CAPN3 and Duchenne muscular dystrophy: The fact that Capn3 E6- is already increased in pre-symptomatic FRG1 mice (Figure 2b and Figure 9a) and that its expression is normal in the mouse model of Duchenne muscular dystrophy (Figure S4) suggests that altered Capn3 splicing is a primary consequence of FRG1 overexpression and is not simply secondary to muscle wasting.