TGFB1 and nephrotic syndrome: Furthermore, urinary TGF-β excretion is increased in patients with nephrotic syndrome [7], IgA nephropathy [8] and focal segmental glomerulosclerosis (FSGS) [9]; and urinary TGF-β levels correlate with ECM accumulation in FSGS [10, 11] and may be a predictive marker for disease progression [12, 13].