Effects on DNA methylation of arsenic exposure in utero

摘要

In a previous study, we evaluated cord blood DNA methylation among children from Bangladesh, and we found that prenatal arsenic exposure appears to decrease DNA methylation of specific, cancer-re- lated genes, especially in boys. In the present study, we followed-up the same children at 9 years of age (N = 113). DNA methylation of venous blood was evaluated using the HumMeth450K from Illumina. Maternal urine samples for prenatal arsenic exposure were collected in gestational weeks 5 to 14 and child urine samples for current arsenic exposure were collected at 9 years of age. We found gender differences in the epigenetic response to arsenic: Based on the number of statistically significant CpGs, the effect of current exposure seemed to be the strongest for boys, while for girls, the effect of prenatal exposure was the strongest. The majority of CpGs significantly associated with arsenic were hypermethylated, suggesting dynamic responses to arsenic in early life.