agingA new study has identified several genomic loci that influence age-related methylation in the human brain which overlap with loci linked to a range of other conditions. The research was published in Nature Communications last week.

To better understand the impact DNA methylation has on the brain, the researchers used a genome-wide association study approach to find genetic variants that influenced the epigenetic changes. They tested 1,796 post-mortem brain samples taken from the prefrontal cortex, cerebellum, frontal cortex, pons, and the temporal cortex of 1,163 people with European ancestry. The participants’ age of death ranged from 1 to 108 years old.

By observing more than 350 cytosine-methylation marks implicated in aging, the team found that a number of the loci were also implicated in age-related macular degeneration, and a range of cognitive, psychiatric, metabolic, and inflammatory conditions. In total, they were able to identify 21 different traits/conditions that demonstrated genomic overlap with the regions being investigated. They also noted that the majority of these loci led to chromosome 1 and chromosome 17.

The study also investigated the proportion of neurons to other brain cells. Previous research has indicated that this proportion increases with age as the number of glial support cells decreases, an effect supported by the observations in this study. In particular, the team noted that the loci involved in this process were largely tied to chromosomes 10 and 12.

“The biological relevance of these finding is supported by our findings that both biomarkers of brain aging relate to a host of age-related phenotypes according to GWAS results,” the authors wrote. “Overall, this study elucidates the genetic architecture of epigenetic and neuronal ageing rates in human brain regions.”

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