This coincided with findings of a high glucose-stimulated increase in collagen and fibronectin production in mesangial cells and proximal tubular cells, which is mediated by TGFβ activation.133, 134, 135 Although the pathologic consequences of increased TGFBIp in the proximal tubules remains unclear, it may play an important role in the degree of renal interstitial fibrosis, which is closely correlated with a progressive decline in renal function in DM.132. The gene discussed is TGFB1; the disease is diabetes mellitus.