Published: 18 Jun 2025

ICD9: 334.8      ICD10: G11.3      ICD11: 4A01.31

Ataxia-telangiectasia (AT) is a rare, inherited genetic disorder that affects multiple body systems.
The name itself gives clues to some of the primary characteristics:

Ataxia: Refers to poor coordination and balance. This is a hallmark of the disease, and it typically manifests in early childhood.
Telangiectasia: Refers to small, widened blood vessels (spider veins) that can appear on the skin and in the eyes.

Key Features and Symptoms:

Here's a more detailed breakdown of the common features and symptoms associated with AT:

Neurological Problems:
Progressive cerebellar ataxia: Difficulty with coordination, balance, and walking. This is usually the first noticeable symptom, starting around 1-4 years of age.
Slurred speech
Slowed eye movements
Muscle weakness
Involuntary movements (e.g., chorea, myoclonus)

Immune Deficiency:
Increased susceptibility to infections, especially respiratory infections (sinusitis, pneumonia, bronchitis).
Low levels of certain immunoglobulins (antibodies) in the blood.
Impaired immune response to vaccinations.

Telangiectasias:
Most commonly appear in the corners of the eyes (conjunctival telangiectasias).
Can also occur on sun-exposed skin, such as the face, ears, and inside the elbows and knees.
These are usually not painful or itchy.

Increased Risk of Cancer:
Individuals with AT have a significantly higher risk of developing certain cancers, particularly leukemia and lymphoma.

Other Potential Features:
Delayed physical development.
Premature aging (e.g., graying hair).
Diabetes mellitus.
Difficulty swallowing.
Sensitivity to radiation (important to consider during medical imaging and cancer treatment).
Learning difficulties (though intelligence can be normal).

Cause:

AT is caused by mutations in the *ATM* gene (ataxia-telangiectasia mutated gene). This gene provides instructions for making a protein that plays a crucial role in:

DNA repair: The ATM protein helps repair damaged DNA, preventing the accumulation of mutations that can lead to cancer and other problems.
Cell cycle control: It helps regulate the cell cycle, preventing cells with damaged DNA from dividing uncontrollably.
Immune function: It is involved in the development and function of the immune system.

AT is inherited in an autosomal recessive pattern. This means that a person must inherit two copies of the mutated *ATM* gene (one from each parent) to develop the disorder. Individuals who inherit only one copy of the mutated gene are called carriers. They typically do not have symptoms of AT, but they can pass the gene on to their children.

Diagnosis:

Diagnosis typically involves a combination of:

Clinical evaluation: Assessing symptoms and physical signs.
Blood tests: To measure levels of immunoglobulins, alpha-fetoprotein (AFP, often elevated in AT), and to assess immune function.
Genetic testing: To identify mutations in the *ATM* gene.
Brain MRI: To look for characteristic abnormalities in the cerebellum.

Treatment:

There is no cure for AT, and treatment is focused on managing the symptoms and preventing complications:

Infections: Prompt treatment of infections with antibiotics. Some patients may benefit from immunoglobulin replacement therapy to boost their immune system.
Neurological problems: Physical therapy, occupational therapy, and speech therapy can help to improve coordination, balance, and communication skills. Medications may be used to manage involuntary movements.
Cancer: Careful monitoring for cancer is important. Treatment of cancer in individuals with AT can be challenging because they are particularly sensitive to the side effects of radiation and some chemotherapy drugs.
Nutritional support: To address swallowing difficulties and maintain adequate nutrition.

Prognosis:

The prognosis for individuals with AT varies. The disease is progressive, and most individuals will require significant support as they get older. Life expectancy is often shortened due to complications such as infections, cancer, and neurological problems. However, with good medical care and supportive therapies, many individuals with AT can live into their 30s or 40s or even longer.

Important Considerations:

Genetic counseling is important for families with a history of AT.
Individuals with AT should avoid unnecessary exposure to radiation.
Coordination of care among specialists is essential for optimal management.
Support groups and advocacy organizations can provide valuable resources and support for individuals with AT and their families.