APP and Alzheimer disease: Chromosome 5 signal, rs72758175, is located near PLK2 (polo-like kinase 2) that binds and phosphorylates Thr-668 and Ser-675 residues of amyloid precursor protein, which instigate Aβ production in hippocampal neurons, suggesting that PLK2 may be an important target molecule for AD treatment [46].