The pathological spectrum associated with the ultrastructural finding of thin glomerular basement membrane: A tertiary medical city experience and review of the literature.

Background: Thin glomerular basement membrane (GBM) has been noted in several glomerular diseases including IgA nephropathy, focal segmental glomerulosclerosis (FSGS), Fabry's disease, and Alport's syndrome. We conducted this study to investigate the pathological ultrastructural spectrum of thin GBMs, to identify associated diseases, and to measure the GBM thickness in thin GBMs in our adult population.
Materials and Methods: All renal biopsies with thin GBM, diagnosed between 2010 and 2016, were retrieved and reviewed.
Results: Of 24 cases, 50.0% were diagnosed with FSGS, 12.5% with IgA nephropathy, 8.3% with tubulointerstitial nephritis, 4.2% with acute thrombotic microangiopathy, 4.2% with focal global sclerosis, 4.2% with lupus nephritis, and 16.7% with only thin GBM disease. Mean GBM thickness was 213.4 ± 24.7 nm. Mean interstitial fibrosis/tubular atrophy percentage (IF/TA) was 27.9 ± 22.2%. There was no significant correlation between GBM thickness and patients' age or IF/TA percentage.
Conclusion: The association of thin GBM with FSGS and IgA nephropathy is high. Morphometric analysis of the GBM thickness should be made routine, noting that ethnic variations in the GBM thickness are reported. Cases of thin GBM should be reported to facilitate proper diagnosis and institute the most appropriate treatment.