DUX4 and facioscapulohumeral muscular dystrophy: In addition, 13% of the 144 DUX4-bound repetitive elements that form alternative promoters for annotated genes show FSHD-specific transcripts and HSATII is expressed at ∼26-fold higher levels in FSHD myotubes (median ∼2.2 reads per million) than control myotubes (median 0.08 reads per million).