant RG64473). T.E. Cope is bancaria La Caixa and Grifols SA (GR@ACE project). R. supported by the Association of British Neurologists; the Sanchez-Valle is funded by the Spanish National Institute of recruitment and clinical characterization of research partici- Health Carlos III (ISCIII) under the aegis of the EU Joint pants at Washington University were supported by NIH Programme–Neurodegenerative Disease Research (JPND) (grants R01AG044546, RF1AG053303, R01AG058501, (grant AC14/00013) and Fundacio Marato de TV3 U01AG058922, P50 AG05681, P01 AG03991, and P01 (20143810) (RSV). J.Q. Trojanowski is supported by the AG026276). F. Frangipane is supported by ONLUS Lamezia NIH (grant AG09215). C. Van Broeckhoven and J. Van der Terme. C. Graff is supported by grants from JPND Prefrontals Zee are supported by the Flemish Government initiated Swedish Research Council (VR) 529-2014-7504, Swedish Impulse Program on Networks for Dementia Research Research Council (VR) 2015-02926, Swedish Research (VIND) and the Methusalem Excellence Program, by the Council (VR) 2018-02754, Swedish FTD Initiative-Schörling Research Foundation Flanders (FWO), and by the Univer- Foundation, Swedish Brain Foundation, Swedish Alzheimer sity of Antwerp Research Fund (Belgium). M.L. Waldö is Foundation, Stockholm County Council ALF, Karolinska supported by the Elly Berggren Foundation. J. Yokoyama is Institutet Doctoral Funding, and StratNeuro, Swedish funded by NIA K01 AG049152. Demensfonden. M. Gallo is supported by the NIH (grant AG054519). M. Gallucci, E. Scarpini, J.C. Thompson and Disclosure V.M. Van Deerlin are supported by the NIH (grant C. Cruchaga receives research support from Biogen, EISAI, AG017586, and P30 AG10124 and U01 AG062418). J. Hardy Alector, and Parabon. The funders of the study had no role in and P.A. Lewis are supported by an MRC Programme grant the collection, analysis, or interpretation of data, in the writing (MR/N026004/1). J. Hardy is supported by the UK De- of the report, or in the decision to submit the paper for mentia Research Institute, which receives its funding from publication. C. Cupidi is a member of the advisory board of DRI Ltd, funded by the UK Medical Research Council, Alz- ADx Healthcare and Vivid Genomics. B. Costa, C. Manzoni, heimer’s Society and Alzheimer’s Research UK, Wellcome M. Bernal-Quiros, D.A. Kia, M. Aguilar, I. Alvarez, V. Alvarez, Trust (award 202903/Z/16/Z), Dolby Family Fund, Na- O. Andreassen, M. Anfossi, S. Bagnoli, L. Benussi, L. Bernardi, tional Institute for Health Research University College Lon- G. Binetti, D. Blackburn, M. Boada, B. Borroni, L. Bowns, G. don Hospitals Biomedical Research Centre, BRCNIHR Bråthen, A.C. Bruni, H.-H. Chiang, J. Clarimon, S. Colville, Biomedical Research Centre at University College London M.E. Conidi, T.E. Cope, C. Cruchaga, M.E. Di Battista, J. Hospitals NHS Foundation Trust, and University College Diehl-Schmid, M. Diez-Fairen, O. Dols-Icardo, E. Durante, D. London. R. Maletta is supported by the Associazione per la Flisar, F. Frangipane, D. Galimberti, M. Gallo, M. Gallucci, R. e3296 Neurology | Volume 95, Number 24 | December 15, 2020 Neurology.org/N Ghidoni, C. Graff, J.H. Grafman, M. Grossman, J. Hardy, I. Hernández, G.J.T. Holloway, E.D. Huey, I. Illán-Gala, A. Appendix 1 (continued) Karydas, B. Khoshnood, M.G. Kramberger, M. Kristiansen, Name Location Contribution P.A. Lewis, A. Lleó, G.K. Madhan, R. Maletta, A. Maver, M. Menendez-Gonzalez, G. Milan, B. Miller, M.O. Mol, P. Maria Anfossi, Regional Neurogenetic Critical review of manuscript PhD Centre, ASPCZ, Lamezia for intellectual content, Momeni, S. Moreno-Grau, C.M. Morris, B. Nacmias, C. Terme, Italy contribution of samples and Nilsson, V. Novelli, L. Öijerstedt, A. Padovani, S. Pal, Y. demographics metadata Panchbhaya, P. Pastor, B. Peterlin, I. Piaceri, S. Pickering- Silvia Bagnoli, Department of Critical review of Brown, Y.A.L. Pijnenburg, A.A. Puca, I. Rainero, A. Rendina, PhD Neuroscience, manuscript for Psychology, Drug intellectual content, A.M.T. Richardson, E. Rogaeva, B. Rogelj, S. Rollinson, G. Research and Child contribution of samples Rossi, C. Rossmeier, J.B. Rowe, E. Rubino, A. Ruiz, R. Health, University of and demographics Florence, Italy metadata Sanchez-Valle, S.B. Sando, A.F. Santillo, J. Saxon, E. Scarpini, M. Serpente, N. Smirne, S. Sorbi, E. Suh, F. Tagliavini, J.C. Luisa