CDH15 (cadherin 15) is a calcium-dependent cell adhesion molecule that mediates homophilic cell-cell interactions and plays critical roles in neural development and synaptic function 1. As a member of the cadherin superfamily, CDH15 regulates neural tube regionalization, neuronal migration, spine morphology, and synapse formation 1. The protein functions through calcium-dependent adhesive mechanisms and interacts with catenin complexes at adherens junctions to facilitate cell-cell junction assembly and organization. CDH15 variants have been associated with intellectual disability and neurodevelopmental disorders. In vivo studies demonstrate that CDH15 mutations adversely affect its ability to mediate cell-cell adhesion in neurons 2. Genome-wide association studies link CDH15 to cognitive impairment and autism spectrum disorder 1. Recent proteomic studies identify CDH15 as a potential biomarker for seizure activity, with significantly altered plasma levels in patients with recent seizures compared to seizure-free individuals 3. Additionally, CDH15 has emerged as a candidate circulating protein biomarker and potential therapeutic target for interstitial lung disease and sarcoidosis 4, and shows associations with neuroinflammatory processes in multiple sclerosis 5. Its role in cell adhesion and neural circuit integrity positions CDH15 as therapeutically relevant for neurodevelopmental and neurological conditions.