Cerebellar Ataxia, Neuropathy, and Vestibular Areflexia Syndrome (CANVAS): A case report of RFC1-associated disease

Cerebellar ataxia, neuropathy, and vestibular areflexia syndrome (CANVAS) is a late-onset neurodegenerative disorder associated with biallelic RFC1 repeat expansions. We report a 55-year-old woman with progressive imbalance, sensory neuronopathy, bilateral vestibular hypofunction, chronic cough, and orthostatic symptoms. MRI demonstrated cerebellar atrophy involving the vermis, particularly the posterior vermis, with additional involvement of the posterosuperior cerebellar hemispheres, including Crus I, and upper cervical spinal cord atrophy. Integration of the characteristic imaging pattern with the clinical, electrophysiologic, and vestibular findings raised suspicion for RFC1 -associated disease and prompted targeted genetic testing, which demonstrated biallelic pathogenic AAGGG repeat expansions in RFC1 . This case emphasizes the educational value of recognizing the characteristic neuroradiologic pattern of RFC1 -associated CANVAS in patients with adult-onset progressive ataxia and its role in guiding appropriate targeted genetic evaluation.