DUX4 and facioscapulohumeral muscular dystrophy: All in vitro and in vivo FSHD models confirmed a significant decrease of DUX4-fl transcript expression levels associated with an inhibition of DUX4-fl activity, as multiple target genes (TRIM43, MBD3L2, and ZSCAN4) were also efficiently down regulated [46], thereby confirming the therapeutic properties of AOs and morpholinos in correcting DUX4-mediated toxicity in skeletal muscle.