The importance of MFN2 is evident from studies led in Mfn2 knock-out (KO) mice, which do not survive past midgestation, and homozygous mutants that die postnatally.20,22 Intriguingly, in a mouse model of amyotrophic lateral sclerosis, the MFN2 protein was found to interact with TDP-43, a protein involved in the pathogenesis and neuropathology of frontotemporal dementia and amyotrophic lateral sclerosis.23 Here, TARDBP is linked to frontotemporal dementia.