Pfeffer et al found novel mutation in 3 persons and pointed out that SPG 7 mutation could cause progressive ophthalmoplegia through disordered mitochondrial maintenance.9 Van Gassen et al discovered 14 previously unreported mutations.10 SPG 7 encodes ‘paraplegin’, a mitochondrial AAA metalloprotease which works closely with another protein AFG3L2. Here, AFG3L2 is linked to ophthalmoplegia.