In summary, heterozygous SPG7 mutations affecting the AAA+ domain of the encoded protein paraplegin were detected in 4.2% of European ALS patients showing partial phenotypic overlap with SPG7-associated HSP and with FTD, and were overrepresented in ALS patients with cerebellar dysfunction and flail arm or flail leg syndrome. This evidence concerns the gene SPG7 and amyotrophic lateral sclerosis.