Benussi, Molecular Markers Critical review of PhD Laboratory, IRCCS Istituto manuscript for Thompson, J.Q. Trojanowski, V.M. Van Deerlin, J. Van der Centro San Giovanni di intellectual content, Zee, C. Van Broeckhoven, J. van Rooij, J.C. Van Swieten, A. Dio Fatebenefratelli, contribution of samples Veronesi, E. Vitale, M.L. Waldö, C. Woodward, J. Yokoyama, Brescia, Italy and demographics metadata V. Escott-Price, J.M. Polke, and R. Ferrari report no disclo- sures relevant to the manuscript. Go to Neurology.org/N for Livia Regional Neurogenetic Critical review of Bernardi, PhD Centre, ASPCZ, Lamezia manuscript for full disclosures. Terme, Italy intellectual content, contribution of samples and demographics metadata Publication history Received by Neurology April 15, 2020. Accepted in final form Giuliano Molecular Markers Critical review of Binetti, MD Laboratory, IRCCS Istituto manuscript for August 12, 2020. Centro San Giovanni di intellectual content, Dio Fatebenefratelli, contribution of samples Brescia, Italy and demographics Appendix 1 Authors metadata Name Location Contribution Daniel J. Sheffield Institute for Critical review of Blackburn, Translational manuscript for Beatrice University College C9orf72 expansions MD, PhD Neuroscience (SITraN), intellectual content, Costa, BSc London, Institute of screening, data Department of contribution of samples Neurology, UK interpretation and Neuroscience, University and demographics drafting of manuscript of Sheffield, metadata UK Claudia School of Pharmacy, Project design, data Manzoni, PhD University College analyses and Mercè Boada, Research Center and Critical review of London, UK interpretation, MD, PhD Memory Clinic, Fundació manuscript for manuscript drafting ACE, Institut Català de intellectual content, Neurociències Aplicades, contribution of samples Manuel Neurogenetics C9orf72 expansions Universitat Internacional and demographics Bernal- Laboratory, National screening, data de Catalunya (UIC), metadata Quiros, PhD Hospital for Neurology interpretation and Barcelona, Spain and Neurosurgery, drafting of manuscript London, UK Barbara Centre for Critical review of Borroni, MD Neurodegenerative manuscript for Demis A. Kia, University College Data interpretation and Disorders, Department of intellectual content, MD London, Institute of drafting of manuscript Clinical and Experimental contribution of samples Neurology, UK Sciences, University of and demographics Brescia, Italy metadata Miquel Aptima Clinic, Terrassa, Critical review of manuscript Aguilar, MD Barcelona, Spain for intellectual content, Lucy Bowns Department of Clinical Critical review of contribution of samples and Neurosciences, manuscript for demographics metadata Cambridge University, UK intellectual content, contribution of samples Ignacio Memory Disorders Unit, Critical review of manuscript and demographics Alvarez, MSc Department of Neurology, for intellectual content, metadata University Hospital Mutua de contribution of samples and Terrassa, Barcelona, Spain demographics metadata Geir Bråthen, Department of Critical review of MD, PhD Neurology, University manuscript for Victoria Hospital Universitario Critical review of manuscript Hospital of Trondheim, intellectual content, Alvarez, PhD Central de Asturias, for intellectual content, Norway contribution of samples Oviedo, Asturias, Spain contribution of samples and and demographics demographics metadata metadata Ole A. NORMENT, Institute of Critical review of Amalia C. Regional Neurogenetic Critical review of Andreassen, Clinical Medicine, manuscript for Bruni, MD Centre, ASPCZ, Lamezia manuscript for MD, PhD University of Oslo, intellectual content, Terme, Italy intellectual content, Norway contribution of samples contribution of samples and demographics and demographics metadata metadata Continued Neurology.org/N Neurology | Volume 95, Number 24 | December 15, 2020 e3297 Appendix 1 (continued) Appendix 1 (continued) Name Location Contribution Name Location Contribution Huei-Hsin Karolinska Institutet, Dept Critical review of Elisabetta Immunohematology and Critical review of Chiang, PhD NVS, Division of manuscript for Durante, PhD Transfusional Medicine manuscript for Neurogeriatrics, intellectual content, Service, Local Health intellectual content, Bioclinicum, Solna, contribution of samples Authority n.2 Marca contribution of samples