title: [Mitochondrial DNA mutations in patients with chronic progressive external ophthalmoplegia and Kearns-Sayre syndrome].
abstract: OBJECTIVE
  Kearns-Sayre syndrome (KSS) and chronic progressive external ophthalmoplegia (CPEO) belong to neurological diseases caused by a defect in the energy-producing system of mitochondria, and are known to be associated with a deletion in the mitochondrial genome. This study was aimed to understand with greater clearness the characteristics of mitochondrial DNA (mtDNA) mutations in 11 Chinese patients with CPEO (7 cases) or KSS (4 cases).
  
  
  METHODS
  Densitometry of the bands on Southern blot, polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and sequencing were performed to search large scale deletions and A3243G point mutation in patients' muscle mtDNA.
  
  
  RESULTS
  Large deletions in mtDNA were detected in 2 CPEO and 3 KSS patients, the size of deletion ranged from 3.0 kb to 8.0 kb. Moreover, mtDNA A3243G point mutation was identified in 1 KSS patient. The proportion of mutant mtDNA was 37.6%-87.0%. Direct sequencing of the PCR products revealed 5 novel large deletions not reported by others.
  
  
  CONCLUSIONS
  The findings in this study being consistent with the reports by others, large scale deletions of mtDNA are frequently found in Chinese patients with KSS and CPEO. mtDNA A3243G mutation may also exist in some patients with KSS and CPEO.
authors.affiliation: Department of Neurology, First Hospital of Peking University, Beijing, PR China. snowplin@public3.bta.net.cn
authors.forename: Zhao-xia
authors.initials: ZX
authors.lastname: Wang
authors.forename: Yun
authors.initials: Y
authors.lastname: Yuan
authors.forename: Feng
authors.initials: F
authors.lastname: Gao
authors.forename: Yu
authors.initials: Y
authors.lastname: Qi
authors.forename: Ding-guo
authors.initials: DG
authors.lastname: Shen
authors.forename: Qing-tang
authors.initials: QT
authors.lastname: Chen
mesh_terms: D000293:Adolescent; D000328:Adult; D015139:Blotting, Southern; D002648:Child; D004252:DNA Mutational Analysis; D004272:DNA, Mitochondrial / Q000737:chemistry / Q000235:genetics*; D005260:Female; D017353:Gene Deletion; D006801:Humans; D007625:Kearns-Sayre Syndrome / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D017246:Ophthalmoplegia, Chronic Progressive External / Q000235:genetics*; D017354:Point Mutation; D016133:Polymerase Chain Reaction / Q000379:methods; D012150:Polymorphism, Restriction Fragment Length
chemical_list: D004272:DNA, Mitochondrial