New Resource Correlates Brain, Buccal DNA Methylation Patterns

A map linking genome-wide DNA methylation patterns between human brain and buccal samples is reported in Clinical Epigenetics this week, representing a resource for the interpretation of epigenome-wide association studies (EWAS) that use buccal samples to study the effects of DNA methylation on brain phenotypes. DNA methylation is one of the most frequently studies epigenetic marks and EWAS have become increasingly popular to assess the relationship between DNA methylation patterns and brain-related phenotypes. Because the primary organ of interest — the brain — is not typically accessible, these studies tend to use tissues that are more readily available such as buccal swab samples, but it is not clear how effective peripheral DNA methylation patterns are in inferring biological processes in the brain. To investigate, a group led by University of Lübeck scientists performed a correlation analysis between DNA methylation data on 120 paired post-mortem buccal and prefrontal cortex samples. The researchers identify 24,980 significantly correlated CpGs between both tissues and find a significant enrichment of both buccal and dorsolateral prefrontal cortex methylation quantitative trait loci among the correlated CpG sites. The data are freely available online.