Clinical Guidance

ARSACS (autosomal recessive spastic ataxia of Charlevoix-Saguenay) defines a spastic ataxia first described in 1978 among a cohort of about 325 French-Canadian individuals from 200 families born in the Saguenay-Lac-St-Jean area of northeastern Quebec . The disorder has since been identified in other areas of the world . Most individuals display a slowly progressive course of unsteadiness, often with onset before age ten years (usually of late-infantile onset) and associated with spasticity during childhood and neuropathy during teenage years. In addition to the classic triad of symptoms of progressive cerebellar ataxia, peripheral neuropathy, and lower-limb spasticity, some individuals with ARSACS have features such as hearing loss, intellectual disability, and myoclonic epilepsy [, , , , , ]. Furthermore, absence of one of the three defining clinical features has been described in several individuals [, , , , , ]. Both intra- and interfamilial phenotypic variability has been observed in ARSACS. To date, more than 190 individuals have been identified with biallelic pathogenic variants in SACS [, , , , , ] (LOVD3 Database). The following table of the phenotypic features associated with this condition is based on the table in the publication of . Note: Not all features were measured in the different groups of affected individuals; some relative frequencies are less representative due to a lower total number of individuals measured. Table 2. Features of ARSACS

Diagnostic Criteria

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is clinically characterized by a progressive cerebellar ataxia, peripheral neuropathy, and spasticity. Onset of classic ARSACS is often in early childhood, often leading to delayed walking because of gait unsteadiness in very young toddlers. Recent advances in molecular genetic testing have confirmed that ARSACS is one of the most prevalent autosomal recessive ataxia disorders worldwide.

Suggestive Findings

ARSACS should be suspected in individuals with the following cluster of symptoms:

Management Guidelines

Evaluations Following Initial Diagnosis To establish the extent of disease and needs in an individual diagnosed with ARSACS, the evaluations summarized (if not performed as part of the evaluation that led to the diagnosis) are recommended. Table 4. Recommended Evaluations Following Initial Diagnosis in Individuals with ARSACS

Surveillance Guidelines

Table 6.

Recommended Surveillance for Individuals with ARSACS

System/Concern | Evaluation | Frequency

Neurologic

| Complete neurologic assessment | Annually

Gait fine motor assessment | As needed

Speech assessment