239 New de novo mutation in CACNA1a gene leading to episodic ataxia type 2

Abstract

Introduction andAimEpisodic ataxia (EA) is a group of inherited ion channel disorders affecting the cer- ebellum characterised by sporadic episodes of ataxia (Riant et al, 2011; Tomlinson et al, 2013). At least 7 different types have been identified, type 2 being the most common. We describe a patient present- ing with recurrent episodes of dizziness and gait disturbance with a novel mutation in CACNA1a gene (c.586del) leading to episodic ataxia type 2.Clinical presentationA 65-year old male presented with recurrent episodes of dizziness and gait distur- bance, which had been present since childhood but increased in severity over last 2 years and leading to hospitalisation. He also reported mild cognitive impairment. Examination showed bilateral horizontal jerky nyastagmus with an otherwise normal neurological examination.InvestigationsNeuroimaging studies showed mild small vessel disease. Genetic sequencing revealed a heterogenicity for the c.586del likely pathogenic frameshift mutation in exon 4 of the CACNA1A gene, resulting in targeting of the mRNA for nonsense- mediated decay or the production of a truncated protein leading to the diagnosis of autosomal dominant episodic ataxic type 2 in this patient.SummaryWe report a new de novo mutation in CACNA1a gene leading to episodic ataxia type 2. The patient was given acetazolamide (250mg/day) which improved his symptoms. Episodic ataxia should be considered in patients presenting with a history of intermittent dizziness.kitwu@doctors.org.uk