DUX4 and facioscapulohumeral muscular dystrophy: showed the use of locked nucleic acid (LNA) and 2′-O-methoxyethyl (2′-MOE) gapmer ASOs that support the breakdown of DUX4 mRNA by RNase H.18,19In vitro, different gapmer ASOs, mostly targeting exon 3, reduced the expression of DUX4 and DUX4 target genes in immortalized FSHD myotubes.