In addition to peripheral neuropathy, patients with MFN2 variants can sometimes also present with additional phenotypes, including optical atrophy (Leonardi et al., 2015), sensorineural hearing loss (Chung et al., 2006), cerebellar ataxia (Sharma et al., 2021b) and multiple systemic lipomatosis (Capel et al., 2018), to name a few. This evidence concerns the gene MFN2 and hereditary optic atrophy.