Louis-Bar syndrome

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Alternative names
Ataxia - telangiectasia

Definition
Ataxia-telangiectasia is an inherited disorder that affects many tissues and systems in the body. Multiple symptoms may include telangiectasis (dilation of capillaries), ataxic (uncoordinated) gait, proneness to infection, defective humoral and cellular immunity and increased risk of malignancies.

Causes, incidence, and risk factors
Ataxia-telangiectasia is transmitted as an autosomal recessive trait. The disease results from mutations in a gene called ATM. The most obvious symptoms of the disease are multiple telangiectases that are easily visible in the white of the eye and skin areas such as the ear and nose, graying of the hair, and irregular pigmentation of the skin in areas exposed to sunlight. In addition, there is decreased coordination of movements (ataxia) in late childhood.

Symptoms

• Delayed walking
  
• Unsteady, jerky gait, ataxic gait (cerebellar ataxia)
  
• Dilated blood vessels in the whites of the eyes
  
• Dilated blood vessels in skin of nose, ears, and flexion side of the elbow and knee)
  
• Severe recurrent respiratory infections
  
• Decreasing mental development which slows or stops after age 10-12
  
• Movement disorder late in the disease
  
• Repetitive abnormal or jerky eye movements (nystagmus) late in the disease
  
• Coffee-with-milk colored spots of the skin
  
• Seizures

Signs and tests

• Mask-like face
  
• Decreased to absent deep tendon reflexes
  
• Multiple skin changes including pigmentary, eczematoid and atrophic
  
• Growth failure
  
• Absence of pubertal development
  
• Hypoplastic tonsils, lymph nodes, and spleen

Possible tests include:

• Serum immunoglobulin levels (IgE, IgA) - especially decreased IgA and IgE levels
  
• Decreased B and T cell screen
  
• Elevated alpha fetoprotein (AFP)
  
• Carcinoembryonic antigen (CEA)
  
• Increased tendency of chromosomes to break on exposure to radiation
  
• Genetic testing for mutations in the ATM gene.
  
• X-rays showing underdeveloped, small thymus in childhood
  
• Abnormal glucose tolerance test

Treatment
There is no specific treatment for ataxia-telangiectasia. Treatment is directed at specific associated problems.

Support Groups
Ataxia Telangiectasia Children’s Project
800-543-5728
http://www.atcp.org

Expectations (prognosis)
An early death is expected, commonly in early adolescence.

Complications

• Severe recurrent pulmonary infections
  
• Progressive movement disorder with confinement to a wheelchair
  
• Malignant disease, especially lymphoma, that can result in death
  
• Diabetes
  
• Progressive scoliosis and kyphosis

Calling your health care provider
Call your health care provider if signs or symptoms of the disease are present.

Prevention
Because these patients are very sensitive to radiation, they should never be exposed to radiation therapy and no unnecessary x-rays should be done. Genetic counseling is of benefit to prospective parents with a family history of ataxia-telangiectasia. Even parents of a child with this disorder may have a slight increased risk of cancer. They should have genetic counseling and more intensive screening for cancer.

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