ARL6IP1 and hereditary spastic paraplegia: Compared with other SPG mouse models (SPG11 and SPG15), the Arl6ip1−/− mouse model showed a similar pathogenic phenotype, such as CC thinning (TCC), which is the most common cause of AR-HSP and extensive white matter abnormalities (França et al., 2012; Riverol et al., 2009; Khundadze et al., 2013; Beetz et al., 2013).