From OMIM
Autosomal recessive spastic ataxia of Charlevoix-Saguenay (SACS, or ARSACS) is a complex neurodegenerative disorder usually characterized by early childhood onset of cerebellar ataxia, pyramidal tract signs, and peripheral neuropathy. Most patients become wheelchair-bound; cognitive function is usually not affected. Some patients may have atypical features, such as later onset or initial presentation of peripheral neuropathy (summary by Baets et al., 2010).  http://www.omim.org/entry/270550

From MedlinePlus Genetics
Autosomal recessive spastic ataxia of Charlevoix-Saguenay, more commonly known as ARSACS, is a condition affecting muscle movement. People with ARSACS typically have abnormal tensing of the muscles (spasticity), problems with balance and coordination (cerebellar ataxia), and reduced sensation and weakness in the arms and legs (peripheral neuropathy).

Additional muscle problems that can occur in ARSACS include muscle wasting (amyotrophy), involuntary eye movements (nystagmus), and difficulty swallowing (dysphagia) and speaking (dysarthria). Other features of ARSACS involve high-arched feet (pes cavus), a spine that curves to the side (scoliosis), yellow streaks of fatty tissue in the light-sensitive tissue at the back of the eye (hypermyelination of the retina), urinary tract problems, intellectual disability, hearing loss, and recurrent seizures (epilepsy).

An unsteady walking style (gait) is the first symptom of ARSACS. Walking problems usually begin between the ages of 12 months and 18 months, as toddlers are learning to walk. These movement problems worsen over time, with increased spasticity and ataxia of the arms and legs. In some cases spasticity goes away, but this apparent improvement is thought to be due to the wasting away (atrophy) of nerves in the arms and legs. Most affected individuals require wheelchair assistance by the time they are in their thirties or forties.

While this condition was named after the area in which it was first seen, the Charlevoix-Saguenay region of Quebec, Canada, ARSACS has been identified in individuals worldwide.  https://medlineplus.gov/genetics/condition/autosomal-recessive-spastic-ataxia-of-charlevoix-saguenay