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

Ying Peng1, Roger Crumley, John M Ringman

  • 1Department of Pediatrics, University of California at Irvine, Orange, California 92868, USA.

Movement Disorders : Official Journal of the Movement Disorder Society
|June 5, 2003
PubMed

Insights

Spasmodic dysphonia, a focal dystonia, was observed in a patient with myoclonic epilepsy and ragged red fibers (MERRF) syndrome. Treatment with botulinum toxin effectively improved the patient's spasmodic dysphonia.

Area of Science:

  • Neurology
  • Genetics
  • Mitochondrial Diseases

Background:

  • Dystonia is associated with mitochondrial dysfunction.
  • Spasmodic dysphonia, a focal dystonia, has not been previously linked to mitochondrial diseases.
  • Myoclonic epilepsy and ragged red fibers (MERRF) syndrome is caused by a common mitochondrial DNA mutation.

Observation:

  • A patient presented with action myoclonus in the hands and arms.
  • This patient carried the A8344G mutation in the mitochondrial tRNA(Lys) gene, causative of MERRF syndrome.
  • The patient also exhibited spasmodic dysphonia.

Findings:

  • The patient's spasmodic dysphonia responded positively to intralaryngeal botulinum toxin treatment.
  • This case suggests a potential link between MERRF syndrome and spasmodic dysphonia.
  • Mitochondrial dysfunction may contribute to focal dystonias like spasmodic dysphonia.

Implications:

  • This finding expands the clinical spectrum of MERRF syndrome.
  • It highlights the potential role of mitochondrial dysfunction in the pathophysiology of spasmodic dysphonia.
  • Botulinum toxin is a viable treatment option for spasmodic dysphonia in patients with MERRF syndrome.

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