[Chromosomal abnormalities in lymphocytes from a patient with Werner's syndrome in intact culture and after treatment with halogenated analogs of thymidine].

Four balanced chromosomal translocation, deletion of chromosome 15, and a break in chromosome 11 were detected in 100 G-banded metaphases of cultured lymphocytes of a patient with Werner's syndrome. We observed aneuploidy that included both trisomies and monosomies for various chromosomes. Halogenated analogs of thymidine in low doses increased significantly the incidence of chromosome aberrations accompanied by fragments. 5-Iododeoxyuridine induced lesions in centromeric regions of B-group chromosomes in 44.4% of all the cases of breaks. A hypothesis is proposed about the existence of a special mechanism for genetic control in changes in the cell nucleus and mitotic chromosome transformation. This mechanism can be manifested after the application of halogenated analogs of thymidine. The mutation involved in Werner's syndrome is presumably related to this mode of genetic control.