Nevertheless, each of the experimental drugs which failed in clinical testing were shown to modify the disease course of murine DMD in the gold standard mdx mouse model [29,30,31,32], albeit, only some of these studies used sexually mature mice [29,32] as opposed to juvenile mice [30,31], which are likely to be more amenable to myostatin inhibition [33] through hyperplasia. This evidence concerns the gene MSTN and Duchenne muscular dystrophy.