APBB2 (amyloid beta precursor protein binding family B member 2) is an adaptor protein that activates transcription of APP and modulates amyloid-beta processing 1. The protein maintains lens transparency and participates in hippocampal neurite branching and neuromuscular junction formation, contributing to spatial memory function [UniProt]. APBB2 functions through protein binding and intracellular signal transduction mechanisms in the cytoplasm, nucleus, and at synapses. Disease relevance of APBB2 spans multiple conditions. Genetic variants in APBB2 associate with late-onset Alzheimer's disease (LOAD), with certain SNPs showing significant association (rs13133980: OR=1.36-2.43 depending on age group) 2. APBB2 overexpression promotes beta-amyloid formation, implicating it in amyloid pathology 3. The gene also associates with severe cognitive impairment in centenarians 3 and sporadic Alzheimer's disease, particularly in younger-onset cases 4. Beyond neurodegeneration, APBB2 variants associate with opioid use disorder susceptibility 5 and amphetamine use in methadone-maintained patients 6. APBB2 is upregulated in gastric adenocarcinoma where silencing inhibits proliferation and metastasis 7, and serves as a potential biomarker for HIV-1 latency 8. Recent evidence links APBB2 variants to Takayasu arteritis angiographic patterns 9.