It has been previously established that lead exposure can be harmful for a developing baby, since it can pass through the placenta and affect fetal bones and organs, including the brain. Previous studies suggest that exposure to heavy metals can adversely affect an individual’s global DNA methylation profile.

Researchers at Wayne State University recently revealed that pregnant mothers with elevated levels of lead in their blood not only compromise fetal cells, but could also adversely affect their grandchildren!

The Multi-generational Effects Of Lead Exposure

Leading the study was Douglas Ruden, Ph.D., Professor in the Department of Obstetrics & Gynecology and the Institute of Environmental Health Sciences, Director of Epigenomics, and program leader in the Center for Urban Responses to Environmental Stressors. According to the results of his team, exposure to lead can cause specific alterations in DNA methylation, which is detected in dried blood spots beyond a single generation.

Neonatal blood spots of mothers and their children were collected from the Michigan Neonatal Biobank, a novel resource of neonatal dried blood spots obtained from children born in Michigan during and after 1984.

Ruden stated that this study was the first to highlight the fact that epigenetic effects of heavy metal environmental toxins extends beyond one generation in humans. They tested the hypothesis that human fetal germ cell, on exposure to toxins, develop epigenetic changes that also exist in the blood of newborns grandchildren.

“The results demonstrate that exposure to lead during pregnancy affects the process of DNA methylation in fetal germ cells, leading to altered DNA methylation in the grandchildren’s neonatal dried blood spots”, explained Ruden. “This is the first suggestion that exposure to an environmental toxin in pregnant women could have an epigenetic effect on DNA methylation in grandchildren as well”.

Beyond The Pilot Study

Researchers stated that their novel, two-generational study design could also help in identifying specific genes that could serve as biomarkers for future transgenerational studies involving risk-assessment.

According to Ruden, this pilot study has provided indirect evidence linking lead exposure in pregnant women to altered position-specific DNA methylation in grandchildren. However, these altered profiles are seemingly normalized during postnatal development. Further research will help explain the exact mechanisms involved and the degree of modification in the methylation process.

The study entitled ‘Multigenerational epigenetic inheritance in humans: DNA methylation changes associated with maternal exposure to lead can be transmitted to the grandchildren’, was published online in Scientific Reports.