MT-RNR2 and obesity due to melanocortin 4 receptor deficiency: Mitochondrial DNA also harbors a growing list of short open reading frames (sORFs) that encode mitochondrial-derived peptides with systemic functions, such as humanin (HN), which protect neurons from death caused by several early-onset familial AD genes [43], PD, cardiovascular diseases, inflammation, diabetes, obesity [44], and MOTS-c, which activates antioxidant response [45] and regulates insulin sensitivity [46].