Immune complexes containing Gd-IgA1 are important in the pathogenesis of IgAN and IgAVN.[6] Gd-IgA1 is specifically detected in IgAN and IgAVN and not in other renal diseases.[6] Gd-IgA1, anti-Gd-IgA1 antibodies, and soluble Fc alpha receptor form immune complexes and bind to the transferrin receptor of mesangial cells, leading to mesangial cell activation and proliferation. This evidence concerns the gene FCAR and kidney disorder.