LIN7B (lin-7 cell polarity scaffold B) is a membrane-associated scaffold protein located on chromosome 19.41 that establishes and maintains asymmetric distribution of ion channels and receptors at polarized cell plasma membranes 1. LIN7B functions as part of a tripartite complex with CASK and APBA1 to regulate protein delivery and recycling to correct membrane domains, including trafficking of NMDA receptor subunit NR2B to neuronal postsynaptic densities and localization of Kir2 channels and GABA transporters to epithelial basolateral membranes 1. During brain development, LIN7B is essential for excitatory neuron migration and interhemispheric axon growth; acute knockdown causes delayed cortical neuronal migration and impaired axon extension 2. Mutations and duplications in LIN7B have been identified in autism spectrum disorder patients, suggesting functional deficiencies contribute to abnormal cortical architecture 2. LIN7B expression is significantly decreased in Huntington disease layer 5 motor cortex neurons, potentially contributing to impaired corticostriatal connectivity and motor dysfunction 3. In spinal cord injury, LIN7B expression is reduced alongside other synaptic hub genes, indicating its involvement in injury response mechanisms 4. Recent proteomic studies identified LIN7B as a cerebrospinal fluid biomarker consistently associated with neuropsychiatric symptom progression in mild cognitive impairment and Alzheimer's disease 5.