(A, B) Diagnostic mitochondrial respiratory complexes activities (complexes I–IV) measured in control and DNM1L patient P2 (p.Gly363Asp), P3* (age 13 yr), P3** (age 16 yr) (p.Leu230dup), and P4 (p.Arg710Gly) muscle (A), and in control and P2 fibroblasts (B). Data information: mitochondrial respiratory chain enzyme activities were normalized to the activity of the mitochondrial matrix enzyme, citrate synthase. Mean enzyme activities of control muscle (n = 25) or fibroblasts (n = 8) are set to 100%, and error bars represent SD.