DUX4 and facioscapulohumeral muscular dystrophy: Targeting the enzymatically inactive dSaCas9 fused to one of several epigenetic repressor domains to the DUX4 promoter/exon 1 increases chromatin repression at the disease locus, specifically repressing DUX4 and its target genes in FSHD myocytes and in a mouse model of the disease [83].