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J Med Genet 44:797-799 doi:10.1136/jmg.2007.052902
  • Letters to JMG

Episodic ataxia and hemiplegia caused by the 8993T→C mitochondrial DNA mutation

  1. K Craig1,
  2. H R Elliott1,
  3. S M Keers1,
  4. C Lambert1,
  5. A Pyle1,
  6. T D Graves2,
  7. C Woodward2,
  8. M G Sweeney2,
  9. M B Davis2,
  10. M G Hanna2,
  11. P F Chinnery1,3
  1. 1
    Mitochondrial Research Group, Institute of Neurology, Queen Square, London, UK
  2. 2
    Department of Molecular Neuroscience, Institute of Neurology, Queen Square, London, UK
  3. 3
    Institute of Human Genetics, Newcastle University, UK
  1. Professor P F Chinnery, M41014, The Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK; p.f.chinnery{at}ncl.ac.uk
  • Received 5 July 2007
  • Revised 26 July 2007
  • Accepted 31 July 2007

Abstract

The m.8993T→C MTATP6 mutation of mitochondrial DNA (mtDNA) usually causes mitochondrial disease in childhood, but was recently described in a family with adult onset ataxia and polyneuropathy. Cytochrome c oxidase muscle histochemistry, which is the standard clinical investigation for mitochondrial disease in adults, is usually normal in patients with MTATP6 mutations. This raises the possibility that these cases have been missed in the past. We therefore studied 308 patients with unexplained ataxia and 96 patients with suspected Charcot–Marie–Tooth disease to determine whether the m.8993T→C MTATP6 mutation is common in unexplained inherited ataxia and/or polyneuropathy. We identified a three-generation family with the m.8993T→C mutation of mtDNA. One subject had episodic ataxia (EA) and transient hemipareses, broadening the phenotype. However, no further cases were identified in an additional cohort of 191 patients with suspected EA. In conclusion, m.8993T→C MTATP6 should be considered in patients with unexplained ataxia, CMT or EA, but cases are uncommon.

Footnotes

  • Competing interests: none declared.

  • Abbreviations:
    BSN
    bilateral striatal necrosis
    CMT
    Charcot–Marie–Tooth
    EA
    episodic ataxia
    EA2
    episodic ataxia type 2
    FHM
    familial hemiplegic migraine
    LS
    Leigh syndrome
    mtDNA
    mitochondrial DNA
    NARP
    neurogenic weakness with ataxia and retinitis pigmentosa