A CCG expansion in ABCD3 causes oculopharyngodistal myopathy in individuals of European ancestry
Andrea Cortese, Sarah J. Beecroft, Stefano Facchini, Riccardo Curró, Macarena Cabrera‐Serrano, Igor Stevanovski, Sanjog R. Chintalaphani, Hasindu Gamaarachchi, Ben Weisburd, Chiara Folland, Gavin Monahan, Carolin K. Scriba, Lein Dofash, Mridul Johari, Bianca R. Grosz, Melina Ellis, Liam G. Fearnley, Rick M. Tankard, Justin Read, Ashirwad Merve, Natalia Dominik, Elisa Vegezzi, Ricardo Parolin Schnekenberg, Gorka Fernández‐Eulate, Marion Masingue, Diane Giovannini, Martin B. Delatycki, Elsdon Storey, M.D. Gardner, David J. Amor, Garth A. Nicholson, Steve Vucic, Robert D. Henderson, Thomas Robertson, Jason Dyke, Vicki Fabian, Frank Mastaglia, Mark R. Davis, Marina Kennerson, OPDM study group, Piraye Oflazer, Nazlı Başak, Hülya Kayserili, Gözde Yeşil, Edoardo Malfatti, James B Lilleker, Matthew Wicklund, Robert D. S. Pitceathly, Stefen Brady, Bernard Brais, David Pellerin, Stephan Züchner, Matt C. Danzi, Marina Grandis, Giacomo P. Comi, Stefania Corti, Elena Abati, Antonio Toscano, Arianna Manini, Arianna Ghia, Cristina Tassorelli, Ilaria Quartesan, Roberto Simone, Alexander M. Rossor, Mary M. Reilly, Liam Carroll, Volker Straub, Bjarne Udd, Zhiyong Chen, Gisèle Bonne, Rosaline C. M. Quinlivan, Simon Hammans, Arianna Tucci, Melanie Bahlo, Catriona McLean, Nigel G. Laing, Tanya Stojkovic, Henry Houlden, Michael G. Hanna, Ira W. Deveson, Paul J. Lockhart, Phillipa J. Lamont, Michael Fahey, Enrico Bugiardini, Gianina Ravenscroft
Abstract
Oculopharyngodistal myopathy (OPDM) is an inherited myopathy manifesting with ptosis, dysphagia and distal weakness. Pathologically it is characterised by rimmed vacuoles and intranuclear inclusions on muscle biopsy. In recent years CGG • CCG repeat expansion in four different genes were identified in OPDM individuals in Asian populations. None of these have been found in affected individuals of non-Asian ancestry. In this study we describe the identification of CCG expansions in ABCD3, ranging from 118 to 694 repeats, in 35 affected individuals across eight unrelated OPDM families of European ancestry. ABCD3 transcript appears upregulated in fibroblasts and skeletal muscle from OPDM individuals, suggesting a potential role of over-expression of CCG repeat containing ABCD3 transcript in progressive skeletal muscle degeneration. The study provides further evidence of the role of non-coding repeat expansions in unsolved neuromuscular diseases and strengthens the association between the CGG • CCG repeat motif and a specific pattern of muscle weakness.