Different sensitivity of diploid and trisomic cells from patients with Down syndrome mosaic after treatment with the trifunctional alkylating agent trenimon.

Normal and trisomic cells of patients with Down syndrome mosaic offer the unique possibility to study the effect of an additional chromosome no. 21 against an identical genetic background. Here we show that a significant increase in the frequency of Trenimon induced sister chromatid exchanges (SCEs) and chromosome aberrations can be found in trisomic lymphocytes and fibroblasts as compared to disomic cells. The relative increase was clearly higher for chromosomal breaks than for SCEs.