title: Sister-chromatid exchanges in lymphocytes from infants with Down's syndrome.
abstract: Sister-chromatid exchange (SCE) frequencies were studied in blood lymphocytes from 12 patients (3 females and 9 males) with Down's syndrome (DS). The mean frequency of SCE per metaphase for the patients (both sexes) was 9.2 +/- 0.8 which was significantly higher (P less than 0.01) than the mean SCE value (5.1 +/- 0.2) scored for 16 healthy infants (8 females and 8 males). A significant increase in the mean frequency of SCE in 12 parents of infants with DS (8.7 +/- 0.9 SCE/cell) was noticeable when compared with 20 parents of normal infants (6.3 +/- 0.1 SCE/cell). Increases in cellular division with reduction in their replication were also observed in patients with DS. Treatment with mitomycin C (0.05 micrograms/ml), hycanthone (0.1 micrograms/ml) and gamma-radiation (0.1 Gy) revealed a significant (P less than 0.01) increase in frequencies of SCE in DS lymphocytes and in those of their parents as compared to controls. These data may reveal a familial hypersensitivity reaction to these agents. The results indicate a genomic instability and deranged DNA-repair mechanisms which are accentuated by exposure to mutagenic agents, the underlying causal factor for which might be genetic.
authors.affiliation: Department of Biochemistry, Faculty of Agriculture and Biology, Al-Mustansiriya Medical College, Baghdad, Iraq.
authors.forename: E K
authors.initials: EK
authors.lastname: Shubber
authors.forename: H A
authors.initials: HA
authors.lastname: Hamami
authors.forename: B M
authors.initials: BM
authors.lastname: Allak
authors.forename: A H
authors.initials: AH
authors.lastname: Khaleel
mesh_terms: D000328:Adult; D000367:Age Factors; D000477:Alkylating Agents / Q000494:pharmacology; D000704:Analysis of Variance; D002453:Cell Cycle / Q000187:drug effects; D004260:DNA Repair / Q000187:drug effects / Q000528:radiation effects; D004314:Down Syndrome / Q000235:genetics*; D005260:Female; D005720:Gamma Rays / Q000009:adverse effects; D006801:Humans; D006826:Hycanthone / Q000494:pharmacology; D066298:In Vitro Techniques; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D016685:Mitomycin; D008937:Mitomycins / Q000494:pharmacology; D012044:Regression Analysis; D012737:Sex Factors; D012854:Sister Chromatid Exchange; D013997:Time Factors
chemical_list: D000477:Alkylating Agents; D008937:Mitomycins; D006826:Hycanthone; D016685:Mitomycin