Similarities also exist with the stimulation of FGF21 from skeletal muscle during conditions of muscle-specific mitochondrial disease, certain types of exercise, and hyperinsulinemia in mice and humans (Hojman et al., 2009; Crooks et al., 2014; Emanuelli et al., 2014; Tanimura et al., 2016; Staiger et al., 2017). This evidence concerns the gene FGF21 and mitochondrial disease.