2025 Volume 71 Issue 4 Pages 184-191
Cerebellar ataxia with neuropathy and vestibular areflexia syndrome (CANVAS) is characterized by a triad of bilateral vestibulopathy, cerebellar ataxia, and sensory neuropathy, resulting in extensive dysfunction of the balance-related systems. We herein report a case of CANVAS. The patient was a 73-year-old man who had experienced unsteadiness while walking for 7 years. He had been diagnosed with spinocerebellar degeneration 4 years prior. After relocation, he visited our hospital's neurology department. In addition to cerebellar and sensory system abnormalities, brain MRI showed mild cerebellar atrophy, which was disproportionate to the severity of gait unsteadiness. His unsteadiness worsened in darkness and on uneven ground, prompting a referral to our department for vestibular evaluation. Caloric testing revealed no bilateral responses, video head impulse testing showed abnormalities in all semicircular canals. No reproducible waveforms were observed in the cVEMP or oVEMP, indicating severe bilateral vestibular dysfunction. Genetic testing identified abnormal biallelic expansion of AAGGG repeats in RFC1, confirming the diagnosis of CANVAS. It is important to re-evaluate the diagnosis when the clinical findings are not consistent with the existing diagnosis.
