Mitofusin 2 (Mfn 2) is mostly expressed in the heart and muscle tissues. It is a transmembrane protein that mediates mitochondria fusion and plays a central role in the maintenance of mitochondrial morphology. A GTPase domain is required for the function of Mitofusin proteins. Mutations in Mfn2 can lead to Charcot-Marie-Tooth disease, a common inherited disorder of the peripheral nervous system. Mfn2 may also be associated with obesity and/or apoptosis.