The pathogenic m.3243A>T mitochondrial DNA mutation is associated with a variable neurological phenotype

Neuromuscul Disord. 2010 Jun;20(6):403-6. doi: 10.1016/j.nmd.2010.04.003. Epub 2010 May 14.


The m.3243A>G point mutation in the mitochondrial tRNA(Leu(UUR)) (MTTL1) gene is a common cause of mitochondrial DNA disease and is associated with a variety of clinical presentations. A different mutation occurring at the same site - an m.3243A>T transversion - is less prevalent, but has previously been observed in two patients with encephalopathy and lactic acidosis. We report the investigations of a further two patients with the m.3243A>T mutation who presented with either a chronic progressive external ophthalmoplegia (CPEO) phenotype or sensorineural hearing loss, with single fibre mutation studies confirming segregation of the m.3243A>T mutation with COX deficiency.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acidosis, Lactic / genetics
  • Adult
  • Brain Diseases / etiology
  • Brain Diseases / genetics
  • DNA, Mitochondrial / genetics*
  • Family
  • Female
  • Humans
  • Immunohistochemistry
  • Male
  • Mitochondrial Diseases / genetics
  • Muscle Fibers, Skeletal / pathology
  • Muscle, Skeletal / pathology
  • Mutation / genetics*
  • Nervous System Diseases / genetics*
  • Nervous System Diseases / pathology
  • Ophthalmoplegia / genetics
  • Ophthalmoplegia / pathology
  • Phenotype
  • Prostaglandin-Endoperoxide Synthases / deficiency
  • Prostaglandin-Endoperoxide Synthases / genetics
  • Reverse Transcriptase Polymerase Chain Reaction
  • Young Adult


  • DNA, Mitochondrial
  • Prostaglandin-Endoperoxide Synthases