Category: Cognitive Disorders (non-PD)
Objective: To determine the frequency and severity of cognitive impairment in RFC1-positive patients and comprehensively describe the pattern of cognitive disorders.
Background: Cerebellar ataxia, neuropathy, vestibular areflexia syndrome (CANVAS) is an adult-onset, slowly progressive disorder caused by a biallelic intronic repeat expansion in the replication factor complex subunit 1 (RFC1) gene. The classic phenotype associates sensory neuronopathy, cerebellar and sensory ataxia, vestibular areflexia and dry spasmodic cough. While cognitive impairment was previously reported, limited information is available regarding the impact of CANVAS on cognitive function.
Method: Individuals with molecularly characterized RFC1 biallelic (AAGGG)n expansions were proposed a comprehensive neuropsychological assessment. Overall cognitive efficiency, the cerebellar cognitive affective/Schmahmann syndrome as well as the main cognitive domains were assessed. Demographic and clinical characteristics were also recorded. Volume of the cerebellum and its lobules was measured in those who underwent a 3T-MRI scan.
Results: Twenty-one participants from unrelated families underwent a complete assessment, including 71% scoring lower than the cut-off at the Montreal Cognitive assessment and 71% having a definite cerebellar cognitive affective/Schmahmann syndrome. Three patients had dementia and 7 met the criteria of the mild cognitive impairment. Severity of cognitive impairment did not correlate with severity of clinical manifestations. Performance at memory and visuospatial functions tests was negatively correlated with the severity of cerebellar manifestations. Severity of the cerebellar cognitive affective/Schmahmann syndrome tended to be correlated with the volume of the cerebellum and of lobule IX.
Conclusion: Cognitive manifestations are frequent in RFC1-related disorders. They should be included in the phenotype and screened more systematically.
To cite this abstract in AMA style:
K. Dujardin, C. Tard, E. Diglé, V. Herlin, E. Mutez, JB. Davion, A. Wissocq, V. Delforge, G. Kuchcinski, V. Huin. CANVAS: think to assess cognition! [abstract]. Mov Disord. 2024; 39 (suppl 1). https://www.mdsabstracts.org/abstract/canvas-think-to-assess-cognition/. Accessed June 15, 2025.« Back to 2024 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/canvas-think-to-assess-cognition/