APBA2 (amyloid beta precursor protein binding family A member 2) is a neuronal adaptor protein primarily involved in synaptic transmission and APP processing. The protein functions as an adaptor in synaptic vesicle exocytosis by binding to presynaptic components and interacting directly with neurexin-1α (NRXN1α) at the presynaptic membrane 1. APBA2 facilitates neuronal protein trafficking and is essential for proper synaptic function 2. Mechanistically, APBA2 contains PDZ domains that enable binding to neurexin and other synaptic proteins, regulating their membrane trafficking and stabilization 2. The gene possesses a neuronal-specific promoter whose activity is regulated by DNA methylation and transcription factors like Pax5 3. Disease relevance is substantial across multiple neuropsychiatric conditions. APBA2 is implicated in Alzheimer's disease pathogenesis, where altered expression levels in brain regions including hippocampus and entorhinal cortex correlate with disease progression 45. Rare nonsynonymous mutations and copy number variations in APBA2 significantly contribute to autism spectrum disorder susceptibility, with maternally inherited microduplications within 15q13.1 and compound heterozygous mutations identified in affected sibships 16. Additionally, APBA2 expression patterns serve as potential diagnostic biomarkers in neurological disorders 4.