NCAM2 is a neural cell adhesion molecule primarily expressed in the brain that functions as a key regulator of neuronal morphogenesis and cytoskeletal organization 1. Unlike its paralog NCAM1, NCAM2 contains five immunoglobulin modules and two fibronectin type III domains but lacks polysialic acid glycosylation, suggesting distinct functional mechanisms 1. NCAM2 regulates dendritic and axonal differentiation through interactions with cytoskeletal proteins MAP2 and 14-3-3, promoting neurite outgrowth and neuronal polarization 2. During development, NCAM2 controls dendritic architecture formation, axonal compartmentalization, and cortical migration 23. In the adult brain, NCAM2 is highly expressed in dendritic spines where it regulates synaptic plasticity, learning, and memory formation 3. NCAM2 also regulates adult neurogenesis by controlling radial glial progenitor differentiation in the hippocampus 4. Clinically, NCAM2 is implicated in Alzheimer's disease pathogenesis: amyloid-β binding induces NCAM2 removal from synapses and cleavage of its extracellular domain, contributing to synapse loss 5. Additionally, NCAM2 promotes APP targeting to BACE1-containing recycling endosomes, increasing amyloidogenic processing and amyloid-β production 6. These findings suggest NCAM2 involvement in neurodevelopmental disorders and neurodegeneration.