Sweden and demographics Trevigiana, Treviso, Italy and demographics metadata metadata Jordi Department of Critical review of Dušan Flisar, Department of Critical review of manuscript Clarimon, PhD Neurology, IIB Sant Pau, manuscript for MD Neurology, University for intellectual content, Hospital de la Santa Creu i intellectual content, Medical Center Ljubljana, contribution of samples and Sant Pau, Universitat contribution of samples Slovenia demographics metadata Autònoma de Barcelona, and demographics Spain metadata Francesca Regional Neurogenetic Critical review of manuscript Frangipane, Centre, ASPCZ, Lamezia for intellectual content, Shuna Anne Rowling Critical review of MD Terme, Italy contribution of samples and Colville, MSc Regenerative Neurology manuscript for demographics metadata Clinic, University of intellectual content, Edinburgh, UK contribution of samples Daniela University of Milan, Dino Critical review of manuscript and demographics Galimberti, Ferrari Center, Italy for intellectual content, metadata PhD contribution of samples and demographics metadata Maria E. Regional Neurogenetic Critical review of Conidi, PhD Centre, ASPCZ, Lamezia manuscript for Maura Gallo, Regional Neurogenetic Critical review of Terme, Italy intellectual content, PhD Centre, ASPCZ, Lamezia manuscript for intellectual contribution of samples Terme, Italy content, contribution of and demographics samples and metadata demographics metadata Tom E. Cope, Department of Clinical Critical review of Maurizio Cognitive Impairment Critical review of MD, PhD Neurosciences, manuscript for Gallucci, MD Center, Local Health manuscript for Cambridge University, UK intellectual content, Authority n.2 Marca intellectual content, contribution of samples Trevigiana, Treviso, Italy contribution of samples and demographics and demographics metadata metadata Carlos NeuroGenomics and Critical review of Roberta Molecular Markers Critical review of Cruchaga, Informatics, Washington manuscript for Ghidoni, PhD Laboratory, IRCCS Istituto manuscript for PhD University, Department of intellectual content Centro San Giovanni di intellectual content, Psychiatry, St. Louis, MO Dio Fatebenefratelli, contribution of samples Brescia, Italy and demographics Chiara Cupidi, Regional Neurogenetic Critical review of metadata MD Centre, ASPCZ, Lamezia manuscript for Terme, Italy intellectual content, Caroline Karolinska Institutet, Dept Critical review of contribution of samples Graff, MD, NVS, Division of manuscript for and demographics PhD Neurogeriatrics, intellectual content, metadata Bioclinicum, Solna, contribution of samples Sweden and demographics Maria Elena Di Cognitive Impairment Critical review of metadata Battista, MD, Center, Local Health manuscript for PhD Authority n.2 Marca intellectual content, Jordan H. Cognitive Neuroscience Critical review of Trevigiana, Treviso, Italy contribution of samples Grafman, PhD Lab, Think and Speak Lab, manuscript for and demographics Shirley Ryan AbilityLab, intellectual content, metadata Chicago, IL contribution of samples and demographics Janine Diehl- Technical University of Critical review of metadata Schmid, MD Munich, School of manuscript for Medicine, Department of intellectual content, Murray Department of Critical review of Psychiatry and contribution of samples Grossman, Neurology, Perelman manuscript for Psychotherapy, Germany and demographics MD School of Medicine at the intellectual content, metadata University of contribution of samples Pennsylvania, and demographics Monica Diez- Memory Disorders Unit, Critical review of Philadelphia metadata Fairen, MSc Department of manuscript for Neurology, University intellectual content, John Hardy, UCL Dementia Research Critical review of Hospital Mutua de contribution of samples PhD Institute Wing 1.2 manuscript for Terrassa, Barcelona, and demographics Cruciform Building, intellectual content Spain metadata London, UK Oriol Dols- Department of Critical review of Isabel Research Center and Critical review of Icardo, PhD Neurology, IIB Sant Pau, manuscript for Hernández, Memory Clinic. Fundació manuscript for Hospital de la Santa Creu i intellectual content, MD, PhD ACE, Institut Català de intellectual content, Sant Pau, Universitat contribution of samples Neurociències Aplicades, contribution of samples Autònoma de Barcelona, and demographics Universitat Internacional