Thus, DMD appears to affect the activity of the RyR1 in two opposite ways: (1) First, in early stages of myofiber damage, or in pre-apoptotic phases, the overall function of RyR1 is reduced, leading to depressed action potential-induced RyR1 Ca2+ release (Collet et al., 1999; Woods et al., 2004, 2005; Hollingworth et al., 2008; Lovering et al., 2009b; Hernández-Ochoa et al., 2015). This evidence concerns the gene RYR1 and Duchenne muscular dystrophy.