DUX4 and facioscapulohumeral muscular dystrophy: It would also be informative to determine if DUX4-FL-induced γH2AX immunostaining is reversible upon cessation of DUX4-FL expression, as well as to determine the frequency of γH2AX-positive nuclei in FSHD patient myofibers in comparison to the low frequency of TUNEL-positive myonuclei (Hauerslev et al., 2013; Sandri et al., 2001; Statland et al., 2015).