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APTX gene


Normal Function

The APTX gene provides instructions for making a protein called aprataxin that is involved in the repair of DNA damage in cells. Aprataxin is located in the nucleus of cells and is produced in various tissues, including the brain, spinal cord, and muscles. Different parts of the aprataxin protein allow the protein to interact with other DNA repair proteins to make repairs. At the site of the damage, aprataxin modifies the broken ends of the DNA strands so they can be joined back together correctly.

Health Conditions Related to Genetic Changes

Ataxia with oculomotor apraxia

More than 30 mutations in the APTX gene have been found to cause ataxia with oculomotor apraxia type 1. This condition is characterized by difficulty coordinating movements (ataxia) and problems with side-to-side movements of the eyes (oculomotor apraxia). Most mutations change single protein building blocks (amino acids) in aprataxin, resulting in an unstable aprataxin protein that is quickly broken down in the cell. A lack of functional aprataxin disrupts DNA repair and can lead to an accumulation of damage in cells, particularly affecting cells in the part of the brain involved in coordinating movements (the cerebellum). This accumulation can lead to cell death in the cerebellum, causing the characteristic movement problems of ataxia with oculomotor apraxia type 1.

More About This Health Condition

Other Names for This Gene

  • AOA
  • AOA1
  • ataxia 1, early onset with hypoalbuminemia
  • AXA1
  • EAOH

Additional Information & Resources

Tests Listed in the Genetic Testing Registry

Scientific Articles on PubMed

Catalog of Genes and Diseases from OMIM

Gene and Variant Databases


  • Ahel I, Rass U, El-Khamisy SF, Katyal S, Clements PM, McKinnon PJ, Caldecott KW, West SC. The neurodegenerative disease protein aprataxin resolves abortive DNA ligation intermediates. Nature. 2006 Oct 12;443(7112):713-6. doi: 10.1038/nature05164. Epub 2006 Sep 10. Citation on PubMed
  • Hirano M, Asai H, Kiriyama T, Furiya Y, Iwamoto T, Nishiwaki T, Yamamoto A, Mori T, Ueno S. Short half-lives of ataxia-associated aprataxin proteins in neuronal cells. Neurosci Lett. 2007 May 29;419(2):184-7. doi: 10.1016/j.neulet.2007.04.044. Epub 2007 Apr 25. Citation on PubMed
  • Le Ber I, Moreira MC, Rivaud-Pechoux S, Chamayou C, Ochsner F, Kuntzer T, Tardieu M, Said G, Habert MO, Demarquay G, Tannier C, Beis JM, Brice A, Koenig M, Durr A. Cerebellar ataxia with oculomotor apraxia type 1: clinical and genetic studies. Brain. 2003 Dec;126(Pt 12):2761-72. doi: 10.1093/brain/awg283. Epub 2003 Sep 23. Citation on PubMed
  • Rass U, Ahel I, West SC. Actions of aprataxin in multiple DNA repair pathways. J Biol Chem. 2007 Mar 30;282(13):9469-9474. doi: 10.1074/jbc.M611489200. Epub 2007 Feb 2. Citation on PubMed
  • Tada M, Yokoseki A, Sato T, Makifuchi T, Onodera O. Early-onset ataxia with ocular motor apraxia and hypoalbuminemia/ataxia with oculomotor apraxia 1. Adv Exp Med Biol. 2010;685:21-33. doi: 10.1007/978-1-4419-6448-9_3. Citation on PubMed
  • Takahashi T, Tada M, Igarashi S, Koyama A, Date H, Yokoseki A, Shiga A, Yoshida Y, Tsuji S, Nishizawa M, Onodera O. Aprataxin, causative gene product for EAOH/AOA1, repairs DNA single-strand breaks with damaged 3'-phosphate and 3'-phosphoglycolate ends. Nucleic Acids Res. 2007;35(11):3797-809. doi: 10.1093/nar/gkm158. Epub 2007 May 22. Citation on PubMed or Free article on PubMed Central
  • Tumbale P, Williams JS, Schellenberg MJ, Kunkel TA, Williams RS. Aprataxin resolves adenylated RNA-DNA junctions to maintain genome integrity. Nature. 2014 Feb 6;506(7486):111-5. doi: 10.1038/nature12824. Epub 2013 Dec 22. Citation on PubMed or Free article on PubMed Central

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