MFF and Encephalopathy: These mitochondrial defects result in a specific clinical phenotype in human patients with MFF variants, which is termed ‘encephalopathy due to defective mitochondrial and peroxisomal fission 2’ (OMIM# 617086, Shamseldin et al., 2012; Koch et al., 2016; Nasca et al., 2018; Panda et al., 2020).