MT-RNR2 and neurodegenerative disease: Humanin (HN) is a mitochondrial-derived polypeptide (24-mer) encoded by mtDNA that regulates mitochondrial functions under stress conditions and protects cells against various situations such as diabetes mellitus, cardiovascular and neurodegenerative diseases mainly through anti-apoptotic effects leading to sequestration of BAX and Bid (132) (Figure 1).