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Ataxia telangiectasia (AT)—also known as Louis-Bar syndrome, cerebello-oculocutaneous telangiectasia, or immunodeficiency with ataxia telangiectasia—is a rare inherited childhood neurological disorder that affects the part of the brain that controls motor movement (intended movement of muscles) and speech. Ataxia telangiectasia also affects the spine and immune system. It usually begins in early childhood before age 5.

Ataxia telangiectasia is caused by mutations in the ATM (ataxia-telangiectasis mutated) gene. Some children with ataxia telangiectasia develop cancer, most frequently acute lymphocytic leukemia or lymphoma.

Neurological symptoms include:

  • Unsteady walking and lack of balance
  • Lack of coordination of movement
  • Slurred speech
  • Difficulty swallowing
  • Unintentional movement, such as tremor or jerky movement
  • Difficulty coordinating eye movement

Other symptoms may include:

  • Frequent respiratory infections
  • Red “spider” veins around the eyes, ears, or cheeks (telangiectasias)
  • Increased sensitivity to ionizing radiation (such as X-rays or gamma rays)
  • Diabetes
  • Premature graying of the hair
  • Fatigue
  • Delayed physical and sexual development

There is no cure for ataxia telangiectasia and, currently, no way to slow the progression. Treatment is symptomatic and supportive, such as physical therapy to help maintain flexibility and speech therapy to teach children how to control breathing. Additionally, high-dose vitamins, antioxidants, and gamma-globulin injections may be useful. The severity of the ATM mutation adjusts the average lifespan. Those who had a later onset and slower progression of ataxia telangiectasia typically survive into their 50s.

How can I or my loved one help improve care for people with ataxia telangiectasis?

Consider participating in a clinical trial so clinicians and scientists can learn more about ataxia telangiectasia and related disorders. Clinical research uses human volunteers to help researchers learn more about a disorder and perhaps find better ways to safely detect, treat, or prevent disease.

All types of volunteers are needed—those who are healthy or may have an illness or disease—of all different ages, sexes, races, and ethnicities to ensure that study results apply to as many people as possible, and that treatments will be safe and effective for everyone who will use them.

For information about participating in clinical research visit NIH Clinical Research Trials and You. Learn about clinical trials currently looking for people with ataxia telangiectasia at

Where can I find more information about ataxia telangiectasia?

Information is available from the following resources:



National Ataxia Foundation
Phone: 763-553-0020

This information was developed by the National Institute of Neurological Disorders and Stroke.

National Institute of Neurological Disorders and Stroket. NINDS Ataxia Telangiectasia Information Page. Available at: Accessed July 11, 2023.

The information in this document is for general educational purposes only. It is not intended to substitute for personalized professional advice. Although the information was obtained from sources believed to be reliable, MedLink LLC, its representatives, and the providers of the information do not guarantee its accuracy and disclaim responsibility for adverse consequences resulting from its use. For further information, consult a physician and the organization referred to herein.

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