A novel mutation (8342G → A) in the mitochondrial tRNA(Lys) gene associated with progressive external ophthalmoplegia and myoclonus

Valeria Tiranti, Franco Carrara, Paolo Confalonieri, Marina Mora, Raffaele M. Maffei, Eleonora Lamantea, Massimo Zeviani

Research output: Contribution to journalArticlepeer-review

Abstract

We describe a patient who suffered from impaired ocular motility from age 10 years and at 16 years developed ptosis, proximal weakness and progressive fatigability. At 35 years she developed massive myoclonic jerks, and head and distal tremor. A muscle biopsy showed a high percentage of cytochrome c oxidase negative fibers but no ragged-red fibers. A novel heteroplasmic mutation (8342G → A) was found in the mitochondrial transfer RNA(Lys) gene by single-strand conformation polymorphism screening, followed by sequence and restriction fragment length polymorphism analysis. Approximately 80% of muscle mitochondrial DNA (mtDNA) harbored the mutation, while the mutation was absent in lymphocyte DNA of the proband, as well as of her mother, daughter and a maternal aunt. However, the pathogenicity of the mutation was confirmed by restriction fragment length polymorphism analysis of single muscle fibers, which revealed a significantly greater level of mutant mtDNA in cytochrome c oxidase negative over cytochrome c oxidase positive fibers.

Original languageEnglish
Pages (from-to)66-71
Number of pages6
JournalNeuromuscular Disorders
Volume9
Issue number2
DOIs
Publication statusPublished - Mar 1 1999

Keywords

  • Cytochrome c oxidase
  • Mitochondrial tRNA(Lys)
  • Ophthalmoplegia

ASJC Scopus subject areas

  • Clinical Neurology
  • Pediatrics, Perinatology, and Child Health
  • Developmental Neuroscience
  • Neurology

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