A recent study from The American Journal of Human Genetics reports that smoking while pregnant can result in changes in the DNA of newborns. Through DNA methylation, smoking is able to change the expression of genes involved in birth defects, such as asthma.
Smoking while pregnant is known to cause birth defects, such as low birth weight, asthma, cleft lip/palates, and decreased pulmonary function. Although there is a strong understanding of the risks involved, over 12% of women in the United States alone continue to smoke while being pregnant.
The mechanisms behind birth defects which result from maternal smoking remains poorly understood, and researchers are beginning to look at the role of epigenetics in this mother-child relationship. Epigenetics are changes in gene expression as a result of external or environmental factors. Epigenetic changes (such as DNA methylation – the addition of methyl groups to DNA) have been implicated in many diseases such as cancer and can even influence the changes seen between twins as they grow older.
In a recently published study by The American Journal of Human Genetics, researchers observed the effects of maternal smoking on children, and whether epigenetics played any role. The DNA of almost 10,000 newborns and adolescents was used and examined for any presence of DNA methylation.
Researchers found that almost 4000 sites in the DNA were methylated as a result of maternal smoking during pregnancy. Researchers noted that many genes which are linked to birth complications resulting from smoking (ie. asthma, cleft palates/lips) were methylated. Researchers were also able to identify 2017 genes that were not previously linked to smoking and methylation in either newborns or adults. When compared with newborns, older children also had significant levels of DNA methylation.
The results of this study aid us in understanding the underlying mechanisms of smoking’s effect on birth defects, and demonstrate that the effects of smoking while pregnant continues to have an impact on children as they get older.
Written By: Alexandra Lostun, BSc