Ataxia Telangiectasia

What is ataxia telangiectasia?

Ataxia-telangiectasia (A-T) is a rare, inherited disorder that affects the nervous system, immune system, and other parts of the body. It causes ataxia (problems with coordination and balance). A-T weakens the immune system and increases the risk of cancer. A-T is sometimes called Louis-Bar syndrome, named after the two doctors who first described the condition.

A-T is a neurodegenerative disorder that affects the part of the brain that controls balance and coordination, known as the cerebellum. In A-T, cells in this brain area gradually die over time. People with A-T usually develop symptoms in early childhood that get worse over time.

Changes (also called variants or mutations) in a gene called ATM causes A-T. While scientists are sure the ATM gene causes A-T, they’re unsure exactly how. One clue is that the ATM gene is important for repairing DNA damage through the ATM protein that the gene makes.

In healthy cells, DNA is regularly damaged when cells go about their normal work or from exposure to the environment—such as sunlight, radiation, pollution, or chemicals. Normally, cells can repair this damage. But in people with A-T, the ATM protein doesn’t work properly or at all. Their cells cannot repair DNA damage effectively, which can lead to cell death or abnormal cell growth. This increases risk for neurological disorders, problems with the immune system, and cancer.

Because the ATM protein helps cells fix DNA damaged by radiation damage, people with A-T are especially sensitive to medical radiation such as X-rays.

Symptoms

A-T causes many different symptoms, including ataxia, loss of control of coordination and balance. A-T symptoms caused by nerve damage include:

• Unsteady walking and problems with balance
• Lack of coordination
• Slurred or slow speech
• Difficulty swallowing
• Unintentional movements, such as tremors or jerky movements
• Problems moving the eyes 

A-T can also cause other symptoms, including:

The ATM gene variant a person with A-T has affects how severe their disease is and which symptoms they have.

For example, some people have ATM gene variants that don’t make any ATM protein at all. That means their bodies can’t repair damaged DNA, which can cause problems in many different body parts. People can develop severe symptoms in early childhood and the disease worsens quickly. Because this form of A-T can lead to serious complications, many of these people live into early adulthood.

Other people have milder forms of A-T because they have an ATM protein that works a little, but not fully. Because the symptoms are milder and develop slowly, the condition may not be recognized right away, and diagnosis can be delayed.

Who is more likely to get ataxia-telangiectasia?

A-T is inherited in an autosomal recessive pattern, and both females and males can get the condition. This means a person must inherit both copies of the abnormal gene variant, one from each parent, to have the disease. The parents of a person with an autosomal recessive condition each carry one copy of the altered gene, but they typically don’t show signs and symptoms of the condition.

People with family members with A-T are at a higher risk of having A-T or having a child with A-T. Genetic counseling can help people with family members with A-T understand the chances that they may have a child with A-T. Although A-T is rare, some groups of people are more likely to carry the ATM gene mutations that cause A-T.

People who inherit an ATM gene variant from only one parent don’t get A-T, but they may have a higher risk of cancer, especially breast cancer. Genetic counseling may help these people understand their cancer risk.

How is ataxia-telangiectasia diagnosed and treated?

Diagnosing A-T

Children with A-T are typically diagnosed early in life, since symptoms often develop before age 5. If a doctor thinks a person may have A-T, they may do tests to rule out other conditions that cause similar symptoms. These tests can suggest a person has A-T, but genetic testing to look for changes in the ATM gene is usually needed to confirm the diagnosis since all cases of A-T are inherited.

Learn more about neurological diagnostic tests and procedures.

Treating A-T

Currently, no treatments can cure A-T or keep the condition from getting worse. But doctors can treat many of its symptoms and help people manage the condition. This usually involves a team of healthcare professionals who work together to support people with A-T.

Physical therapy can help keep people with A-T stay flexible and move more easily. Wheelchairs and braces can help with walking, coordination, and balance. Occupational therapy can help with everyday tasks. Speech therapy and communication tools may help children with speech problems. Visual aids, such as special glasses, magnifiers, or large-print materials, may help people control eye movements.

People with A-T may get infections more often than other people since their immune system is weaker than normal. Preventing infections and treating them quickly are important parts of care. Some treatments—such as high-dose vitamins, antioxidants, and gamma-globulin—may help treat A-T symptoms.

Doctors also monitor people with A-T for diabetes and cancer. Because their cells are very sensitive to radiation, people with A-T usually don’t receive radiation therapy, and doctors try to limit tests that use radiation like X-rays or computed tomography (CT) scans.

What are the latest updates on ataxia-telangiectasia?

The National Institutes of Health (NIH), which includes NINDS, is the leading federal funder of research on the brain and nervous system, including disorders such as A-T. NIH supports new and innovative research to better understand, diagnose, and treat A-T.

Current NIH-funded research is exploring how A-T develops and how it might be treated. The scientists are using a special mouse model. These mice have A-T symptoms that look like those of people with A-T. Another NIH-funded study is looking at whether abnormal proteins collect in the brains of people with A-T and how this may be related to problems with the ATM protein. Other research is studying how the body manages DNA damage along with how the ATM protein is involved.

NIH-funded researchers are testing whether small motion-tracking devices worn on the body can predict how and when symptoms get worse in people with A-T. This approach may be able to measure coordination problems in people with A-T more precisely than standard clinical exams. Better tools to measure A-T symptoms will help researchers test new treatments.

NIH is also funding a program to create more places where people with A-T and other rare diseases can give blood samples for clinical trials, making it easier for more people to participate in this research that can lead to new treatments.

NIH-funded research is also studying how the brain controls balance and coordination and how cells repair DNA. This research can help lead to future treatments for conditions like A-T.

For more information on research about A-T, check NIH RePORTER, a searchable database of current and past research projects funded by NIH and other federal agencies. RePORTER also has links to publications and resources from these projects.

For research articles and summaries on A-T, search PubMed, which contains citations from medical journals and other sites.

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 A-T and related disorders. Clinical research with human study participants helps 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. This helps make sure 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 the NINDS Clinical Trials site and NIH Clinical Research Trials and You. Learn about clinical trials currently looking for people with A-T at ClinicalTrials.gov, a searchable database of current and past clinical studies and research results.

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