CANVAS syndrome – the first genetically confirmed case in Bulgaria
Medical review (Med. pregled), 2023, 59(1), 58-62.
V. Nacheva1, G. Angov1,2, P. Dacheva1, I. Petrova1,2, M. Karadzhova1,2, Yu. Petrova1,2
1 Neurological Diseases Clinic, Aleksandrovska University Hospital – Sofia
2 Neurology Department, Medical University – Sofia
Abstract. Cerebellar Ataxia with Neuropathy and Bilateral Vestibular Areflexia Syndrome (CANVAS) is a hereditary form of ataxia characterized with a combination of bilateral vestibular, cerebellar and somatosensory damage. The relation of the bilateral vestibulopathy with the cerebellar ataxia was first reported in 1991 and was designated as a separate syndrome. In 2011, sensory deficiency was added, being an integral part of the syndrome. With some of the phenotype variants, autonomous dysfunction and/or coughing is found, as well as cognitive disorders. CANVAS is an autosomal recessive disease of late onset, and until recently the diagnosis was made only based on clinical phenotype. In 2019, Cortese et al. found a defect in RFC1 – biallelic pentanucleotide repetition within the gene of subunit 1 in RFC1, identified as the major cause in the majority of the CANVAS cases. In the following years, a number of variants have been identified – both pathological biallelic repetitions and elongated reference allele (ААААG). Here, the case of an 82-year-old patient with a typical clinical picture and genetically verified CANVAS is presented. The disease is of particular interest due to its slow progress, multi-systemic involvement and broad differential diagnosis. Also, the diagnostic and treatment methods, which are of major importance for the better symptomatic management, are discussed.
Key words: cerebellar ataxia, neuropathy, vestibular areflexia, CANVAS syndrom
Address for correspondence: Dr. Violina Nacheva, e-mail: nacheva.violina@gmail.com