and demographics Barcelona, metadata de Catalunya (UIC), metadata Spain Barcelona, Spain e3298 Neurology | Volume 95, Number 24 | December 15, 2020 Neurology.org/N Appendix 1 (continued) Appendix 1 (continued) Name Location Contribution Name Location Contribution Guy J.T. Royal Edinburgh Hospital, Critical review of manuscript Manuel Hospital Universitario Critical review of Holloway, Edinburgh, UK for intellectual content, Menendez- Central de Asturias, manuscript for MBBS, contribution of samples and Gonzalez, MD, Oviedo, Asturias, Spain intellectual content, MRCPsych demographics metadata PhD contribution of samples and demographics Edward D. Taub Institute for Critical review of metadata Huey, MD Research on Alzheimer’s manuscript for Disease and the Aging intellectual content, Graziella Geriatric Center Frullone Critical review of Brain, Columbia contribution of samples Milan, MD ASL Napoli 1 Centro, manuscript for University, New York, NY and demographics Napoli, Italy intellectual content, metadata contribution of samples and demographics Ignacio Illán- Department of Critical review of metadata Gala, MD, PhD Neurology, IIB Sant Pau, manuscript for Hospital de la Santa Creu i intellectual content, Bruce L. Department of Critical review of Sant Pau, Universitat contribution of samples Miller, MD Neurology, Memory and manuscript for Autònoma de Barcelona, and demographics Aging Center, University intellectual content, Spain metadata of California, San contribution of samples Francisco and demographics Anna Karydas, Department of Critical review of metadata MSc Neurology, Memory and manuscript for Aging Center, University intellectual content, Merel O. Mol, Department of Critical review of of California, San contribution of samples MSc Neurology, Erasmus manuscript for Francisco and demographics Medical Center, intellectual content, metadata Rotterdam, the contribution of samples Netherlands and demographics Behzad Karolinska Institutet, Dept Critical review of metadata Khoshnood, NVS, Division of manuscript for PhD Neurogeriatrics, intellectual content, Parastoo Rona Holdings, Silicon Critical review of Bioclinicum, Solna, contribution of samples Momeni, PhD Valley, CA manuscript for Sweden and demographics intellectual content, metadata contribution of metadata Milica G. Department of Critical review of Sonia Moreno- Research Center and Critical review of Kramberger, Neurology, University manuscript for Grau, PhD Memory Clinic, Fundació manuscript for MD, PhD Medical Center Ljubljana, intellectual content, ACE, Institut Català de intellectual content, Slovenia contribution of samples Neurociències Aplicades, contribution of samples and demographics Universitat Internacional and demographics metadata de Catalunya (UIC), metadata Barcelona, Spain Mark UCL Genomics, UCL Great Critical review of Kristiansen, Ormond Street Institute of manuscript for Christopher Newcastle Brain Tissue Critical review of PhD Child Health, London, UK intellectual content M. Morris, Resource, Institute of manuscript for PhD Neuroscience, Newcastle intellectual content, Patrick A. The Royal Veterinary Critical review of University, Edwardson contribution of samples Lewis, PhD College, Department of manuscript for Building, Campus for and demographics Comparative Biomedical intellectual content Ageing and Vitality, metadata Sciences, London, UK Newcastle upon Tyne, UK Alberto Lleó, Department of Critical review of Benedetta Department of Critical review of MD, PhD Neurology, IIB Sant Pau, manuscript for Nacmias, PhD Neuroscience, manuscript for Hospital de la Santa Creu i intellectual content, Psychology, Drug intellectual content, Sant Pau, Universitat contribution of samples Research and Child contribution of samples Autònoma de Barcelona, and demographics Health, University of and demographics Spain metadata Florence, Italy metadata Gaganjit K. UCL Genomics, UCL Great Critical review of Christer Department of Critical review of Madhan, MSc Ormond Street Institute of manuscript for Nilsson, MD Neurology, Skåne manuscript for Child Health, London, UK intellectual content, University Hospital, intellectual content, contribution of samples Malmö, Sweden contribution of samples and demographics and demographics metadata metadata Raffaele Regional Neurogenetic Critical review of Valeria Fondazione Policlinico Critical review of Maletta, MD