DLG3 (discs large MAGUK scaffold protein 3), also known as SAP102, is an X-linked scaffolding protein essential for synaptic organization and plasticity in the central nervous system 1. It functions as a site-specific organizational center clustering key synaptic components necessary for learning and memory by organizing excitatory synapses and their associated signaling molecules 2. DLG3 mediates its effects through interactions with NMDA receptors and regulates postsynaptic membrane receptor levels and localization 1. Hemizygous loss-of-function variants in DLG3 cause X-linked intellectual developmental disorder 90 (XLID90), a syndromic neurodevelopmental disorder frequently associated with morphological features and intellectual disability 3. DLG3 mutations have also been implicated in autism spectrum disorder and schizophrenia 41. Additionally, abnormal DLG3 expression links to psychiatric and neurodegenerative conditions including bipolar disorder, major depression, and Alzheimer's disease 1. Beyond neurology, DLG3 influences cancer biology. High DLG3 expression correlates with decreased survival in breast cancer and is associated with tumor progression 5. In glioma, COP1-mediated ubiquitination of DLG3 facilitates cell proliferation, invasion, and migration 6. DLG3 also regulates signaling pathways including PI3K/AKT and Hippo pathways relevant to tumorigenesis 1.