Ataxia-Telangiectasia

Overview

Ataxia-telangiectasia (A-T) is a rare inherited disorder that affects several body systems, most notably the nervous system and the immune system. Its name comes from two of its main features: ataxia, meaning a loss of muscle coordination, and telangiectasia, meaning tiny clusters of widened blood vessels that appear most visibly in the whites of the eyes and on the skin.

Symptoms usually begin in early childhood, often when a child starts to walk. Over time, coordination worsens, and many children eventually need a wheelchair. People with A-T are also more prone to infections and have a higher risk of certain cancers. The disorder is caused by changes in a single gene and is passed down in families.

Symptoms

Symptoms appear gradually and progress over time:

• Ataxia: Unsteady walking, balance problems, and clumsiness, often the first sign in toddlers.
• Telangiectasia: Small, red, spidery clusters of blood vessels in the whites of the eyes and on the skin, usually appearing later in childhood.
• Slurred speech and difficulty with fine movements such as writing.
• Abnormal eye movements that make it hard to track objects.
• Frequent infections, especially of the lungs and sinuses.
• Delayed growth and, in some, slowed physical development.

Causes

Ataxia-telangiectasia is caused by changes (mutations) in a gene that makes a protein involved in repairing damaged DNA and coordinating the cell's response to such damage. When this protein does not work, cells cannot repair certain DNA damage properly, which affects the nervous system, the immune system, and the body's ability to control cell growth, contributing to the higher cancer risk.

A-T is inherited in an autosomal recessive pattern, so a child must inherit a changed copy of the gene from each parent to be affected. Carrier parents usually have no symptoms.

Risk Factors

• Having two parents who each carry a changed copy of the responsible gene
• A family history of the condition
• The disorder occurs in all populations

Diagnosis

Diagnosis combines clinical features with laboratory and genetic testing:

• Clinical evaluation: Recognizing progressive ataxia in early childhood together with telangiectasias.
• Blood tests: Certain markers, including a protein that is often elevated, and immune system measurements.
• Genetic testing: Identifying changes in the responsible gene confirms the diagnosis.
• Imaging: Brain MRI may show changes in the cerebellum, the part of the brain that controls coordination.

Treatment

There is no cure, so treatment focuses on supporting function and managing complications:

• Physical, occupational, and speech therapy to maintain mobility, daily skills, and communication.
• Treating and preventing infections, sometimes with antibiotics or, in selected cases, immune support.
• Cancer surveillance and careful treatment, because people with A-T are sensitive to radiation, which is generally avoided or minimized.
• Supportive devices such as wheelchairs as coordination declines.

Care is usually provided by a team of specialists, and genetic counseling helps families understand inheritance.

Prevention

Because A-T is inherited, it cannot be prevented. However:

• Genetic counseling helps families understand the chance of having an affected child
• Regular monitoring allows early treatment of infections and early detection of cancer
• Avoiding unnecessary radiation, including some X-rays, is important due to radiation sensitivity
• Up-to-date vaccinations and prompt care for infections help protect the lungs

When to See a Doctor

See a doctor if a young child has progressively worsening balance and coordination, slurred speech, or frequent infections, particularly if combined with red, spidery blood vessels in the eyes or on the skin. People with a diagnosis need ongoing specialist care, and any new persistent symptoms, especially signs of infection or unexplained illness, should be evaluated promptly.

Related Topics

Frequently Asked Questions

References

1. National Institute of Neurological Disorders and Stroke (NINDS). Ataxia Telangiectasia.
2. MedlinePlus Genetics, U.S. National Library of Medicine. Ataxia-telangiectasia.
3. Genetic and Rare Diseases Information Center (GARD). Ataxia telangiectasia.