Centre, ASPCZ, Lamezia manuscript for Novelli, PhD Universitario A. Gemelli manuscript for Terme, Italy intellectual content, IRCCS, Rome, Italy intellectual content, contribution of samples contribution of samples and demographics and demographics metadata metadata Aleš Maver, Clinical Institute of Critical review of Linn Karolinska Institutet, Dept Critical review of MD, PhD Medical Genetics, manuscript for Öijerstedt, NVS, Division of manuscript for University Medical Center intellectual content, MD Neurogeriatrics, intellectual content, Ljubljana, Slovenia contribution of samples Bioclinicum, Solna, contribution of samples and demographics Sweden and demographics metadata metadata Continued Neurology.org/N Neurology | Volume 95, Number 24 | December 15, 2020 e3299 Appendix 1 (continued) Appendix 1 (continued) Name Location Contribution Name Location Contribution Alessandro Centre for Critical review of Anna M.T. Manchester Centre for Critical review of Padovani, MD Neurodegenerative manuscript for Richardson, Clinical Neurosciences, manuscript for Disorders, Department of intellectual content, FRCP Salford Royal NHS Trust, intellectual content, Clinical and Experimental contribution of samples Manchester, UK contribution of samples Sciences, University of and demographics and demographics Brescia, Italy metadata metadata Suvankar Pal, Anne Rowling Critical review of Ekaterina Tanz Centre for Critical review of MBBS, MRCP, Regenerative Neurology manuscript for Rogaeva, PhD Research in manuscript for MD Clinic, University of intellectual content, Neurodegenerative intellectual content Edinburgh, UK contribution of samples Diseases, University and demographics of Toronto, metadata Canada Yasmin UCL Genomics, UCL Great Critical review of Boris Rogelj, Department of Critical review of manuscript Panchbhaya, Ormond Street Institute of manuscript for PhD Biotechnology, Jožef for intellectual content, MSc Child Health, London, UK intellectual content Stefan Institute, Ljubljana, contribution of samples and Slovenia demographics metadata Pau Pastor, Memory Disorders Unit, Critical review of MD, PhD Department of manuscript for Sara Division of Neuroscience Critical review of Neurology, University intellectual content, Rollinson, & Experimental manuscript for Hospital Mutua de contribution of samples PhD Psychology, The intellectual content, Terrassa, Barcelona, and demographics University of Manchester, contribution of samples Spain metadata UK and demographics metadata Borut Clinical Institute of Critical review of Peterlin, MD, Medical Genetics, manuscript for Giacomina Division of Neurology V Critical review of PhD University Medical Center intellectual content, Rossi, PhD and Neuropathology; manuscript for Ljubljana, Slovenia contribution of samples Fondazione IRCCS Istituto intellectual content, and demographics Neurologico Carlo Besta, contribution of samples metadata Milan, Italy and demographics metadata Irene Piaceri, Department of Critical review of PhD Neuroscience, manuscript for Carola Technical University of Critical review of Psychology, Drug intellectual content, Roßmeier, MD Munich, School of manuscript for Research and Child contribution of Medicine, Department of intellectual content, Health, University of samples and Psychiatry and contribution of samples Florence, Italy demographics Psychotherapy, Germany and demographics metadata metadata Stuart Division of Neuroscience Critical review of James B. Department of Clinical Critical review of Pickering- & Experimental manuscript for Rowe, MD, Neurosciences, manuscript for Brown, PhD Psychology, The intellectual content, PhD Cambridge University, UK intellectual content, University of Manchester, contribution of samples contribution of samples UK and demographics and demographics metadata metadata Yolande A.L. Amsterdam University Critical review of Elisa Rubino, Neurology I, Department Critical review of Pijnenburg, Medical Center, VU manuscript for MD, PhD of Neuroscience, manuscript for MD, PhD University Medical Center, intellectual content, University of Torino, Italy intellectual content, the Netherlands contribution of contribution of samples samples and and demographics demographics metadata metadata Agustı́n Ruiz, Research Center and Critical review of Annibale A. Cardiovascular Research Critical review of MD, PhD Memory Clinic. Fundació