As such, individuals with FSHD exhibit indirect evidence of DUX4 protein expression in muscle biopsies (Yao et al., 2014), which leads to an inability to properly replace diseased or damaged muscle tissue with new myofibers (Bosnakovski et al., 2018) which may lead to a pro-adipogenic state within muscle of adults with FSHD. Here, DUX4 is linked to facioscapulohumeral muscular dystrophy.