[Effect of chlormethin chlorhydrate on the chromosomes in Fanconi's anemia: application to diagnosis and detection of heterozygotes].

Nitrogen mustard added at final concentration of 0.008 5 microgram/ml after 1 day to culture of PHA-stimulated lymphocytes increased drastically the level of chromosome breakage in Fanconi's anemia (FA) patients. A clear distinction between FA patients and FA parents or controls was therefore possible. Nitrogen mustard at the same concentration added to the culture since their initiation increased the SCE levels in FA heterozygotes significantly compared with controls, allowing the diagnosis of the heterozygous state.