Ataxia-telangiectasia

Ataxia-telangiectasia is a rare inherited disorder of childhood that affects the nervous system, immune system, and other body systems.

This disorder is characterized by progressive difficulty with coordinating movements (ataxia) beginning in early childhood. Affected children typically develop difficulty walking, problems with balance, abnormal eye movements, and slurred speech. Small clusters of enlarged blood vessels called telangiectases, which occur in the eyes and on the surface of the skin, are also characteristic of this condition.

People with ataxia-telangiectasia often have weakened immune systems, and many develop chronic lung infections. They are also at an increased risk of developing cancer, particularly cancer of blood-forming tissue (leukemia) and cancer of immune system cells (lymphoma). Affected individuals are very sensitive to the effects of radiation exposure, including medical x-rays. Although people with ataxia-telangiectasia usually live into adulthood, their life expectancy is reduced.

How common is ataxia-telangiectasia?

This condition occurs in 1 in 40,000 to 100,000 people worldwide.

What genes are related to ataxia-telangiectasia?

Mutations in the ATM gene cause ataxia-telangiectasia.

The ATM gene provides instructions for making a protein that helps control cell division and is involved in DNA repair. This protein plays an important role in the normal development and activity of several body systems, including the nervous system and immune system. Mutations in the ATM gene reduce or eliminate the function of the ATM protein. Without this protein, cells in the brain die inappropriately, particularly in a part of the brain involved in coordinating movements (the cerebellum). The loss of these brain cells causes the movement problems characteristic of this disorder. Mutations in the ATM gene also prevent cells from responding correctly to DNA damage, which allows genetic defects to accumulate and can lead to cancer.

Read more about the ATM gene.

How do people inherit ataxia-telangiectasia?

Ataxia-telangiectasia is inherited in an autosomal recessive pattern, which means both copies of the ATM gene in each cell have mutations. Most often, the parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but do not show signs and symptoms of the condition.

About 1 percent of the United States population (2.5 million people) carry one mutated copy and one normal copy of the ATM gene. Although they do not have ataxia-telangiectasia, they are more likely than people without an ATM mutation to develop cancer, particularly breast cancer. Carriers of a mutation in the ATM gene also may have an increased risk of heart disease.

What other names do people use for ataxia-telangiectasia?

• A-T
• Ataxia Telangiectasia Syndrome
• ATM
• Louis-Bar syndrome
• Telangiectasia, cerebello-oculocutaneous

Where can I find information about treatment for ataxia-telangiectasia?

These resources address the management of ataxia-telangiectasia and may include treatment providers.

• Gene Review
• MedlinePlus Encyclopedia: Ataxia-telangiectasia

You might also find information on treatment of ataxia-telangiectasia in Educational resources and Patient support.

Where can I find additional information about ataxia-telangiectasia?

You may find the following resources about ataxia-telangiectasia helpful. These materials are written for the general public.

• MedlinePlus - Health information (2 links)
• Additional NIH Resources - National Institutes of Health (4 links)
• Educational resources - Information pages (5 links)
• Patient support - For patients and families (7 links)

You may also be interested in these resources, which are designed for healthcare professionals and researchers.

• Gene Reviews - Clinical summary
• Gene Tests - DNA tests ordered by healthcare professionals
• ClinicalTrials.gov - Linking patients to medical research
• PubMed - Recent literature
• OMIM - Genetic disorder catalog

See How are genetic conditions and genes named? in the Handbook.

What if I still have specific questions about ataxia-telangiectasia?

• See How can I find a genetics professional in my area? in the Handbook.
• Ask the Genetic and Rare Diseases Information Center.
• Submit your question to Ask the Geneticist.

Where can I find general information about genetic conditions?

The Handbook provides basic information about genetics in clear language.

• What does it mean if a disorder seems to run in my family?
• What are the different ways in which a genetic condition can be inherited?
• If a genetic disorder runs in my family, what are the chances that my children will have the condition?
• Why are some genetic conditions more common in particular ethnic groups?

These links provide additional genetics resources that may be useful.

• Genetics and health
• Resources for Patients and Families
• Resources for Health Professionals

What glossary definitions help with understanding ataxia-telangiectasia?

ataxia ; autosomal ; autosomal recessive ; cancer ; carrier ; cell ; cell division ; cerebellum ; chronic ; DNA ; DNA damage ; DNA repair ; gene ; immune system ; infection ; leukemia ; lymphoma ; mutation ; nervous system ; population ; protein ; radiation ; recessive ; sign ; symptom ; syndrome ; telangiectasia ; telangiectasis ; tissue ; x-rays

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.