학술논문
GR.2 A deep intronic FGF14 GAA repeat expansion causes late-onset cerebellar ataxia
Document Type
Article
Author
Pellerin, D; Danzi, MC; Wilke, C; Renaud, M; Fazal, S; Dicaire, M; Scriba, CK; Ashton, C; Yanick, C; Beijer, D; Rebelo, A; Rocca, C; Jaunmuktane, Z; Sonnen, JA; Larivière, R; Genis, D; Porcel, L; Choquet, K; Sakalla, R; Provost, S; Tétreault, M; Reiling, SJ; Nagy, S; Nishadham, V; Purushottam, M; Vengalil, S; Bardhan, M; Nalini, A; Chen, Z; Mathieu, J; Massie, R; Chalk, CH; Lafontaine, A; Evoy, F; Rioux, M; Ragoussis, J; Boycott, KM; Dubé, M; Duquette, A; Houlden, H; Ravenscroft, G; Laing, NG; Lamont, P; Saporta, MA; Schüle, R; Schöls, L; La Piana, R; Synofzik, M; Zuchner, S; Brais, B
Source
The Canadian Journal of Neurological Sciences; June 2023, Vol. 50 Issue: Supplement 2 pS46-S46, 1p
Subject
Language
ISSN
03171671
Abstract
Background: The late-onset cerebellar ataxias (LOCAs) have until recently resisted molecular diagnosis. Contributing to this diagnostic gap is that non-coding structural variations, such as repeat expansions, are not fully accessible to standard short-read sequencing analysis. Methods: We combined bioinformatics analysis of whole-genome sequencing and long-read sequencing to search for repeat expansions in patients with LOCA. We enrolled 66 French-Canadian, 228 German, 20 Australian and 31 Indian patients. Pathogenic mechanisms were studied in post-mortem cerebellum and induced pluripotent stem cell (iPSC)-derived motor neurons from 2 patients. Results: We identified 128 patients who carried an autosomal dominant GAA repeat expansion in the first intron of the FGF14gene. The expansion was present in 61%, 18%, 15% and 10% of patients in the French-Canadian, German, Australian and Indian cohorts, respectively. The pathogenic threshold was determined to be (GAA)≥250, although incomplete penetrance was observed in the (GAA)250-300range. Patients developed a slowly progressive cerebellar syndrome at an average age of 59 years. Patient-derived post-mortem cerebellum and induced motor neurons both showed reduction in FGF14RNA and protein expression compared to controls. Conclusions: This intronic, dominantly inherited GAA repeat expansion in FGF14represents one of the most common genetic causes of LOCA uncovered to date.