NCIt definition : Rare hereditary disease characterized by extreme sensitivity to ionizing radiation
or radiomimetic drugs because of a defect in DNA repair. AT heterozygosity is estimated
to occur in more than 2% of the U.S. population; heterozygotes exhibit increased radiation
sensitivity and are at increased risk for several types of cancer. The normal version
of the gene that is defective in AT appears to activate the p53-dependent response
to DNA damage.;
Alternative definition : NCI-GLOSS: A rare, inherited, progressive, degenerative disease of childhood that
causes loss of muscle control, a weakened immune system, and an increased risk of
cancer.;