Cytogenetic toxicity of D2O in human lymphocyte cultures. Increased sensitivity in Fanconi's anemia.

Chromosomal aberrations were scored in lymphocyte cultures from healthy individuals, patients with Bloom syndrome, and patients with Fanconi's anemia, after 4-5 h exposure to culture medium containing 90% heavy water (D2O). D2O treatment resulted in occasional pulverization of metaphases, and increased frequencies of chromosomal breakage. Patients with Fanconi's anemia were particularly sensitive to the chromosome breaking effect of D2O.