ARL6IP1 and hereditary spastic paraplegia: To investigate the mechanisms underpinning neurodegeneration due to loss of the ER-shaping protein ARL6IP1, mutations in which cause an autosomal-recessive form of HSP (SPG61), we generated novel models of disease by CRISPR/Cas9-mediated knockout of ARL6IP1 in Drosophila and a human cell line.