AT (ataxia telangectasia)

Last reviewed 01/2018

Ataxia Telangiectasia (AT), which is another autosomal recessive cerebellar ataxia

  • incidence of 1:40,000–1:100,000 worldwide
  • characterized by the onset of truncal ataxia at the time of walking
    • ataxic syndrome is progressive and involves slurred speech and oculomotor abnormalities
    • typically a child affected by this condition is wheelchair bound by the age of 10 or 11 years of age
    • dystonia and chorea may also be part of the movement abnormalities
    • characteristic feature of the disease is the presence of telangiectasia, typically present on the conjunctivae or the skin of the face and ears

Considerable phenotypic variations have been observed in AT patients (2):

  • main variations are in age of onset of the ataxia, level of immunodeficiency, level of cellular radiosensitivity, and presence or absence of tumors
  • heterozygotes are clinically unaffected, but there are several reports indicating that they are prone to develop cancer, diabetes, and cardiovascular diseases (2)


  1. Furtado S et al. A review of the inherited ataxias: recent advances in genetic, clinical and neuropathologic aspects. Parkinsonism & Related Disorders; 4 (4):161-169.
  2. Laake L et al. Characterization of ATM mutations in 41 Nordic families with Ataxia Telangiectasia Human Mutation Volume 16, Issue 3, Date: September 2000, Pages: 232-246