A novel SACS gene mutation in a Tunisian family

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is a distinct form of hereditary early-onset spastic ataxia. In 2000, the causative gene, SACS, encoding the protein sacsin, was identified in Quebec patients. The open reading frame (ORF) of SACS was initially reported to contain 11,487 bp and to be encoded by a single gigantic exon. Recently, eight additional exons upstream of the original ORF were found (ENST00000382298). We report four Tunisian ARSACS patients homozygous for a novel mutation in SACS exon 9 gene, c.12846_12850delAGAG. This mutation is localized upstream from the DnaJ domain leading to the loss of this domain, suggesting that the disease is associated with loss of critical chaperone function of sacsin.