Figure 4.

Factors contributing to clinical variability in Duchenne and Becker muscular dystrophies. Shown is a schematic of progressive MRI findings, with gradual fibrofatty replacement over time (from Godi et al., 2016, mod.) ¹⁷. The progressive clinical phenotypes of both Duchenne and Becker muscular dystrophies is driven predominantly by the extent of fibrofatty replacement of muscle. The factors driving the fibrofatty replacement are listed for both Duchenne and Becker dystrophy, as discussed in the text. Plus and minus refer to later or earlier age at loss of ambulation.