• David Pellerin, Matt C Danzi, Carlo Wilke, Mathilde Renaud, Sarah Fazal, Marie-Josée Dicaire, Carolin K Scriba, Catherine Ashton, Christopher Yanick, Danique Beijer, Adriana Rebelo, Clarissa Rocca, Zane Jaunmuktane, Joshua A Sonnen, Roxanne Larivière, David Genís, Laura Molina Porcel, Karine Choquet, Rawan Sakalla, Sylvie Provost, Rebecca Robertson, Xavier Allard-Chamard, Martine Tétreault, Sarah J Reiling, Sara Nagy, Vikas Nishadham, Meera Purushottam, Seena Vengalil, Mainak Bardhan, Atchayaram Nalini, Zhongbo Chen, Jean Mathieu, Rami Massie, Colin H Chalk, Anne-Louise Lafontaine, François Evoy, Marie-France Rioux, Jiannis Ragoussis, Kym M Boycott, Marie-Pierre Dubé, Antoine Duquette, Henry Houlden, Gianina Ravenscroft, Nigel G Laing, Phillipa J Lamont, Mario A Saporta, Rebecca Schüle, Ludger Schöls, Roberta La Piana, Matthis Synofzik, Stephan Zuchner, and Bernard Brais.
• From the Departments of Neurology and Neurosurgery (D.P., M.-J.D., J.A.S., R.L., R. Sakalla, R.R., X.A.-C., R.M., C.H.C., A.-L.L., R.L.P., B.B.) and Pathology (J.A.S.), Montreal Neurological Hospital and Institute, McGill Genome Centre, Department of Human Genetics (S.J.R., J.R.), and the Departments of Diagnostic Radiology (R.L.P.) and Human Genetics (K.C., R.R., X.A.-C., B.B.), McGill University, Montreal Heart Institute (S.P., M.-P.D.), the Departments of Neurosciences (M.T., A.D.) and Medicine (M.P.D.), Faculty of Medicine, Université de Montréal, Université de Montréal Beaulieu-Saucier Pharmacogenomics Center (S.P.), Centre de Recherche du Centre Hospitalier de l'Université de Montréal (M.T., A.D.), and Centre de Réadaptation Lucie-Bruneau (A.D., B.B.), Montreal, the Faculty of Medicine and Health Sciences, Sherbrooke University, Sherbrooke, QC (J.M., F.E., M.-F.R.), and Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa (K.M.B.) - all in Canada; the Department of Neuromuscular Disease, UCL Queen Square Institute of Neurology and the National Hospital for Neurology and Neurosurgery (D.P., C.R., S.N., H.H.), the Department of Clinical and Movement Neurosciences and Queen Square Brain Bank for Neurological Disorders (Z.J.) and the Department of Neurodegenerative Disease (Z.C.), UCL Queen Square Institute of Neurology, University College London, and the Division of Neuropathology, National Hospital for Neurology and Neurosurgery, University College London NHS Foundation Trust (Z.J.) - all in London; Dr. John T. Macdonald Foundation Department of Human Genetics and John P. Hussman Institute for Human Genomics (M.C.D., S.F., C.Y., D.B., A.R., S.Z.), and the Department of Neurology (C.Y., M.A.S.), University of Miami Miller School of Medicine, Miami; the Department of Neurodegenerative Diseases, Hertie Institute for Clinical Brain Research and Center of Neurology, University of Tübingen, and the German Center for Neurodegenerative Diseases - both in Tübingen, Germany (C.W., R. Schüle, L.S., M.S.); Service de Génétique Clinique et de Neurologie, Hôpital Brabois Enfants, and INSERM Unité 1256 N-GERE (Nutrition-Genetics and Environmental Risk Exposure), Université de Lorraine - both in Nancy, France (M.R.); Centre for Medical Research, University of Western Australia and Harry Perkins Institute of Medical Research (C.K.S., G.R., N.G.L.), the Department of Diagnostic Genomics, PathWest Laboratory Medicine, West Australian Department of Health (C.K.S.), and the Department of Neurology, Royal Perth Hospital (C.A., P.J.L.) - all in Perth, WA, Australia; the Ataxia and Hereditary Spastic Paraplegia Unit, Service of Neurology, Hospital Universitari de Girona Dr. Josep Trueta and Hospital Santa Caterina IAS, Girona (D.G.), and the Alzheimer's Disease and other Cognitive Disorders Unit, Service of Neurology, Hospital Clínic, Institut d'Investigacions Biomediques August Pi i Sunyer (IDIBAPS), University of Barcelona, and the Neurologic Tissue Brain Bank, Biobanc-Hospital Clínic-IDIBAPS, Barcelona (L.M.P.) - all in Spain; the Department of Genetics, Harvard Medical School, Boston (K.C.); the Department of Neurology, University Hospital Basel, University of Basel, Basel, Switzerland (S.N.); and the Department of Neurology (V.N., S.V., M.B., A.N.) and the Molecular Genetics Laboratory, Department of Psychiatry (M.P.), National Institute of Mental Health and Neurosciences, Bengaluru, India.
• N. Engl. J. Med. 2023 Jan 12; 388 (2): 128141128-141.

BackgroundThe late-onset cerebellar ataxias (LOCAs) have largely resisted molecular diagnosis.MethodsWe sequenced the genomes of six persons with autosomal dominant LOCA who were members of three French Canadian families and identified a candidate pathogenic repeat expansion. We then tested for association between the repeat expansion and disease in two independent case-control series - one French Canadian (66 patients and 209 controls) and the other German (228 patients and 199 controls). We also genotyped the repeat in 20 Australian and 31 Indian index patients. We assayed gene and protein expression in two postmortem cerebellum specimens and two induced pluripotent stem-cell (iPSC)-derived motor-neuron cell lines.ResultsIn the six French Canadian patients, we identified a GAA repeat expansion deep in the first intron of FGF14, which encodes fibroblast growth factor 14. Cosegregation of the repeat expansion with disease in the families supported a pathogenic threshold of at least 250 GAA repeats ([GAA]≥250). There was significant association between FGF14 (GAA)≥250 expansions and LOCA in the French Canadian series (odds ratio, 105.60; 95% confidence interval [CI], 31.09 to 334.20; P<0.001) and in the German series (odds ratio, 8.76; 95% CI, 3.45 to 20.84; P<0.001). The repeat expansion was present in 61%, 18%, 15%, and 10% of French Canadian, German, Australian, and Indian index patients, respectively. In total, we identified 128 patients with LOCA who carried an FGF14 (GAA)≥250 expansion. Postmortem cerebellum specimens and iPSC-derived motor neurons from patients showed reduced expression of FGF14 RNA and protein.ConclusionsA dominantly inherited deep intronic GAA repeat expansion in FGF14 was found to be associated with LOCA. (Funded by Fondation Groupe Monaco and others.).Copyright © 2022 Massachusetts Medical Society.

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