DKK1 and attention deficit-hyperactivity disorder: This study aims to elucidate the relationships among Wnt signaling (LRP6, CTNBB1, DKK1, DKK3), stress-related gene expression (SIRT1, FOXO1), and circadian gene regulation (CLOCK, BMAL1, CRY1, PER1, PER2, PER3) in HDFs from individuals with ADHD.