To study Duchenne muscular dystrophy (DMD), they knocked out exon 50 of the dystrophin gene in the WT-Dmd-Luc mouse, resulting in a frameshift mutation starting from exon 51, including the luciferase gene, creating the ΔEx50-Dmd-Luc DMD disease mouse model (Table 1). Here, DMD is linked to Duchenne muscular dystrophy.