SACS and Autosomal recessive spastic ataxia of Charlevoix-Saguenay: We previously found that the absence of sacsin affects intermediate filament (IF) organization, with abnormal bundles of vimentin in fibroblasts of patients with ARSACS (12) and of neurofilament (NFs) in brain autopsies of patients with ARSACS and in the Sacs–/– mouse (8).