Role of maternal exposures and newborn genotypes on newborn chromosome aberration frequencies

Maternal exposures may induce chromosome damage and birth defects in the fe tus. Polymorphic variation in genes coding for enzymes involved in metaboli c activation and detoxification of environmental procarcinogens may account for some of the differences in chromosome aberration frequencies in newbor ns. In this study, 40 mothers completed questionnaires regarding exposures they received during their pregnancy. Umbilical cord blood samples were ana lyzed for chromosome aberrations. An average of 1020 metaphase cell equival ents (equal to 1020 G-banded cells) were examined from each newborn. In 26 of the newborns, genotyping analysis was performed for genes functioning in metabolic activation and detoxification (cytochrome P450 genes: CYP2D6 and CYP1A1, and phase II genes: NAT1, NAT2, GSTT1, GSTM1, GSTP1, and epoxide h ydrolase). A significant association between the CYP1A1 MspI polymorphism a nd chromosome aberration frequencies was observed in the newborns (p = 0.02 ), with heterozygotes showing higher aberration frequencies than the wild t ype homozygotes. Some large differences in chromosome aberration frequencie s for other genotypes were also noted, but these were not statistically sig nificant. Exposure to tobacco smoke in utero also appeared to increase tran slocation frequencies. The mean frequency of translocations per 100 cell eq uivalents from newborns of mothers who smoked during pregnancy was signific antly higher than that of newborns whose mothers did not smoke (0.21 vs. 0. 11, respectively, p = 0.045). (C) 2000 Elsevier Science B.V. All rights res erved.