Age, gender, and sensitivity to bleomycin-induced chromosome breakage in Down's syndrome and control populations.

The free radical theory of aging suggests that cells from individuals with premature aging syndromes, such as Down's syndrome, might be especially sensitive to radical-induced DNA damage. Although existing studies support this hypothesis, little work has been done on examining the impact of increasing age on radical sensitivity within the Down's syndrome population. Additionally, intercellular heterogeneity and gender differences in radical sensitivity have not been investigated. In this study, bleomycin-induced chromosome breakage was measured in lymphocytes from a population of adult men and women with Down's syndrome (age range 20-60 years) and a population of normal control men and women of the same age range. Change in breakage rates as a function of age and intercellular heterogeneity in breakage rates were examined in males and females of both groups. The findings are discussed in connection with longevity and cancer risk in the old male population.