A novel mutation in the mitochondrial DNA tRNA Leu (UUR) gene associated with late-onset ocular myopathy

Neuromuscul Disord. 2007 May;17(5):415-8. doi: 10.1016/j.nmd.2007.01.015. Epub 2007 Mar 23.


We identified a novel G3283A transition in the mitochondrial DNA tRNA(Leu (UUR)) gene in a patient with ptosis, ophthalmoparesis and hyporeflexia. Muscle biopsy showed cytochrome oxidase positive ragged-red fibers, and defects of complexes I, III and IV of the mitochondrial respiratory chain. The mutation was heteroplasmic in muscle of the proband, being absent in her blood. Ragged-red fibers harbored greater levels of mutant genomes than normal fibers. The G3283A mutation affects a strictly conserved base pair in the TPsiC stem of the gene and was not found in controls, thus satisfying the accepted criteria for pathogenicity.

Publication types

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

MeSH terms

  • Aged, 80 and over
  • DNA Mutational Analysis / methods
  • DNA, Mitochondrial / genetics*
  • Female
  • Humans
  • Muscle, Skeletal / chemistry
  • Muscle, Skeletal / metabolism
  • Mutation*
  • Ophthalmoplegia, Chronic Progressive External / genetics*
  • Ophthalmoplegia, Chronic Progressive External / pathology
  • RNA, Transfer, Leu / genetics*


  • DNA, Mitochondrial
  • RNA, Transfer, Leu