RFC1-CANVAS: do we need to reevaluate autoimmune sensory neuro(no)pathies?

<h3>Introduction</h3> Sensory neuropathy is an uncommon manifestation of Sjogren syndrome. Diagnosis can be challenging and remains often uncertain. Recently, RFC1-CANVAS was discovered as a frequent cause of sensory neuro(no)pathy. <h3>Methods</h3> We present a patient initially diagnosed with Sjogren-related axonal sensory neuropathy who we later found to have biallelic RFC1 repeat expansions. <h3>Results</h3> A 45-year-old female developed acute burning dysesthesia in her hands and feet followed by numbness of her extremities. Neurological examination and nerve conduction studies showed a length-dependant, axonal, sensory neuropathy. She simultaneously complained of dry eyes, throat, and chronic cough. Lip biopsy showed lymphocytic and plasma cell infiltration. ENA antibodies were negative. She was diagnosed with Sjogren-related inflammatory sensory neuropathy and treated with hydroxychloroquine. At age 61, as the disease progressed with gait impairment, we undertook RFC1 testing which revealed biallelic pathogenic expansions. There was no cerebellar or vestibular involvement. Seven similar cases have been reported in the literature so far. <h3>Conclusion</h3> RFC1-CANVAS is a common cause of sensory neuro(no)pathy. In this case it is likely that the Sjogren’s diagnosis was incorrect. We propose that a proportion of so-called ‘inflammatory’ sensory neuropathies will actually have CANVAS. This is important considering potential unnecessary use of immunosuppressive therapies.