Considering overlap with genetic (rather than epigenetic) studies, four of the CpGs we found to be associated with attention problems in our study were located in genes that have been linked to ADHD in prior GWAS (FGFR1, NFIA, PIK3R2, PITPNM3) [45, 46]. This evidence concerns the gene PIK3R2 and attention deficit-hyperactivity disorder.