ATAXIA TELANGIECTASIA

Ataxia Telangiectasia (AT) is a rare, inherited childhood neurological disorder that causes degeneration in the part of the brain that controls motor movements and speech.

AT is caused by a mutation in the gene known as ATM (ataxia-telangiectasia, mutated). ATM makes a protein that regulates the cell cycle, DNA repair, and cell death. When this gene is defective, cells are unable to activate the cellular checkpoints that protect against the damage of ionizing radiation and other agents that can harm DNA.

The disease usually manifests in the first decade of life. Early symptoms include delayed development of motor skills, poor balance, and slurred speech, usually occurring during the first decade of life. In most instances, AT has little or no effect on intellectual development. It affects male and female children with equal frequency.

Ataxic features are progressive and ultimately result in inability to walk. Tiny, red "spider" veins known as Telangiectasias may develop, appearing in the corners of the eyes and on the surface of the ears and cheeks. Individuals with AT are acutely sensitive to ionizing radiation, such as X-rays or gamma-rays.

People with AT are unusually susceptible to developing cancer, most frequently acute lymphocytic leukemia or lymphoma. Many with AT have a weakened immune system and are vulnerable to recurrent respiratory infections.

Diagnostic testing: A physical exam revealing symptomology of the disease, laboratory testing including Alpha fetoprotein, B and t cell screen, carcinoembronic antigen, genetic testing for ATM gene, glucose tolerance testing, serum immunoglobulin levels, and x-rays of the thymus gland to determine the size of the gland.

Physical findings: Physical symptoms include:

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  Impaired growth;

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  Muscle weakness;

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  Repetitive bobbing, swaying, and jerking movements;

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  Drooling;

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  Inability to coordinate eye movements (oculomotor apraxia);

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  Small red spider veins (telangiectasias) in the eyes and on the face;

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  Difficulty swallowing; and

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  Premature graying of hair.

ICD-9: 334.8

ICD-10: G11.3

The prognosis for people with AT is poor. Survival past early adulthood is rare.

Complications that can arise from AT include:

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  Lymphoma (cancerous tumors that are in the lymph nodes);

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  Diabetes;

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  Kyphosis (abnormal curvature of the spine) leading to inability to walk;

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  Diabetes;

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  Scoliosis; and

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  Severe, recurrent lung infections.

There is no cure for AT, and currently no means of slowing the progression of the disease. Treatment is symptomatic and supportive. Physical and occupational therapy may help maintain flexibility. Speech therapy may also be needed. Gamma-globulin injections may help supplement the immune system. High-dose vitamin regimens may also be used.

Suggested MER for Evaluation: If sequence analysis of the ATM gene has identified mutations in both alleles in the proband, then the diagnosis of AT is confirmed. If this is unavailable, then a complete review of the clinical course, findings, and the available laboratory studies on which the disorder is suspected will be needed. Once the diagnosis is confirmed, a review of the current examination will be needed to establish severity, as variability in this disorder, although rare, has been reported.

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