Eikmans et al. [20] quantized the mRNA levels of TGF-β, Collagen I (COL1A1) and IV (COL4A1), and Fibronectin (FN1) by qRT-PCR in separated compartments (glomeruli and tubule-interstitium) of kidney biopsies carried out in 52 patients with various chronic kidney diseases, of which 10 were IgAN, and 16 were controls (cadaveric kidney donors). Here, FN1 is linked to chronic kidney disease.