Sacsin is required for proper organization of neurofilaments in several types of neurons, including Purkinje and pyramidal neurons, and when mutated – as in the case of the hereditary disorder autosomal recessive spastic ataxia of the Charlevoix-Saguenay – leads to abnormal somatodendritic bundles of neurofilaments (Gentil et al., 2019; Larivière et al., 2019). This evidence concerns the gene SACS and autosomal recessive spastic ataxia.