Yet, optic atrophy is found associated with spastic paraplegia linked to recessive mutations in SPG7, the paralog of AFG3L2 encoding another component of the m-AAA protease involved in OPA1 proteolytic maturation (Casari et al., 1998; Arnoldi et al., 2008). Here, AFG3L2 is linked to Leber hereditary optic neuropathy.