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Brain & Nervous System Health Center

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Ataxia Telangiectasia

It is possible that the main title of the report Ataxia Telangiectasia is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.


  • AT
  • Cerebello-Oculocutaneous Telangiectasia
  • Immunodeficiency with Ataxia Telangiectasia
  • Louis-Bar Syndrome

Disorder Subdivisions

  • None

General Discussion

Ataxia telangiectasia (AT) is a complex genetic neurodegenerative disorder that may become apparent during infancy or early childhood. The disorder is characterized by progressively impaired coordination of voluntary movements (ataxia), the development of reddish lesions of the skin and mucous membranes due to permanent widening of groups of blood vessels (telangiectasia), and impaired functioning of the immune system (i.e., cellular and humoral immunodeficiency), resulting in increased susceptibility to upper and lower respiratory infections (sinopulmonary infections). Individuals with AT also have an increased risk of developing certain malignancies, particularly of the lymphatic system (lymphomas), the blood-forming organs (e.g., leukemia), and the brain.

In those with AT, progressive ataxia typically develops during infancy and may initially be characterized by abnormal swaying of the head and trunk. As the disease progresses, the condition leads to an inability to walk (ambulation) by late childhood or adolescence. Ataxia is often accompanied by difficulty speaking (dysarthria), drooling; and an impaired ability to coordinate certain eye movements (oculomotor apraxia), including the occurrence of involuntary, rapid, rhythmic motions (oscillations) of the eyes while attempting to focus upon certain objects (fixation nystagmus). Affected children may also develop an unusually stooped posture and irregular, rapid, jerky movements that may occur in association with relatively slow, writhing motions (choreoathetosis). In addition, telangiectasias may develop by mid-childhood, often appearing on sun-exposed areas of the skin, such as the bridge of the nose, the ears, and certain regions of the extremities, as well as the mucous membranes of the eyes (conjunctiva).

AT is inherited as an autosomal recessive trait. The disorder is caused by changes (mutations) of a gene known as ATM (for "AT mutated") that has been mapped to the long arm (q) of chromosome 11 (11q22.3). The ATM gene controls (encodes for) the production of an enzyme that plays a role in regulating cell division following DNA damage.


March of Dimes Birth Defects Foundation
1275 Mamaroneck Avenue
White Plains, NY 10605
Tel: (914)997-4488
Fax: (914)997-4763
Tel: (888)663-4637

National Ataxia Foundation
2600 Fernbrook Lane Suite 119
Minneapolis, MN 55447
Tel: (763)553-0020
Fax: (763)553-0167

A-T Children's Project (Ataxia Telangiectasia Children's Project)
5300 W. Hillsboro Blvd. #105
Coconut Creek, FL 33073
Tel: (954)481-6611
Fax: (954)725-1153
Tel: (800)543-5728

American Cancer Society, Inc.
250 Williams NW St
Ste 6000
Atlanta, GA 30303
Tel: (404)320-3333
Tel: (800)227-2345
TDD: (866)228-4327

American Diabetes Association
1701 N. Beauregard Street
Alexandria, VA 22311
Tel: (703)549-1500
Fax: (703)549-6995
Tel: (800)342-2383

NIH/National Institute of Neurological Disorders and Stroke
P.O. Box 5801
Bethesda, MD 20824
Tel: (301)496-5751
Fax: (301)402-2186
Tel: (800)352-9424
TDD: (301)468-5981

Canadian Association for Familial Ataxias - Claude St-Jean Foundation
3800 Radisson Street Office 110
Quebec, H1M 1X6
Tel: 5143218684
Tel: 8553218684

Genetic and Rare Diseases (GARD) Information Center
PO Box 8126
Gaithersburg, MD 20898-8126
Tel: (301)251-4925
Fax: (301)251-4911
Tel: (888)205-2311
TDD: (888)205-3223

Movement Disorder Society
555 E. Wells Street
Suite 1100
Milwaukee, WI 53202-3823
Tel: (414)276-2145
Fax: (414)276-3349

For a Complete Report:

This is an abstract of a report from the National Organization for Rare Disorders (NORD). A copy of the complete report can be downloaded free from the NORD website for registered users. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational therapies (if available), and references from medical literature. For a full-text version of this topic, go to and click on Rare Disease Database under "Rare Disease Information".

The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only. NORD recommends that affected individuals seek the advice or counsel of their own personal physicians.

It is possible that the title of this topic is not the name you selected. Please check the Synonyms listing to find the alternate name(s) and Disorder Subdivision(s) covered by this report

This disease entry is based upon medical information available through the date at the end of the topic. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder.

For additional information and assistance about rare disorders, please contact the National Organization for Rare Disorders at P.O. Box 1968, Danbury, CT 06813-1968; phone (203) 744-0100; web site or email

Last Updated: 8/17/2007
Copyright 1987, 1990, 1992, 1996, 1997, 1998, 1999, 2000, 2004, 2007 National Organization for Rare Disorders, Inc.

WebMD Medical Reference from the National Organization for Rare Disorders

Last Updated: May 28, 2015
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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