Abstract Details

Title Neuropathological Evidence That Dorsal Root Ganglionopathy Causes the Sensory Impairment in Cerebellar Ataxia with Neuronopathy and Bilateral Vestibular Areflexia Syndrome (CANVAS)

Topic Neuro-ophthalmology/Neuro-otology

Presentation(s) S47 - (-)

Poster/Presentation
Number 006

Objective

Background In 2004 we reported the association of bilateral vestibulopathy with cerebellar ataxia as a distinct syndrome with a characteristic clinical sign - an absent visually-enhanced vestibulo-ocular reflex. Later we showed in 18 patients that a non-length dependent peripheral neuropathy was an integral part of CANVAS (Cerebellar Ataxia Neuropathy bilateral Vestibular Areflexia Syndrome).

Design/Methods Prospective case series.

Results We have data from 41 patients with CANVAS, and brain and spine neuropathology from one and show that the underlying pathology is in sensory ganglia. Brain and temporal bone pathology in another patient showed marked loss of Purkinje cells and of vestibular, trigeminal and facial ganglion cells. All patients had brain MRI and 36/41 had evidence of cerebellar atrophy involving anterior and dorsal vermis, and hemispheric crus I. The phenotype can mimic that of SCA 3. There are 6 sets of sibling pairs, inferring CANVAS is a late-onset recessive disorder and identification of the culprit gene is currently a target of investigation.

Conclusions 1. A dorsal root ganglionopathy/neuronopathy is the cause of the peripheral sensory impairment in CANVAS, rather than a length-dependent sensory neuropathy. 2. CANVAS is likely to be a late-onset recessive disorder and we expect that recently acquired genetic information will lead to identification of the 'CANVAS gene' and subsequently a diagnostic gene test. 4. Clinically, CANVAS is a differential diagnosis for both spinocerebellar ataxia type 3 (Machado-Joseph disease) and Friedreich's ataxia.

Authors/Disclosures
David J. Szmulewicz, MD (Royal Victorian Eye & Ear Hospital) PRESENTER	No disclosure on file
John Waterston, MD, MBBS, FRACP (Cabrini Medical Centre)	No disclosure on file
	No disclosure on file
	No disclosure on file
Stuart S. Mossman, MD (Mossman Medical)	No disclosure on file
Andrew M. Chancellor, MD, FRACP (Tauranga Hospital)	No disclosure on file
	No disclosure on file
	No disclosure on file
	No disclosure on file
Leslie J. Roberts, MD (St Vincent's Hospital Melbourne)	No disclosure on file
Elsdon Storey, FRACP, DPhil (Monash University, ASPREE, SPHPM)	No disclosure on file
Michael G. Halmagyi, MD	Dr. Halmagyi has nothing to disclose.

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