An epigenetic clock for kids

Epigenetic clocks use DNA methylation to measure biological age. Differences between biological age and actual chronological age can reflect health issues.

Such clocks are constructed by measuring DNA methylation at multiple sites and correlating that with the known age. The most popular method of estimating DNA methylation age has a median difference between biological and chronological ages of up to 3.5 years. That’s a relatively small difference for adults but a huge one for children.

Now Steve Horvath of the University of California, Los Angeles; Michael S. Kobor of the University of British Columbia; and coworkers have developed an estimator of DNA methylation age specific to children (Proc. Natl. Acad. Sci. U.S.A. 2019, DOI: 10.1073/pnas.1820843116).

The researchers used a collection of cheek cells from individuals 0–20 years old. Data from 94 DNA methylation sites in 1,032 samples were used to construct the model, and 689 samples were a test set. The resulting DNA methylation age model has a median difference of only 0.35 years for the test set.

With a children-specific epigenetic clock, researchers may be better able to understand the factors that lead to development of DNA methylation and how it correlates with children’s health.

The work “is pretty exciting for those of us working in this area,” says Radhika Dhingra, an expert in DNA methylation aging at the University of North Carolina at Chapel Hill. Building an epigenetic clock from noninvasively collected cells will help scientists study aging in children, hopefully with disease prevention in mind, she says.