title: Epilepsy in adults with mitochondrial disease: A cohort study.
abstract: OBJECTIVE
  The aim of this work was to determine the prevalence and progression of epilepsy in adult patients with mitochondrial disease.
  
  
  METHODS
  We prospectively recruited a cohort of 182 consecutive adult patients attending a specialized mitochondrial disease clinic in Newcastle upon Tyne between January 1, 2005 and January 1, 2008. We then followed this cohort over a 7-year period, recording primary outcome measures of occurrence of first seizure, status epilepticus, stroke-like episode, and death.
  
  
  RESULTS
  Overall prevalence of epilepsy in the cohort was 23.1%. Mean age of epilepsy onset was 29.4 years. Prevalence varied widely between genotypes, with several genotypes having no cases of epilepsy, a prevalence of 34.9% in the most common genotype (m.3243A>G mutation), and 92.3% in the m.8344A>G mutation. Among the cohort as a whole, focal seizures, with or without progression to bilateral convulsive seizures, was the most common seizure type. Conversely, all of the patients with the m.8344A>G mutation and epilepsy experienced myoclonic seizures. Patients with the m.3243A>G mutation remain at high risk of developing stroke-like episodes (1.16% per year). However, although the standardized mortality ratio for the entire cohort was high (2.86), this ratio did not differ significantly between patients with epilepsy (2.96) and those without (2.83).
  
  
  CONCLUSIONS
  Epilepsy is a common manifestation of mitochondrial disease. It develops early in the disease and, in the case of the m.3243A>G mutation, often presents in the context of a stroke-like episode or status epilepticus. However, epilepsy does not itself appear to contribute to the increased mortality in mitochondrial disease.
authors.affiliation: Institute of Neuroscience, Henry Wellcome Building for Neuroecology, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Roger G
authors.initials: RG
authors.lastname: Whittaker
authors.affiliation: Wellcome Trust Center for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Helen E
authors.initials: HE
authors.lastname: Devine
authors.affiliation: Wellcome Trust Center for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Grainne S
authors.initials: GS
authors.lastname: Gorman
authors.affiliation: Wellcome Trust Center for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Schaefer
authors.affiliation: Institute of Genetic Medicine, International Center for Life, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Rita
authors.initials: R
authors.lastname: Horvath
authors.affiliation: Wellcome Trust Center for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Yi
authors.initials: Y
authors.lastname: Ng
authors.affiliation: Wellcome Trust Center for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Victoria
authors.initials: V
authors.lastname: Nesbitt
authors.affiliation: Wellcome Trust Center for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Nichola Z
authors.initials: NZ
authors.lastname: Lax
authors.affiliation: Wellcome Trust Center for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Robert
authors.initials: R
authors.lastname: McFarland
authors.affiliation: Institute of Neuroscience, Henry Wellcome Building for Neuroecology, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Mark O
authors.initials: MO
authors.lastname: Cunningham
authors.affiliation: Wellcome Trust Center for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Taylor
authors.affiliation: Wellcome Trust Center for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Douglass M
authors.initials: DM
authors.lastname: Turnbull
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D004272:DNA, Mitochondrial / Q000235:genetics*; D018450:Disease Progression; D004827:Epilepsy / Q000453:epidemiology / Q000209:etiology* / Q000401:mortality; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D028361:Mitochondrial Diseases / Q000150:complications* / Q000453:epidemiology / Q000235:genetics* / Q000401:mortality; D009154:Mutation; D015995:Prevalence; D020521:Stroke / Q000453:epidemiology / Q000209:etiology* / Q000401:mortality; D055815:Young Adult
chemical_list: D004272:DNA, Mitochondrial