PDE6B and attention deficit-hyperactivity disorder: The meta-analyses resulted in methylome-wide significant (FDR<0.05) ADHD associations in CD8T cells (RPL31P11 and KCNJ5) for peripheral blood, and, in cord blood, in monocytes (PDE6B), CD8T cells (KCNA3 and HAND2), and NK cells (KIFC1).