Patients with focal segmental glomerulosclerosis (FSGS) who progress rapidly to end stage renal disease (ESRD) are at highest risk for development of recurrence of proteinuria following kidney transplantation. This study will look at serum specimens pre and post transplant, as well as kidney transplant specimens pre and post reperfusion to identify where the defects has occured that results in recurrence of proteinuria in a given kidney transplant.