Ataxia-Telangiectasia

Ataxia-Telangiectasia (Louis-Bar Syndrome)

An autosomal recessive condition characterized by progressive cerebellar ataxia, oculocutaneous telangiectasia, and immunodeficiency.

• Gene: ATM gene (Chromosome instability/defect in DNA repair).

Clinical Features

1. Neurological

• Progressive Cerebellar Ataxia: The first symptom to appear (usually 2nd or 3rd year of life).
• Choreoathetosis.

2. Cutaneous

• Telangiectasia: Appear between age 3–7 years.
• Classically found on the bulbar conjunctiva, ears, neck, and antecubital fossa.

3. Immunological

• Recurrent Infections: Sinopulmonary (sinus, lungs, bronchiectasis). Frequent cause of death.
• Immunodeficiency: Impairment of both cellular (thymic hypoplasia) and humoral immunity.
  • Low IgA (typically), IgG, and IgE.

4. Malignancy Risk

• High risk of developing malignancy, particularly lymphoma.

5. Radiation Sensitivity

• Cells are sensitive to irradiation; Ionizing radiation is Contraindicated.

Diagnosis

• Laboratory Findings:
  • ↑ Alpha-fetoprotein (AFP): Most characteristic/consistent abnormality.
  • ↑ Carcinoembryonic antigen (CEA).
  • ↓ IgA, IgG, IgE.

Management

• No specific treatment.
• Multidisciplinary team.
• Infection Management: IV immunoglobulin therapy and infection prophylaxis.
• Avoid radiation.

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