The fundamental importance of mitochondrial remodelling in mammalian pathophysiology has been underlined by in utero lethality and cerebellar degeneration in mice with homozygous mutations in Dnm1l itself, as well as Mfn1, Mfn2, or Opa1[23], [37], [38]. The gene discussed is MFN2; the disease is cerebellar degeneration.