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The Acknowledgements of this Letter should have included the following sentence: “This work was also supported in part by the University of Antwerp (TOP BOF 29069 to A.J.); the Fund for Scientific Research-Flanders (grant number G078414N to A.J.); the Association Belge contre les Maladies Neuromusculaire (to A.J.); the Association Française contre les Myopaties (grant number 16197 to A.J.).