The most prevalent form of FSHD (FSHD1) is associated with a contraction of the D4Z4 macrosatellite region on chromosome 4q35, leading to the inappropriate transcription of the double homeobox 4 (DUX4) gene [2, 3], which is normally silenced in skeletal muscle. Here, DUX4 is linked to facioscapulohumeral muscular dystrophy.