A series findings by Zorzano's group also showed that altered expression of OPA1 and decreased expression of MFN2 participated in the development of obesity and type 2 diabetes in both patients and rodent models [32], [34], [35], [36], [37], which highlighted the importance of MFN2 in metabolism. The gene discussed is MFN2; the disease is obesity due to melanocortin 4 receptor deficiency.