While ACC and CANVAS have high diagnostic value for underlying RFC1 disease, our findings highlight that they should not be seen as monolithic syndromic entities but rather as 2 instances of variable clusters along a continuous overlapping spectrum of RFC1 disease with variable combinations of 5 recurrent core features: cerebellar ataxia, sensory neuropathy, vestibulopathy, cough, and autonomic dysfunction. Here, RFC1 is linked to Abnormal autonomic nervous system physiology.