Novel heteroplasmic mutation in the anticodon stem of mitochondrial tRNA(Lys) associated with dystonia and stroke-like episodes

Acta Neurol Scand. 2010 Oct;122(4):252-6. doi: 10.1111/j.1600-0404.2009.01297.x. Epub 2009 Nov 20.


Objectives: We report a novel heteroplasmic mitochondrial tRNA(Lys) mutation associated with dystonia, stroke-like episodes, sensorineural hearing loss and epilepsy in a Hungarian family.

Material and methods: A 16-year-old boy, his brother and mother were investigated. Thorough clinical investigation as well as electrophysiological, neuroradiological and myopathological examinations were performed. Molecular studies included the analysis of the DYT1, DDP1/TIMM8A (deafness-dystonia peptid-1) genes and mitochondrial DNA (mtDNA).

Results: The mtDNA analysis of the proband revealed a heteroplasmic A8332G substitution in the anticodon stem of the tRNA(Lys) gene. The mutation segregated in all affected family members. Besides this mutation 16 further mtDNA polymorphisms were detected. Complex I activity of the patient's fibroblast cultures showed decreased activity confirming mitochondrial dysfunction.

Conclusion: The novel A8332G heteroplasmic mutation is most likely a new cause of dystonia and stroke-like episodes due to mitochondrial encephalopathy. The synergistic effect of the G8697A, A11812G and T10463C single nucleotide polymorphisms may modify the phenotype.

Publication types

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

MeSH terms

  • Adolescent
  • Anticodon / genetics*
  • Dystonia / genetics*
  • Epilepsy / genetics
  • Hearing Loss, Sensorineural / genetics
  • Humans
  • Hungary
  • Male
  • Mitochondria / genetics*
  • Mutation
  • Pedigree
  • Polymorphism, Genetic
  • RNA, Transfer / genetics*
  • Stroke / genetics*


  • Anticodon
  • RNA, Transfer