John H. Stone discussed the IgG4 related disease. IgG4 related disease is a great mimicker. It has subacute evolution and responsiveness to treatment. IgG4 related kidney disease includes TIN, Membranous GM, Retroperitoneal fibrosis, and mass lesions at UPJ. Hypocomplementemia is the rule with renal disease. Multi-organ disease usually presents in most cases that need to be identified. More discoveries and better treatments for IgG4RD are expected soon.