DLG4 and Alzheimer disease: Postsynaptic density protein 95 (PSD95) is an important factor that contributes to synaptic formation, and it has been proposed to be a molecular scaffold for receptors and the cytoskeleton in synapses.21, 22, 23 Furthermore, it has been reported that PSD95 immunoreactivity was reduced in AD patients and Tg2576 mice.21, 24, 25