A novel nonsense mutation in a Japanese family with ataxia with oculomotor apraxia type 2 (AOA2)

J Hum Genet. 2009 Dec;54(12):746-8. doi: 10.1038/jhg.2009.104. Epub 2009 Nov 6.


We report a 67-year-old Japanese woman with ataxia with oculomotor apraxia type 2 (AOA2). She was born to consanguineous parents and showed a teenage onset, a slowly progressive cerebellar ataxia and sensory-motor neuropathy and an elevated level of serum alpha-fetoprotein (AFP). All of these clinical features were consistent with typical AOA2. She lacked oculomotor apraxia, as frequently observed in previously reported AOA2 patients. She was homozygous for a novel nonsense mutation, Glu385Ter (E385X), in the senataxin gene (SETX). To our knowledge, this is the fifth Japanese family with genetically confirmed AOA2. The mutations in SETX in Japanese AOA2 families are heterogeneous, except for M274I, which has been found in two unrelated families. More extensive screening by serum AFP followed by molecular genetic analysis of SETX in patients with Friedreich's ataxia-like phenotype may show that AOA2 is more common in Japan than previously thought.

Publication types

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

MeSH terms

  • Aged
  • Apraxias / complications
  • Apraxias / genetics*
  • Ataxia / complications
  • Ataxia / genetics*
  • Codon, Nonsense*
  • Consanguinity
  • DNA Helicases
  • Family Health
  • Female
  • Humans
  • Japan
  • Male
  • Multifunctional Enzymes
  • Ocular Motility Disorders / complications
  • Ocular Motility Disorders / genetics*
  • RNA Helicases / genetics*


  • Codon, Nonsense
  • Multifunctional Enzymes
  • SETX protein, human
  • DNA Helicases
  • RNA Helicases