5-Fluoro-2'-deoxyuridine induction of the fragile site on Xq28 associated with X linked mental retardation.

Abstract
5-Fluoro-2''-deoxyuridine (FUdR) is highly effective in inducing the heritable fragile site on Xq28 associated with mental retardation. Lymphocytes from 2 affected males manifested the fragile site in 30-40% of the mitoses when grown in the presence of FUdR. Depletion of the dTMP pool via thymidylate synthetase inhibition may be responsible for the expression of the heritable fragile site on Xq28.