Spasmodic dysphonia in a patient with the A to G transition at nucleotide 8344 in mitochondrial DNA

Mov Disord. 2003 Jun;18(6):716-8. doi: 10.1002/mds.10428.


Dystonia has been described in various diseases affecting mitochondrial function but spasmodic dysphonia, a form of focal dystonia, has not. We present a patient with action myoclonus affecting the hands and arms who carried the most common mutation in mitochondrial DNA causing the myoclonic epilepsy and ragged red fibers (MERRF) syndrome (the A-->G substitution at nucleotide 8344 in the tRNA(Lys) gene). This patient also had spasmodic dysphonia that was responsive to treatment with intralaryngeal botulinum toxin.

Publication types

  • Case Reports
  • Lecture

MeSH terms

  • DNA, Mitochondrial / metabolism*
  • Epilepsies, Myoclonic / complications
  • Female
  • Humans
  • Middle Aged
  • Mitochondrial Diseases / complications*
  • Mitochondrial Diseases / genetics*
  • Mutation*
  • Myoclonus / complications
  • Pedigree
  • Statistics, Nonparametric
  • Voice Disorders / genetics*
  • Voice Disorders / metabolism*


  • DNA, Mitochondrial