An inherited large-scale rearrangement in SACS associated with spastic ataxia and hearing loss

Autosomal recessive spastic ataxia of Charlevoix-Saguenay is a neurodegenerative disorder characterized by early-onset, spastic ataxia and peripheral neuropathy, with or without mental retardation. The array of mutations in SACS has expanded worldwide after the first description in Quebec. We herein report the identification of an unconventional SACS mutation, a large-scale deletion sized approximately 1.5 Mb encompassing the whole gene, in two unrelated patients. The clinical phenotype of the patients was similar to more canonical ARSACS cases, though it is was complicated by the unusual presence of hearing loss. Our findings suggest that a "microdeletion" on chromosome 13q12 represents a novel allelic variant associated with ARSACS, stressing the need for an expanded testing in molecular diagnostic laboratories.