Metabolic substrate switching that forces fibroblasts to use mitochondrial oxidative phosphorylation rather than non-mitochondrial glycolysis [18,19] previously induced mitochondrial shortening and other phenotypes in fibroblasts from a CMT2A patient carrying the MFN2 R274W mutation [20]. This evidence concerns the gene MFN2 and Charcot-Marie-Tooth disease type 2A1.