ERLIN2 mutations are responsible for SPG18 (Yıldırım et al. 2011; Alazami et al. 2011; Wakil et al. 2013) but also account for juvenile primary lateral sclerosis, another neurodegenerative disorder of the upper motor neuron overlapping HSP phenotype (Al-Saif et al. 2012). This evidence concerns the gene ERLIN2 and hereditary spastic paraplegia.