manuscript for Puca, MD Unit, IRCCS Multimedica, manuscript for ACE, Institut Català de intellectual content, Milan, Italy intellectual content, Neurociències Aplicades, contribution of samples contribution of samples Universitat Internacional and demographics and demographics de Catalunya (UIC), metadata metadata Barcelona, Spain Innocenzo Neurology I, Department Critical review of Raquel Alzheimer’s Disease and Critical review of Rainero, MD, of Neuroscience, manuscript for Sanchez-Valle, Other Cognitive Disorders manuscript for PhD University of Torino, Italy intellectual content, MD, PhD Unit, Hospital Clı́nic of intellectual content, contribution of samples Barcelona, Spain contribution of samples and demographics and demographics metadata metadata Antonella NeurOMICS laboratory, Critical review of Sigrid B. Department of Critical review of Rendina, PhD Institute of Biochemistry manuscript for Sando, PhD Neurology, University manuscript for and Cell Biology (IBBC), intellectual content, Hospital of Trondheim, intellectual content, CNR Napoli, Italy contribution of samples Norway contribution of samples and demographics and demographics metadata metadata e3300 Neurology | Volume 95, Number 24 | December 15, 2020 Neurology.org/N Appendix 1 (continued) Appendix 1 (continued) Name Location Contribution Name Location Contribution Alexander F. Clinical Memory Research Critical review of Julie van der Neurodegenerative Brain Critical review of Santillo, MD, Unit, Lund University, manuscript for Zee, PhD Diseases group, Center manuscript for intellectual PhD Sweden intellectual content, for Molecular Neurology, content, contribution of contribution of samples VIB, Antwerp, Belgium samples and demographics and demographics metadata metadata Christine Van Neurodegenerative Brain Critical review of manuscript Jennifer Manchester Centre for Critical review of Broeckhoven, Diseases group, Center for intellectual content, Saxon, MSc Clinical Neurosciences, manuscript for DSc, PhD for Molecular Neurology, contribution of samples and Salford Royal NHS Trust, intellectual content, VIB, Antwerp, Belgium demographics metadata UK contribution of samples and demographics Jeroen G.J. van Department of Critical review of metadata Rooij Neurology, Erasmus manuscript for Medical Center, intellectual content, Elio Scarpini, University of Milan, Dino Critical review of manuscript Rotterdam, the contribution of samples MD Ferrari Center, Italy for intellectual content, Netherlands and demographics contribution of samples and metadata demographics metadata John C. van Department of Critical review of Maria University of Milan, Dino Critical review of Swieten, MD, Neurology, Erasmus manuscript for intellectual Serpente, PhD Ferrari Center, Italy manuscript for PhD Medical Center, content, contribution of intellectual content, Rotterdam, the samples and demographics contribution of samples Netherlands metadata and demographics metadata Arianna Cognitive Impairment Critical review of Veronesi, MD, Center, Local Health manuscript for Nicoletta Regional Neurogenetic Critical review of PhD Authority n.2 Marca intellectual content, Smirne, BSc Centre, ASPCZ, Lamezia manuscript for Trevigiana, Treviso, contribution of samples Terme, Italy intellectual content, Italy and demographics contribution of samples metadata and demographics metadata Emilia Vitale, NeurOMICS laboratory, Critical review of PhD Institute of Biochemistry manuscript for intellectual Sandro Sorbi, Department of Critical review of and Cell Biology (IBBC), content, contribution of MD Neuroscience, manuscript for CNR Napoli, Italy samples and demographics Psychology, Drug intellectual content, metadata Research and Child contribution of samples Health, University of and demographics Maria L. Division of Clinical Critical review of Florence, Italy metadata Waldö, MD, Sciences Helsingborg, manuscript for PhD Department of Clinical intellectual content, EunRan Suh, Department of Pathology Critical review of Sciences Lund, Lund contribution of samples PhD and Laboratory Medicine, manuscript for University, Sweden and demographics Perelman School of intellectual content, metadata Medicine at the University contribution of of Pennsylvania, samples and Cathy Neurogenetics C9orf72 expansions Philadelphia demographics Woodward, Laboratory, National screening, data metadata MSc Hospital for Neurology