CANVAS syndrome [1 gene]

CANVAS syndrome (cerebellar ataxia, neuropathy and vestibular areflexia syndrome) is characterized by a complex disturbance of balance and coordination with a peripheral, vestibular, and cerebellar origin.

Symptoms include unsteadiness (imbalance and dizziness), falls, and clumsiness of hands. Examination reveals progressive ataxia of gait and limb dysmetria. Patients present with neuropathy, bilateral vestibular areflexia, cerebellar dysfunciton, chronic cough (with or without associated gastroesophageal reflux) and autonomic dysfunction.

The inheritance pattern is autosomal recessive. The main cause is a biallelic intronic expansion in the RFC1 gene. Patients carrying an expansion in one allele and a point variant in the other have recently been described (PMID: 35883251, 36289003).

Patients carrying an expansion in one of the RFC1 alleles, with clinical features compatible with CANVAS syndrome.