Autosomal Recessive Spastic Ataxia of Charlevoix-Saguenay (ARSACS): Clinical, Radiological and Epidemiological Aspects

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) (OMIM #270550) was originally found among inhabitants of the Charlevoix-Saguenay region of Quebec (Bouchard et al., 1978). ARSACS patients in Quebec show uniform phenotypes characterized by early-onset spastic ataxia, peripheral neuropathy, retinal hypermyelination, hand or foot deformities, and normal mentality. In 2000, the SACS gene, which is responsible for ARSACS, was identified in Quebec patients (Engert et al., 2000). Since then, ARSACS has been reported worldwide, especially in the Mediterranean area (El Euch-Fayache et al., 2003; Criscuolo et al., 2004; Grieco et al., 2004; Richter et al., 2004) and Japan (Ogawa et al., 2004; Takiyama, 2006). More SACS gene mutations were also identified in other areas (Takiyama, 2007; Ouyang et al., 2008; Vermeer et al., 2008; Gerwig et al., 2010). Meanwhile, ARSACS in non-Quebec patients, especially in Japanese ones, showed marked clinical heterogeneity, i.e., there were patients without spasticity (Shimazaki et al., 2005; Hara et al., 2007; Shimazaki et al., 2007), without retinal hypermyelination (Hara et al., 2007), and with decreased mentality (Shimazaki et al., 2005; Yamamoto et al., 2005; Shimazaki et al., 2007; Hara et al., 2005). The clinical spectrum of the sacsinpathies will expand with the identification of more SACS gene mutations (Gomez, 2004).