In autosomal‐recessive spastic ataxia of Charlevoix Saguenay (ARSACS, because of biallelic mutations in SACS), abnormally elevated calcium‐rises in primary Sacs−/− PNs were described as the result of defective mitochondria and ER transport to the dendrites, because of intermediate filament cytoskeleton alterations (see Fig 3).116. Here, SACS is linked to Autosomal recessive spastic ataxia of Charlevoix-Saguenay.