An international expert group led by Bruijn of Leiden University in the Netherlands has recently released a DN pathological typing system to better guide the clinical management of DN, which has been lacking consensus on the pathological typing of diabetic nephropathy (DN). The expert group classified DN into four types based on the characteristics of glomerular lesions in renal biopsy tissue and with reference to the degree of interstitial and vascular lesions, ranging from mild to severe disease from type I to type IV, as follows: Type I: Glomerular basement membrane thickening: under light microscopy, the biopsy tissue has only isolated glomerular basement membrane thickening and mild nonspecific hyperplasia. There is no glomerular thylakoid hyperplasia, no nodular hyperplasia of the thylakoid stroma (Kimmelstiel & dash; Wilson lesion) or less than 50% sclerosis of the spherical glomerulus. Type II: Glomerular thylakoid hyperplasia: subdivided into mild (IIa) and severe (IIb). Kidney biopsy reveals mild to severe glomerular tract hyperplasia without nodular sclerosis (Kimmelstiel-Wilson lesion) or less than 50% spherical glomerulosclerosis. Type III: nodular sclerosis (Kimmelstiel-Wilson lesion): at least 1 glomerulus with enlarged thylakoid stromal nodules (Kimmelstiel-Wilson), but less than 50% spherical glomerulosclerosis. Type IV: advanced diabetic nephropathy glomerulosclerosis: more than 50% sclerosis of spherical glomeruli and other clinical or pathological evidence supporting this lesion as a result of diabetic nephropathy.