CTNND2 encodes δ-catenin, a neural-specific protein with critical roles in synaptic development and maintenance. The protein functions as a key regulator of synaptic maturation, moderating neuronal excitation and excitability during postnatal development while supporting synapse maintenance in adults 1. CTNND2 promotes neuronal integrity and slows synaptic maturation through its interaction with SRGAP2 proteins, contributing to the extended period of synaptic development characteristic of human neurons 1. The protein is involved in cell adhesion processes and focal adhesion signaling pathways, regulating cellular proliferation, migration, and invasion through FAK and MEK1/2/ERK1/2 pathways 2. CTNND2 haploinsufficiency contributes to cognitive dysfunction through defective neuronal migration, as demonstrated in both human genetic studies and zebrafish models 3. Clinically, CTNND2 deletions are associated with Cri-du-Chat syndrome, causing severe intellectual disability and developmental abnormalities 4. The gene shows significant involvement in various cancers, including glioblastoma where loss-of-function mutations promote aggressive mesenchymal transformation 5, and melanoma where overexpression enhances tumor cell properties 2. Additionally, CTNND2 variants are linked to stroke risk, particularly small-vessel occlusion stroke in males 6.