DUX4 and Facioscapulohumeral dystrophy: Because we and others have previously shown that the use of antisense oligonucleotides targeting the 3′ end elements involved in DUX4 mRNA processing is an efficient therapeutic strategy for FSHD [19,20,21,22], in this study, we performed gene editing using transcription activator-like effector nuclease (TALEN) and CRISPR-Cas9 technology to permanently inhibit DUX4 expression by targeting its poly(A) signal sequence (PAS).