What is ataxia telangiectasia?

Ataxia-telangiectasia (A-T), also known as Louis-Bar syndrome, is a rare hereditary disease that leads to neurological symptoms, with increasing loss of muscle control and balance disorders even during early childhood. Typical skin changes (telangiectasia = dilation of the small cutaneous vessels) are found in the conjunctiva of the eye and particularly in areas of skin exposed to light. There is an increased likelihood that cancerous diseases and infections will occur.

How is ataxia telangiectasia diagnosed?

Clinical Presentation

Patients with ataxia-telangiectasia exhibit certain common clinical symptoms, including typical A-T:

  • Developmental delay with a movement coordination and balance disorder, starting between the ages of 1 and 4

  • Dilation of the vessels in the conjunctiva of the eye and areas of skin exposed to light

  • A lack of target-focused eye movement

  • Sudden uncontrolled excessive and spontaneous movements, bent posture, tremors

  • Dementia

  • Immunodeficiency

  • Increased susceptibility to infections

In atypical A-T, a distinction is made between 2 different forms: One form starts in adulthood and the other with early-onset muscular tension.

Other common findings are premature aging, with the development of gray hair, and endocrine abnormalities, with the development of insulin-resistant diabetes and premature loss of ovarian function.

Confirming the Diagnosis

The diagnosis is suspected when the characteristic clinical signs are present and especially due to conjunctival telangiectasia. Testing for laboratory parameters produces indicative findings (an elevated level of alpha-fetoprotein (AFP) and of the carcinoembroyonic antigen (CEA) and a reduction in immunoglobulin levels). The suspicion is confirmed by molecular genetic testing.

What is the risk of cancer?

The risk of cancer in patients with typical A-T is 38% and is predominantly due to leukemia (acute lymphatic leukemia, especially of the T-cell line) and lymphoma (especially B-cell lymphomas).

In carriers (such as the parents), there is an increased risk of breast and ovarian cancer, stomach tumors, skin tumors, and tumors of the smooth muscles and connective tissue.

What causes ataxia telangiectasia?

The genetic change in the ATM gene (ataxia telangiectasia-mutated gene) leads to a faulty DNA repair signaling cascade, accompanied by genetic instability – particularly induced by ionizing radiation.

Is there a treatment?

Treatment of neoplasia associated with A-T mainly consists of diagnosing preliminary cancer stages as early as possible. The corresponding treatment recommendation is to have the study center handle treatment, with treatment intensity being adapted as needed whenever increased treatment toxicity arises.

Surveillance Recommendations for the Early Detection of Cancer

Surveillance Recommendations

Once ataxia-telangiectasia has been diagnosed, a thorough basic examination is recommended. Regular neurodevelopmental examinations and documenting infection frequencies are also recommended. Annual laboratory testing, an annual skin examination, annual diabetes testing, and annual orthopedic and six-monthly dental examinations should be performed as well.

Specifically, the following examinations are recommended:

  • Hemato-oncology: annual blood count, metabolic profile, including lactate dehydrogenase (LDH)

  • Immunology: determination of the immunoglobulin levels according to immunological recommendations

  • Dermatology: annual skin examination

  • Pulmonology: basic examination following the diagnosis, and function tests according to clinical necessity

  • Gastroenterology/Nutrition: basic examination following the diagnosis, and during progression, if there are clinical problems

  • Endocrinology: annual diabetes screening

  • Neurology: supporting medication

  • Orthopedics: annual examination (scoliosis)

  • Dental: six-monthly checkups