Linking our findings of a reduced neurite growth in SPG11 MNs to previous studies that found abnormal axonal branching in SPG11 (Martin et al., 2012; Pérez-Brangulí et al., 2014), mitochondrial alterations in SPG11 might impair axonal maintenance and ultimately lead to the known phenotype of spastic paraplegia and motor neuropathy. The gene discussed is SPG11; the disease is Spastic paraplegia.