ALB and focal segmental glomerulosclerosis: In brief, the hypothesis that both primary FSGS in the native kidneys and also recurrent disease in the allograft are likely due to circulating factors or the absence of a normally present factor in the plasma is supported by several lines of evidence: first, it has been shown that pretransplant serum of patients with FSGS may increase the permeability of glomeruli to albumin in vitro.