Respiration-deficient cells are caused by a single point mutation in the mitochondrial tRNA-Leu (UUR) gene in mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes (MELAS)

Am J Hum Genet. 1991 Sep;49(3):590-9.


MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes) is a major subgroup of heterogeneous mitochondrial diseases. For identifying a mutation in the mitochondrial gene, we isolated, from the same muscle tissue from a patient with MELAS, cell lines with distinctly different phenotypes: one was respiration-deficient, and the other was apparently normal. Compared with the normal cells, only one A-to-G nucleotide transition at nucleotide 3243 in the tRNA-Leu (UUR) gene was found in whole mtDNA of the respiration-deficient cells. This mutation was also found in eight patients, from unrelated families, who had MELAS in a heteroplasmic manner but was not found in control individuals. Therefore, the single point mutation causes the functional abnormality in the respiratory chain of mitochondria.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acidosis, Lactic / genetics
  • Asian Continental Ancestry Group
  • Base Sequence
  • Brain Diseases / genetics
  • Cell Line
  • Cerebrovascular Disorders / genetics
  • Child
  • DNA, Mitochondrial / genetics*
  • Female
  • Humans
  • Mitochondria / metabolism*
  • Molecular Sequence Data
  • Muscular Diseases / genetics
  • Mutation / genetics*
  • Nucleic Acid Conformation
  • RNA / genetics*
  • RNA, Mitochondrial
  • RNA, Transfer, Leu / genetics*
  • Sequence Alignment


  • DNA, Mitochondrial
  • RNA, Mitochondrial
  • RNA, Transfer, Leu
  • RNA

Associated data

  • GENBANK/M77181
  • GENBANK/S55816
  • GENBANK/S55822
  • GENBANK/S55853
  • GENBANK/S55854
  • GENBANK/S62061
  • GENBANK/S62063
  • GENBANK/S62066
  • GENBANK/S62712
  • GENBANK/S68604