Dear Tahereh,

 The  glomerular basement membrane (GBM) is thickened with normal basement membrane material in two common kidney disease, membranous nephropathy and diabetic nephropathy (kidney disease caused by diabetes). 

The GBM. Like all basement membranes, the GBM is a sheet-like extracellular matrix composed of four major macromolecules: laminin, type IV collagen, nidogen, and heparan sulfate proteoglycan, the major one in the GBM being agrin. Studies over the past two and a half decades have shown that 1) the GBM contains specific basement membrane protein isoforms; 2) some of these isoforms are crucial for glomerular development, morphology, and function; and 3) mutations in four of the nine known genes that encode the GBM’s components cause human kidney disease.

For more details on the above mentioned macromolecules and their role in membrane thickening can be found in the review article entitled " The Glomerular Basement Membrane"  contained in the following link:

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3334451/

Hoping this will be helpful,

Rafik