Ataxia-Telangiectasia (Louis-Bar Syndrome): A Rare Childhood Genetic Disorder

Do you know what Ataxia-telangiectasia (A-T) is?
Also called Louis-Bar syndrome, this is a very rare genetic disorder that affects children worldwide, occurring in about 1 in 50,000 to 100,000 births. It is a progressive condition that impacts movement, immunity, and increases the risk of certain cancers.

The word ataxia means uncontrolled or uncoordinated movement, particularly affecting walking and balance. Telangiectasia refers to abnormally enlarged blood vessels that appear just beneath the skin, resembling fine red or spider-like veins. Together, these features form the hallmark of this challenging disorder.

Causes of Ataxia-Telangiectasia

A-T is an inherited genetic disorder passed on in an autosomal recessive pattern. This means a child develops the condition only if they inherit a faulty copy of the ATM gene from both parents. Mutations in the ATM gene lead to abnormal cell death in areas of the brain responsible for coordination and movement, particularly the cerebellum.

Both boys and girls can be equally affected. Parents who carry a single copy of the gene typically do not show symptoms but may pass it on to their children.

Symptoms of Ataxia-Telangiectasia

Symptoms usually begin in early childhood and progress with time. Some common signs include:

• Jerky or unstable walking (ataxia)
• Delayed walking milestones
• Abnormal or jerky eye movements
• Reduced coordination that worsens with age
• Developmental slowdown, with mental progress often halting after age 10–12
• Enlarged, visible blood vessels in the eyes, ears, and joints (telangiectasia)
• Skin discoloration, especially on sun-exposed areas
• Premature graying of hair
• Recurrent respiratory tract infections
• Increased sensitivity to radiation exposure
• Seizures
• Café-au-lait (coffee-colored) spots on the skin

Diagnosis of Ataxia-Telangiectasia

A paediatric neurologist or neurophysician usually identifies the disorder through:

• Physical examination and medical history review
• Signs such as a small spleen, absent reflexes, facial abnormalities, delayed growth, or unusual skin texture

Further tests may include:

• Blood tests: Alpha-fetoprotein (AFP), carcinoembryonic antigen, immunoglobulin levels (IgE, IgA)
• Genetic testing: To confirm ATM gene mutations
• Immunological studies: B and T cell screening
• Imaging tests: X-rays for the thymus gland (though radiation exposure is minimized)
• Glucose tolerance tests: To check for diabetes risk

Complications of Ataxia-Telangiectasia

As the condition progresses, children with A-T may experience serious health challenges, such as:

• Spinal deformities like scoliosis or kyphosis
• Severe, recurring respiratory infections
• Diabetes
• Cancers, particularly lymphomas and leukemias
• Progressive neurological disability

Sadly, A-T often shortens life expectancy. However, the age of survival varies greatly among individuals. Careful management and protection from infections can improve quality of life.

Prevention and Genetic Counselling

There is no way to completely prevent A-T, but genetic counselling can help families with a history of the disorder. Couples planning for children may undergo genetic screening to assess the risk of passing on the ATM mutation.

Interestingly, carriers (parents) of the gene also have a slightly increased risk of developing cancer. Hence, both children and their parents should consider regular cancer screening.

Treatment Options

Currently, there is no cure for ataxia-telangiectasia. Treatment focuses on managing symptoms and complications, such as:

• Physical therapy: To improve coordination and mobility
• Antibiotics: For recurrent infections
• Immune system support: Immunoglobulin replacement therapy in some cases
• Medications: To control seizures or diabetes if they occur
• Lifestyle adjustments: Avoiding radiation exposure, including unnecessary X-rays or radiation therapy

Supportive care, early interventions, and regular medical monitoring can significantly improve the quality of life.

When to See a Doctor

If your child exhibits symptoms such as delayed walking, frequent infections, unusual eye movements, or visible changes in blood vessels, it is essential to consult a pediatric neurologist as soon as possible. Early diagnosis helps in better management of the disorder and related complications.

Final Thoughts

Ataxia-telangiectasia is a rare but serious condition that not only affects movement and development but also weakens the immune system and increases cancer risk. While there is no definitive cure, early medical care, genetic counselling, and preventive strategies can help families cope better.

Awareness, timely intervention, and supportive care are the keys to improving the quality of life for children living with this condition.