Severe distinct dysautonomia in RFC1‐related disease associated with Parkinsonism

Biallelic repeat expansions in replication factor C subunit 1 (RFC1) have recently been found to cause cerebellar ataxia, neuropathy and vestibular areflexia syndrome (CANVAS). Additional features that have been described include Parkinsonism and a multiple system atrophy (MSA)‐like syndrome. CANVAS can include features of dysautonomia, but they are much milder than typically seen in MSA. We report a detailed autonomic phenotype of multisystem RFC1‐related disease presenting initially as CANVAS. Our patient presented aged 61 with a sensory ataxic neuropathy who rapidly developed widespread autonomic failure and Parkinsonism. The autonomic profile was of a mixed pre‐ and post‐ganglionic syndrome with progressive involvement of sympathetic and parasympathetic cardiovascular and sudomotor function. The Parkinsonism did not respond to levodopa. We present a patient with CANVAS and biallelic RFC1 expansions who developed Parkinsonism with severe autonomic involvement similar to that seen in classical MSA. The link between MSA and CANVAS remains uncertain.