interpretation and and Neurosurgery, drafting of Fabrizio Fondazione IRCCS Istituto Critical review of London, UK manuscript Tagliavini, MD Neurologico Carlo Besta, manuscript for Milan, Italy intellectual content, Jennifer S. Department of Critical review of contribution of Yokoyama, Neurology, Memory and manuscript for intellectual samples and PhD Aging Center, University content, contribution of demographics of California, San samples and demographics metadata Francisco metadata Jennifer C. Manchester Centre for Critical review of Valentina Medical Research Council Project design, data Thompson, Clinical Neurosciences, manuscript for intellectual Escott-Price, Centre for Neuropsychiatric analyses and PhD Salford Royal NHS Trust, content, contribution of PhD Genetics and Genomics, interpretation, Manchester, UK samples and demographics Division of Psychological manuscript drafting metadata Medicine and Clinical Neurosciences, Cardiff John Q. Department of Pathology Critical review of University, UK and Dementia Trojanowski, and Laboratory Medicine, manuscript for Research Institute, Cardiff MD, PhD Perelman School of intellectual content, University, UK Medicine at the University contribution of of Pennsylvania, samples and James M. Neurogenetics Laboratory, C9orf72 expansions Philadelphia demographics Polke, PhD National Hospital for screening, data metadata Neurology and interpretation and Neurosurgery, London, UK drafting of manuscript Vivianna M. Department of Pathology Critical review of Van Deerlin, and Laboratory Medicine, manuscript for intellectual Raffaele Department of Project design, data MD, PhD Perelman School of content, contribution of Ferrari, PhD Neurodegenerative analyses and Medicine at the University samples and demographics Disease, University interpretation, of Pennsylvania, metadata College London, Institute manuscript drafting Philadelphia of Neurology, UK Neurology.org/N Neurology | Volume 95, Number 24 | December 15, 2020 e3301 19. Xi Z, van Blitterswijk M, Zhang M, et al. Jump from pre-mutation to pathologic expansion in C9orf72. Am J Hum Genet 2015;96:962–970. Appendix 2 Coinvestigators 20. Van Mossevelde S, Engelborghs S, van der Zee J, Van Broeckhoven C. Genotype- Coinvestigators are listed at links.lww.com/WNL/B240 phenotype links in frontotemporal lobar degeneration. Nat Rev Neurol 2018;14: 363–378. 21. Fournier C, Barbier M, Camuzat A, et al. Relations between C9orf72 expansion size in blood, age at onset, age at collection and transmission across generations in patients and presymptomatic carriers. Neurobiol Aging 2019;74:234.e231–234.e238. References 22. Gijselinck I, Van Mossevelde S, van der Zee J, et al. The C9orf72 repeat size correlates 1. Ratnavalli E, Brayne C, Dawson K, Hodges JR. The prevalence of frontotemporal with onset age of disease, DNA methylation and transcriptional downregulation of the dementia. Neurology 2002;58:1615–1621. promoter. Mol Psychiatry 2016;21:1112–1124. 2. Neary D, Snowden JS, Gustafson L, et al. Frontotemporal lobar degeneration: a 23. van Blitterswijk M, DeJesus-Hernandez M, Niemantsverdriet E, et al. Association consensus on clinical diagnostic criteria. Neurology 1998;51:1546–1554. between repeat sizes and clinical and pathological characteristics in carriers of 3. Gorno-Tempini ML, Hillis AE, Weintraub S, et al. Classification of primary pro- C9ORF72 repeat expansions (Xpansize-72): a cross-sectional cohort study. Lancet gressive aphasia and its variants. Neurology 2011;76:1006–1014. 4. Strong MJ, Abrahams S, Goldstein LH, et al. Amyotrophic lateral sclerosis– Neurol 2013;12:978–988. frontotemporal spectrum disorder (ALS-FTSD): revised diagnostic criteria. Amyo- 24. Van Mossevelde S, van der Zee J, Gijselinck I, et al. Clinical evidence of disease anticipation troph Lateral Scler Frontotemporal Degener 2017;18:153–174. in families segregating a C9orf72 repeat expansion. JAMA Neurol 2017;74:445–452. 5. Babić Leko M, Zupunski V, Kirincich J, et al. Molecular mechanisms of neuro- 25. Rascovsky K, Hodges JR, Knopman D, et al. Sensitivity of revised diagnostic degeneration related to C9orf72 hexanucleotide repeat expansion. Behav Neurol criteria for the behavioural variant of frontotemporal dementia. Brain 2011;134: 2019;2019:2909168. 2456–2477. 