title: Epileptic phenotypes in children with respiratory chain disorders.
abstract: OBJECTIVE
  Epilepsy is a commonly reported but rarely described clinical hallmark of mitochondrial respiratory chain defects (RCDs) with encephalopathy.
  
  
  METHODS
  From 1990-2006 we collected data about 56 children with RCD (single, n = 24 or multiple, n = 20 mitochondrial complex deficiencies; mtDNA mutation, n = 11; mtDNA depletion n = 10 of 21; and nuclear gene mutation n = 11). Epileptic features were reviewed retrospectively.
  
  
  RESULTS
  First seizures were frequently (47 patients, 82.5%) preceded by failure to thrive, psychomotor delay, ataxia, or multisystemic dysfunction. Sixty percent of the patients had several seizure types. Six age-related epilepsy phenotypes could be identified: status epilepticus complicating neonatal multivisceral deficiency (2 patients), neonatal myoclonic encephalopathy (3 patients), infantile spasms (8 patients), refractory or recurrent status epilepticus (21 patients), epilepsia partialis continua (4 patients), and myoclonic epilepsy (18 patients). Except for infantile spasms, epilepsy was difficult to control in most patients (95%). Valproate was administered to 25 patients, one of whom developed acute liver failure 6 days later. Twenty-two patients (45%) died, half of them within 9 months from the onset of epilepsy.
  
  
  CONCLUSIONS
  In RCD, epilepsy is not only difficult to control but its occurrence often indicates a severe turn in the course of the disease. For one-third of the patients, classical biochemical measures failed to reveal any abnormality and RCD could be detected in the liver only.
authors.affiliation: Pediatric Neurology, Hôpital Necker, APHP, Paris, France. isabelle.desguerre@nck.aphp.fr
authors.forename: Sandra
authors.initials: S
authors.lastname: El Sabbagh
authors.forename: Anne-Sophie
authors.initials: AS
authors.lastname: Lebre
authors.forename: Nadia
authors.initials: N
authors.lastname: Bahi-Buisson
authors.forename: Pascale
authors.initials: P
authors.lastname: Delonlay
authors.forename: Christine
authors.initials: C
authors.lastname: Soufflet
authors.forename: Nathalie
authors.initials: N
authors.lastname: Boddaert
authors.forename: Marlène
authors.initials: M
authors.lastname: Rio
authors.forename: Agnès
authors.initials: A
authors.lastname: Rötig
authors.forename: Olivier
authors.initials: O
authors.lastname: Dulac
authors.forename: Arnold
authors.initials: A
authors.lastname: Munnich
authors.forename: Isabelle
authors.initials: I
authors.lastname: Desguerre
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D004579:Electron Transport / Q000235:genetics; D004827:Epilepsy / Q000150:complications / Q000235:genetics* / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D028361:Mitochondrial Diseases / Q000150:complications / Q000235:genetics* / Q000503:physiopathology*; D010641:Phenotype; D012189:Retrospective Studies