MFN2 and Alzheimer disease: Wang et al. [57] showed that the expression of proteins involved in sizing and recycling mitochondria, such as dynamin-related protein 1 (Drp1) and fusion proteins, including optic atrophy protein 1 (OPA1), mitofusin 1 (Mfn1), and mitofusin 2 (Mfn2), is reduced, while for fission protein 1 (Fis1), gene expression is increased in AD postmortem hippocampal tissues.