Epigenetic changes modify how genes are switched on and off, without altering DNA’s genetic code sequence. These epigenetic variations are reversible and can either be inherited from one’s parents, or occur as a result of environmental changes.
Researchers have found that a type of epigenetic modification, called DNA methylation, on a gene controlling fat tissue inflammation is linked to a heightened risk of developing childhood obesity. In samples of saliva from children, the presence of methylation at 17 sites on the NRF1 gene was strongly associated with the mother’s BMI and waist circumference and the children’s likelihood of being obese 3 years later. This suggests two important findings: one, that the risk of obesity is passed on from mother to child and secondly, that NRF1 methylation could act as a predictive biomarker for obesity.
Researcher, Shari Barkin, from the Children's Hospital at Vanderbilt spoke on the rationale behind the study, which was published in BMC Medical Genetics, saying: "Understanding the factors that predispose children to obesity is important and will pave the way toward better prevention and early intervention."
As part of the Growing Right Onto Wellness (GROW) trial, Barkin and colleagues collected saliva samples from over 600 parent-child pairs, where children were deemed at risk of developing obesity. The hope was that genetic factors in an easy to collect biological specimen would reveal potential trends and highlight at-risk children.
The study’s findings show that this was indeed possible. Children with NRF1 methylation had a three-fold odd of being obese when weighed three years later. Pediatric obesity is associated with the development of chronic conditions later in life, such as diabetes, heart disease, and cancer.
While lifestyle interventions can help, the ability to perform a simple, non-invasive test to determine the most at-risk individuals for targeted, early interventions will significantly improve their overall quality of life.
"Even though many of the children in our intervention group compared to our control group improved their nutrition, maintained physical activity consistent with guidelines and got sufficient sleep, 30% of them still emerged into obesity," said Barkin.
"This sheds new light on how we think about the interaction of behavior and genetics and how that might contribute to health disparities."