In fact, the PSD95 can also bind the NMDARs by means of its PDZ1 domain, and if they are overstimulated, as in many neurodegenerative diseases, they allow the influx of high amounts of Ca2+ into neuronal cells, triggering the nNOS interaction with PSD95’s PDZ2 and its consequent overactivation. This evidence concerns the gene DLG4 and neurodegenerative disease.