New DNA “clock” could help measure development in young children

Scientists have developed a molecular “clock” that could reshape how pediatricians measure and monitor childhood growth and potentially allow for an earlier diagnosis of life-altering developmental disorders. The research, published in Proceedings of the National Academy of Sciences, describes how the addition of chemical tags to DNA over time can potentially be used to screen for developmental differences and health problems in children.

The study was led by researchers at BC Children’s Hospital, the University of British Columbia, and the University of California, Los Angeles. It is the first study to describe a method specifically designed for children, called the Pediatric-Buccal-Epigenetic (PedBE) clock, which measures chemical changes to determine the biological age of a child’s DNA.

Small chemical changes to DNA, known as epigenetic changes, alter how genes are expressed in certain tissues and cells. Some of these changes happen as a person ages and others may be in response to a person’s environment or life experiences. In adults, these patterns of epigenetic changes are well established. They can be used to accurately predict a person’s age from a DNA sample or, if a person’s epigenetic age differs from their actual age, the clock can point to differences in health, including age-related diseases and early mortality.

The PedBE clock was developed using DNA methylation profiles from 1032 healthy children whose ages ranged from a few weeks old to 20 years. The researchers found 94 different sites in the genome that, when tested together, could accurately predict a child’s age to within about 4 months. The team also found that children who spent longer in the womb showed an accelerated rate of DNA change by 3 months, demonstrating that this tool could be used to indicate an infant’s developmental stage. The analysis can be done cheaply and efficiently on cells collected from a cheek swab.

In a small pilot study, the researchers also found that children with autism spectrum disorder (ASD) showed a higher PedBE “age” than those considered to be developing typically, suggesting that the clock could be used to screen for ASD.

The researchers made the tool freely available along with the publication of this study so other research teams are able to use and experiment with the tool right away.

The study, “The PedBE clock accurately estimates DNA methylation age in pediatric buccal cells,” is available online at www.pnas.org/content/early/2019/10/09/1820843116.