FCGR2A encodes Fc gamma receptor IIa, a low-affinity IgG receptor expressed on the plasma membrane that binds the Fc region of immunoglobulin G and initiates cellular immune responses 1. The receptor promotes phagocytosis of opsonized antigens and activates cellular FcγRIIA on platelets and monocytes to propagate immune responses 1. FCGR2A is expressed across diverse immune contexts, including intestinal immune cells where it functions in IgG sensing 2, and myeloid cells in pancreatic cancer where expression increases during disease progression 3. Disease relevance is substantial. The FCGR2A H131R polymorphism significantly associates with Kawasaki disease susceptibility in Asian populations 4, and FCGR2A variants affect binding affinity for IgG, modulating inflammation in ulcerative colitis through commensal-IgG immune complexes that engage gut macrophages to induce IL-1β production and type 17 immunity 5. FCGR2A is also implicated in Takayasu arteritis 6 and identified as a hub biomarker for post-transplant renal fibrosis with positive correlation to immune cell infiltration 7. Conversely, FCGR2A rs1801274 shows no significant association with pneumonia susceptibility 8. These findings establish FCGR2A as a critical mediator of antibody-dependent immune activation with important roles in inflammatory and autoimmune diseases, particularly those involving dysregulated IgG responses.