DUX4 is a double homeobox transcription factor, and ectopic expression of full-length DUX4 (DUX4-FL) induces multiple molecular and cellular changes that may be linked to FSHD pathology through pathways that remain incompletely defined (Bosnakovski et al., 2017a; 2017b; Jones et al., 2020; Kowaljow et al., 2007; Mitsuhashi et al., 2013; 2018; Rickard et al., 2015). Here, DUX4 is linked to facioscapulohumeral muscular dystrophy.