Ataxia Telangiectasia (A-T) is a rare, inherited childhood neurological disorder that causes degeneration in the
part of the brain that controls motor movements and speech.
The gene responsible for A-T, known as ATM (ataxia-telangiectasia mutated) makes a
protein that activates a number of other proteins that control cell cycle, DNA repair,and
cell death. Without it, cells are unable to activate the cellular checkpoints that
protect against the damage of ionizing radiation and other agents that can harm DNA.
The most unusual symptom of A-T is an acute sensitivity to ionizing radiation, such
as X-rays or gamma-rays. The first signs of the disease, which include delayed development
of motor skills, poor balance, and slurred speech, usually occur during the first
decade of life. Telangiectasias (tiny, red "spider" veins), which appear in the corners
of the eyes or on the surface of the ears and cheeks, are characteristic of the disease,but
are not always present and generally do not appear in the first years of life.
About 20% of those with A-T develop cancer, most
frequently acute lymphocytic leukemia or lymphoma. Many people with A-T have a weakened
immune system, making them susceptible to recurrent respiratory infections. Other
features of the disease may include:
• Mild diabetes mellitus;
• Premature graying of the hair;
• Difficulty swallowing; and
• Delayed physical development.
Children with A-T usually have normal or above normal intelligence. A-T affects boys
and girls equally.