Wnt/β-catenin signaling is activated when Wnt proteins bind to FZD/LRP, which inhibits GSK-3β.22 One of the two main kinases that cause β-catenin phosphorylation is GSK-3β, whose activation causes β-catenin to become phosphorylated and degraded.23 It has been shown that brains of AD patients have higher GSK-3β activity,24 which may be due to the AD brain downregulation of LRP6 and upregulation of DKK1. This evidence concerns the gene DKK1 and Alzheimer disease.