Cerebellar ataxia, neuropathy and vestibular areflexia syndrome (CANVAS): a family with five affected sibs from Turkey

Abstract

BackgroundCerebellar ataxia, neuropathy and vestibular areflexia syndrome (CANVAS), a relatively common cause of late-onset progressive ataxia, is a genetic disease characterised by biallelic pentanucleotide AAGGG repeat expansion in intron 2 of the replication factor complex subunit 1 gene. Herein, we describe the first molecularly confirmed CANVAS family with five affected siblings from Turkey.Case presentationThe family comprised seven siblings born from healthy non-consanguineous parents. CANVAS phenotype was present in five of them;two were healthy and asymptomatic. Chronic cough was the first symptom reported in all five siblings, followed by the development of sensory symptoms, oscillopsia and imbalance. Clinical head impulse test (HIT) was positive in all cases and video HIT performed on three patients revealed very low vestibulo-ocular reflex gains bilaterally. Magnetic resonance imaging and nerve conduction studies revealed cerebellar atrophy and sensory neuronopathy, respectively. RP-PCR confirmed the homozygous presence of the AAGGG repeat expansion in all five cases.ConclusionGenetic screening for CANVAS should be considered in all patients with late-onset ataxia, sensory disturbances and vestibular involvement, especially in the presence of chronic cough.