Morphometric study of glomerular basement membrane and proximal tubular basement membrane in adult thin basement membrane disease

Background. Thin basement membrane disease (TBMD) is a benign hereditary glomerulopathy with a diffuse attenuation of glomerular basement membrane (GBM). Whether the development of renal basement membranes other than GBM is normal in TBMD has not yet been resolved. Methods. We performed a morphometric study to measure the thickness of GBM and proximal tubular basement membrane (P-TBM) in 44 adult patients with TBMD and in 10 adult diseased controls confirmed to have minor glomerular abnormalities. Results. There was a significant difference between the patients with TBMD and the diseased controls in the thickness of the GBM; however, there was no significant difference between the two groups in the thickness of the P-TBM. In the patients with TBMD, the thickness of the GBM was unchanged with age, but the thickness of the P-TBM increased with age, as did that in the diseased controls. Conclusion. Our morphometric study clarified that the development of P-TBM was normal in the patients with TBMD.