To mention some, the peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), the peroxisome proliferator-activated receptor delta (PPARD), the mitochondrial transcription factor A (TFAM) and the myocyte enhancer factor 2A (MEF2A); interestingly, many of these genes are hypermethylated in diabetes [75], and this can explain why regular exercise inversely correlates with metabolic diseases [76]. The gene discussed is MEF2A; the disease is diabetes mellitus.