Abstract

Autosomal Recessive Spastic Ataxia of the Charlevoix-Saguenay (ARSACS) is a very rare neurodegenerative genetic disorder that primarily affects people from the Saguenay–Lac-Saint-Jean and Charlevoix regions of Quebec or descendants of native settlers in this region. This disorder has also been demonstrated in people from various other countries including India, Turkey, Japan, The Netherlands, Italy, Belgium, France and Spain. The prevalence has been estimated at about 1 in 1900 in Quebec, but it is very rare elsewhere.

Genetics

The inheritance pattern is autosomal recessive. The disorder is caused by a mutation in the SGCG on chromosome 13. The mutation of the SACS gene causes the production of an unstable, poorly functioning SACSIN protein. It is unclear as to how this mutation affects the central nervous system (CNS) and skeletal muscles presenting in the signs and symptoms of ARSACS.

Symptoms

ARSACS is usually diagnosed in early childhood, approximately 12–24 months of age when a child begins to take their first steps. At this time it manifests as a lack of coordination and balance resulting in frequent falls. Some of the signs and symptoms include:

- Stiffness of the legs

- Appendicular and trunk ataxia

- Hollow foot and hand deformities

- Ataxic dysarthria

- Distal muscle wasting

- Horizontal gaze nystagmus

- Spasticity

Prognosis

Most patients begin to use a wheelchair for movement around age 30-40. Death usually occurs in their 60s, but some have been reported to live longer.