[Chronic Cough in CANVAS]

Among patients with RFC1 spectrum disorders represented by the phenotype of cerebellar ataxia with neuropathy and vestibular areflexia syndrome (CANVAS), at least 60% are known to manifest chronic, paroxysmal, and spasmodic dry cough. Chronic cough is a key diagnostic feature of RFC1-related diseases. It is often the first symptom and, in some cases, precedes neurological symptoms such as ataxia and sensory disturbance for more than 30 years. Although the pathogenesis of the cough remains unclear, it is possible that impairment of the vagus nerve, which includes an afferent pathway of the cough reflex, or the cerebellum would have contributed to the generation of the cough.