Cure Glomerulonephropathy Network (CureGN) is a multi-year study of 2,400 children and adults with four rare glomerular (kidney) diseases at over 50 centers in the US, Canada, and Italy. The purpose of CureGN is to create a patient research network to learn about four major causes of glomerular disease : 1. Minimal Change Disease (MCD) 2. Focal Segmental Glomerulosclerosis (FSGS) 3. Membranous Nephropathy (MN) 4. IgA Nephropathy (IgAN)