Homozygous mutations in the ATM gene cause ataxia-telangiectasia, an autosomal recessive neurodegenerative disease characterized by gradual cerebellar cortical atrophy, telangiectasia of the eyes and facial skin, immune deficiency, premature aging, increased likelihood of developing multiple types of malignancies, and heightened sensitivity to radiation therapies [7]. The gene discussed is ATM; the disease is telangiectasis.