Uneven distribution of mitochondrial DNA mutation in MERRF dizygotic twins

J Neurol Sci. 1992 Jul;110(1-2):144-8. doi: 10.1016/0022-510x(92)90021-c.


A new family of myoclonic epilepsy with ragged-red fibers (MERRF) was studied at clinical, histological, biochemical and molecular genetic levels. There was a remarkable variation in the age of onset, the clinical presentation and the severity of symptoms. Multiple defects affecting respiratory chain complexes I, III and IV were detected in 2 patients. The point mutation at 8344 of the mitochondrial genome was found in all the maternal lineage with a relatively narrow range of variation in the percentage of mutant mitochondrial genomes. The one exception was represented by a set of dizygotic twins, one clinically affected and showing high proportions of mutant mitochondrial DNAs (mtDNAs) in blood cells, while the other was asymptomatic and showed very small amounts of mutant mt-DNAs in blood and skin. This could suggest an early segregation of the mitochondrial genome during ovogenesis.

Publication types

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

MeSH terms

  • Adult
  • Base Sequence
  • Cytochromes / metabolism
  • DNA, Mitochondrial / genetics*
  • Diseases in Twins / genetics*
  • Electron Transport Complex II
  • Electron Transport Complex III / metabolism
  • Electron Transport Complex IV / metabolism
  • Epilepsies, Myoclonic / enzymology
  • Epilepsies, Myoclonic / genetics*
  • Epilepsies, Myoclonic / pathology
  • Female
  • Humans
  • Infant
  • Male
  • Mitochondria, Muscle / enzymology*
  • Molecular Sequence Data
  • Multienzyme Complexes / metabolism
  • Mutation*
  • NAD(P)H Dehydrogenase (Quinone) / metabolism
  • Oligodeoxyribonucleotides
  • Oxidoreductases / metabolism
  • Pedigree
  • Polymerase Chain Reaction / methods
  • Succinate Dehydrogenase / metabolism
  • Sural Nerve / pathology
  • Twins, Dizygotic*


  • Cytochromes
  • DNA, Mitochondrial
  • Multienzyme Complexes
  • Oligodeoxyribonucleotides
  • Oxidoreductases
  • Electron Transport Complex II
  • Succinate Dehydrogenase
  • NAD(P)H Dehydrogenase (Quinone)
  • Electron Transport Complex IV
  • Electron Transport Complex III