title: [Clinical heterogeneity associated with mitochondrial DNA A8344G point mutation].
abstract: OBJECTIVE
  To report the clinical features of mitochondrial disease caused by mitochondrial DNA (mtDNA) A8344G point mutation.
  
  
  METHODS
  We analyzed the clinical presentations and muscular pathological changes in 10 patients with genetically confirmed mtDNA A8344G point mutation.
  
  
  RESULTS
  Among them, 6 patients presented as juvenile-onset myoclonic epilepsy with ragged red fibers (MERRF) syndrome, 2 suffered infant-onset Leigh syndrome and the remaining 2 were diagnosed as limb-girdle mitochondrial myopathy. The mtDNA A8344G mutation load from muscle samples showed that patients with Leigh syndrome>MERRF syndrome>mitochondrial myopathy (87.2%, 88.4%>69.0%-86.8%>67.2%, 58.4%).
  
  
  CONCLUSIONS
  Mitochondrial disease caused by A8344G point mutation shows a great heterogeneity. The mutation load of muscle mtDNA might be associated with the severity of clinical phenotype, the higher mutation load, the more severe clinical presentations.
authors.affiliation: Department of Neurology, Peking University First Hospital, Beijing 100034, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Zhao
authors.forename: Dan-hua
authors.initials: DH
authors.lastname: Zhao
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: He
authors.initials: H
authors.lastname: Lü
authors.forename: Yun
authors.initials: Y
authors.lastname: Yuan
authors.forename: Yu
authors.initials: Y
authors.lastname: Qi
authors.forename: Zhao-xia
authors.initials: ZX
authors.lastname: Wang
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D004272:DNA, Mitochondrial / Q000235:genetics*; D005260:Female; D006801:Humans; D007223:Infant; D007888:Leigh Disease / Q000235:genetics; D017243:MERRF Syndrome / Q000235:genetics; D008297:Male; D008875:Middle Aged; D017240:Mitochondrial Myopathies / Q000235:genetics; D049288:Muscular Dystrophies, Limb-Girdle / Q000235:genetics; D017354:Point Mutation; D055815:Young Adult
chemical_list: D004272:DNA, Mitochondrial