SYP and Alzheimer disease: The neurons derived from our AD-iPSCs demonstrated aberrant accumulation of intracellular and secreted Aβ42 and Aβ40, reduction of serine 9 phosphorylation in glycogen synthase kinase 3β (GSK3β) hyperphosphorylation of threonine 181 and serine 396 in tau protein, impaired neurite outgrowth, downregulation of synaptophysin, and increased caspase 1 activity.