SOX9 and Alzheimer disease: In terms of WNT signaling, neurotrophic factor (NT)-α1 (also known as carboxypeptidase E, CPE) was suggested as a key Wnt-β-catenin dependent anti-proliferation factor and ERK-Sox9 activated inducer of embryonic neural stem cell differentiation to astrocytes in neurodevelopment [98] on the one hand, and as important factor for cognition and Alzheimer’s disease, on the other hand [99], indicating converging pathways with ADNP.