An mtDNA mutation, 14453G-->A, in the NADH dehydrogenase subunit 6 associated with severe MELAS syndrome

Eur J Hum Genet. 2001 Oct;9(10):805-9. doi: 10.1038/sj.ejhg.5200712.


We report a novel point mutation in the gene for the mitochondrially encoded ND6 subunit of the NADH:ubiquinone oxidoreductase (complex I of the respiratory chain) in a patient with MELAS syndrome. The mutation causes a change from alanine to valine in the most conserved region of the ND6 subunit. The patient was heteroplasmic for the mutation in both muscle and blood, but the mutation was not detected in the patient's mother. A marked reduction of complex I activity was found in the patient's muscular tissue. This is the first report of a mutation in the ND6 subunit causing MELAS. Our data confirm the genetic heterogeneity in mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes syndrome, and confirms that MELAS can be caused by mutation in polypeptide-coding mtDNA genes.

Publication types

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

MeSH terms

  • Base Sequence
  • Child, Preschool
  • DNA Mutational Analysis
  • DNA, Mitochondrial / blood
  • DNA, Mitochondrial / genetics*
  • Female
  • Humans
  • MELAS Syndrome / blood
  • MELAS Syndrome / enzymology*
  • MELAS Syndrome / genetics*
  • Mitochondria, Muscle / enzymology
  • Mutation / genetics*
  • NADH Dehydrogenase / chemistry*
  • NADH Dehydrogenase / genetics*
  • NADH Dehydrogenase / metabolism
  • Protein Subunits
  • Restriction Mapping


  • DNA, Mitochondrial
  • Protein Subunits
  • NADH Dehydrogenase