Using a previously described FSHD patient-derived myoblast cell line with an integrated fluorescent DUX4 reporter [7], DeSimone developed a high content imaging assay to accurately quantify metrics such as number of DUX4 activation events in a myotube and the survival time following DUX4 activation to track DUX4-induced myotoxicity. Here, DUX4 is linked to facioscapulohumeral muscular dystrophy.