DUX4 and myopathy: Other animal model work includes a mouse carrying human D4Z4 repeats (Krom et al., 2013), which showed some evidence of sporadic DUX4 expression but no myopathy, and adeno-associated viral (AAV) vector-mediated delivery of DUX4 to zebrafish and mouse skeletal muscle, which showed profound myopathy (Wallace et al., 2011).