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)

For this study, we are studying the relationship between variations in the genes of the immune system called HLA and how they relate to:

1. The risk of developing nephrotic syndrome
2. The response to treatment of nephrotic syndrome and
3. The risk of recurrence of nephrotic syndrome following kidney transplantation.

1. Clinical diagnosis of nephrotic syndrome
2. Biopsy proven diagnosis of FSGS or MCD and,
3. History of living or deceased donor kidney transplantation