FCGR2C encodes Fc gamma receptor IIc, a low-affinity receptor for complexed immunoglobulin G that mediates antibody-dependent cellular cytotoxicity and immune complex phagocytosis 1. The gene exhibits extensive copy number variation and single nucleotide polymorphisms that significantly impact immune function and disease susceptibility 12. FCGR2C polymorphisms, particularly rs114945036 (c.134-96C>T), demonstrate population-specific effects on HIV-1 susceptibility - providing protection in Thai populations during the RV144 vaccine trial but increasing transmission risk in South African populations 34. These polymorphisms associate with altered gene expression of Fc-gamma receptors in B cells and influence vaccine efficacy through Fc-mediated antibody functions 53. The receptor serves as a prognostic biomarker in sepsis, with FCGR2C expression correlating with patient survival and immune cell infiltration, particularly B cells, NK cells, and neutrophils 6. Additionally, FCGR2C is implicated in autoimmune conditions like psoriasis, where it is differentially regulated as part of the TYK2 pathway 7. The complex genetic architecture of FCGR2C, involving both structural variants and regulatory polymorphisms, makes it a critical determinant of individual immune responses and therapeutic outcomes.