For example, DNAm annotated to the genes SKI, ZNF544, ST3GAL4, and PEX2 in cord blood at birth were prospectively associated with childhood ADHD symptom trajectories (12), and CREB5, ZBTB38, PPIL2, TRERF1, and ERC2 with ADHD childhood symptoms (14). This evidence concerns the gene PPIL2 and attention deficit-hyperactivity disorder.