Ataxia-telangiectasia (A-T) is an inherited condition that affects the coordination of movement (ataxia), weakens the immune system, and increases the risk of cancer.
A-T becomes evident during early childhood, with affected children experiencing wobbling, staggering, and poor balance. Delayed motor skills, slurred speech, and difficulty following objects with their eyes are also common. By the age of 7 or 8, muscle control declines, making writing difficult, and most individuals need a wheelchair by age 10. People with A-T often have weakened immune systems, making them susceptible to infections, especially in the lungs. Additionally, they face an elevated risk of developing cancers, particularly leukemia or lymphoma, at an early age. Due to their hypersensitivity to X-ray radiation, commonly used in cancer therapy, individuals with A-T typically need to avoid such treatments.
A-T is caused by pathogenic (disease-causing) variants in the ATM gene and exhibits autosomal recessive inheritance. This means that both parents must be carriers to have a 25% chance to have a child with the condition. The risk of being a carrier is based on a person’s ancestry or ethnic background. For example, individuals of Ashkenazi Jewish descent have a 1 in 820 chance to be a carrier.
Carriers are at increased risk of developing certain cancers including breast, pancreatic, and possibly others. If you are found to be a carrier, a genetic counselor can talk to you in more detail about this risk and what it means.
Other names for this condition are Louis-Bar syndrome and telangiectasia, cerebello-oculocutaneous.
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Revised August 2023
