DUX4 and facioscapulohumeral muscular dystrophy: Expression of DUX4 and DUX4-target genes were considerably upregulated in FSHD grafts relative to controls, with FSHD grafts showing positive immunostaining for the protein marker SLC34A2, demonstrating that this system recapitulates many established aspects of FSHD (Mueller et al., 2019).