John Libbey Eurotext

Epileptic Disorders

The Educational Journal of the International League Against Epilepsy

Myoclonus epilepsy in mitochondrial disorders Volume 18, supplément 2, September 2016

Illustrations

  • Figure 1
  • Figure 2
Auteurs
1 Unit of Molecular Neurogenetics, The Carlo Besta Institute of Neurology, Milan, Italy
2 MRC-Mitochondrial Biology Unit, Cambridge, United Kingdom
* Correspondence: Massimo Zeviani MRC-Mitochondrial Biology Unit, Cambridge, United Kingdom
  • Mots-clés : MERRF, MELAS, Alpers-Huttenlocher syndrome, hepatopathic poliodystrophy, mitochondrial DNA, oxidative phosphorylation, mitochondrial respiratory chain, progressive myoclonus epilepsies
  • DOI : 10.1684/epd.2016.0846
  • Page(s) : 94-102
  • Année de parution : 2016

Mitochondrial disorders is a group of clinical entities associated with abnormalities of the mitochondrial respiratory chain (MRC), which carries out the oxidative phosphorylation (OXPHOS) of ADP into ATP. As the MRC is the result of genetic complementation between two separate genomes, nuclear and mitochondrial, OXPHOS failure can derive from mutations in either nuclear-encoded, or mitochondrial-encoded, genes. Epilepsy is a relatively common feature of mitochondrial disease, especially in early-onset encephalopathies of infants and children. However, the two most common entities associated with epilepsy include MERRF, for Myoclonic Epilepsy with Ragged Red Fibers, and AHS, or Alpers-Huttenlocher syndrome, also known as hepatopathic poliodystrophy. Whilst MERRF is a maternally inherited condition caused by mtDNA mutations, particularly the 8344A>G substitution in the gene encoding mt-tRNALys, AHS is typically caused by recessive mutations in POLG, encoding the catalytic subunit of polymerase gamma, the only mtDNA polymerase in humans. AHS is the most severe, early-onset, invariably fatal syndrome within a disease spectrum, which also include other epileptogenic entities, all due to POLG mutations and including Spino-cerebellar Ataxia and Epilepsy (SCAE). This review reports the main clinical, neuroimaging, biochemical, and molecular features of epilepsy-related mitochondrial syndrome, particularly MERRF and AHS.