6. DeJesus-Hernandez M, Mackenzie IR, Boeve BF, et al. Expanded GGGGCC hex- 26. Blauwendraat C, Faghri F, Pihlstrom L, et al. NeuroChip, an updated version of the anucleotide repeat in noncoding region of C9ORF72 causes chromosome 9p-linked NeuroX genotyping platform to rapidly screen for variants associated with neuro- FTD and ALS. Neuron 2011;72:245–256. logical diseases. Neurobiol Aging 2017;57:247 e249–247 e213. 7. Ferrari R, Manzoni C, Hardy J. Genetics and molecular mechanisms of frontotemporal 27. Ferrari R, Mok K, Moreno JH, et al. Screening for C9ORF72 repeat expansion in lobar degeneration: an update and future avenues. Neurobiol Aging 2019;78:98–110. FTLD. Neurobiol Aging 2012;33:1850.e1–e11. 8. Pottier C, Ravenscroft TA, Sanchez-Contreras M, Rademakers R. Genetics of FTLD: 28. Renton AE, Majounie E, Waite A, et al. A hexanucleotide repeat expansion in overview and what else we can expect from genetic studies. J Neurochem 2016; C9ORF72 is the cause of chromosome 9p21-linked ALS-FTD. Neuron 2011;72: 138(suppl 1):32–53. 257–268. 9. Seelaar H, Rohrer JD, Pijnenburg YA, Fox NC, van Swieten JC. Clinical, genetic and 29. Laaksovirta H, Peuralinna T, Schymick JC, et al. Chromosome 9p21 in amyotrophic pathological heterogeneity of frontotemporal dementia: a review. J Neurol Neurosurg lateral sclerosis in Finland: a genome-wide association study. Lancet Neurol 2010;9: Psychiatry 2011;82:476–486. 978–985. 10. van der Zee J, Gijselinck I, Dillen L, et al. A Pan-European study of the C9orf72 repeat 30. Benussi L, Rossi G, Glionna M, et al. C9ORF72 hexanucleotide repeat number in associated with FTLD: geographic prevalence, genomic instability, and intermediate frontotemporal lobar degeneration: a genotype-phenotype correlation study. repeats. Hum Mutat 2013;34:363–373. J Alzheimers Dis 2015;45:319. 11. LT T. The genetics of monogenic frontotemporal dementia. Dement Neuropsychol 31. Devenney E, Bartley L, Hoon C, et al. Progression in behavioral variant fronto- 2015:219–229. temporal dementia: a longitudinal study. JAMA Neurol 2015;72:1501–1509. 12. Turner MR, Al-Chalabi A, Chio A, et al. Genetic screening in sporadic ALS and FTD. 32. Galimberti D, Fenoglio C, Serpente M, et al. Autosomal dominant frontotemporal J Neurol Neurosurg Psychiatry 2017;88:1042–1044. lobar degeneration due to the C9ORF72 hexanucleotide repeat expansion: late-onset 13. Majounie E, Renton AE, Mok K, et al. Frequency of the C9orf72 hexanucleotide psychotic clinical presentation. Biol Psychiatry 2013;74:384–391. repeat expansion in patients with amyotrophic lateral sclerosis and frontotemporal 33. Ramos EM, Dokuru DR, Van Berlo V, et al. Genetic screen in a large series of patients dementia: a cross-sectional study. Lancet Neurol 2012;11:323–330. 14. Ramos EM, Koros C, Dokuru DR, et al. Frontotemporal dementia spectrum: first with primary progressive aphasia. Alzheimers Dement 2019;15:553–560. genetic screen in a Greek cohort. Neurobiol Aging 2019;75:224.e221–224.e228. 34. Simon-Sanchez J, Dopper EG, Cohn-Hokke PE, et al. The clinical and pathological 15. Mok K, Traynor BJ, Schymick J, et al. Chromosome 9 ALS and FTD locus is probably phenotype of C9ORF72 hexanucleotide repeat expansions. Brain 2012;135:723–735. derived from a single founder. Neurobiol Aging 2012;33:209.e203–209.e208. 35. Ralph P, Coop G. The geography of recent genetic ancestry across Europe. PLoS Biol 16. Beck J, Poulter M, Hensman D, et al. Large C9orf72 hexanucleotide repeat expansions 2013;11:e1001555. are seen in multiple neurodegenerative syndromes and are more frequent than 36. Warby SC, Montpetit A, Hayden AR, et al. CAG expansion in the Huntington disease expected in the UK population. Am J Hum Genet 2013;92:345–353. gene is associated with a specific and targetable predisposing haplogroup. Am J Hum 17. Chiang HH, Forsell C, Lindstrom AK, et al. No common founder for C9orf72 Genet 2009;84:351–366. expansion mutation in Sweden. J Hum Genet 2017;62:321–324. 37. Huang T, Shu Y, Cai YD. Genetic differences among ethnic groups. BMC Genomics 18. Fratta P, Polke JM, Newcombe J, et al. Screening a UK amyotrophic lateral sclerosis 2015;16:1093. cohort provides evidence of multiple origins of the C9orf72 expansion. Neurobiol 38. Zhang M, Ferrari R, Tartaglia MC, et al. A C6orf10/LOC101929163 locus is asso- Aging 2015;36:546 e541–547. ciated with age of onset in C9orf72 carriers. Brain 2018;141:2895–2907. e3302 Neurology | Volume 95, Number 24 | December 15, 2020 Neurology.org/N