SPG7 and nervous system disorder: The m‐AAA protease plays crucial roles to maintain mitochondrial homeostasis in neurons, as underlined by the spectrum of neurological diseases associated with mutations in genes encoding the individual subunits SPG7 and AFG3L2 (Casari et al., 1998; Di Bella et al., 2010; Eskandrani et al., 2017; Pierson et al., 2011).