Kidney disease.

The diagnostic highlights under electron microscopy in hereditary nephropathies and glomerulonephritides are reviewed: Alport's syndrome--lamellation, fragmentation and reticulation of glomerular basement membrane; benign essential (familial) hematuria--glomerular basement membrane thinning; nail patella syndrome--moth eaten holes and collagen like fibrils in glomeruli; nephronophthisis--thickening, thinning, reticulation and loss of tubular basement membrane; intramembranous and epimembranous glomerulonephritis--unequivocal diagnosis in early and late stages; extracapillary glomerulonephritis--exact classification of the basic type of glomerulonephritis; segmental focal sclerosing glomerulonephritis--unequivocal diagnosis of early stages and differentiation from other forms of glomerulonephritis or other nephropathies; Schönlein-Henoch's syndrome--scanty subepithelial deposits encases by a thin lamella of lamina densa; SLE--deciphering mixed forms of glomerulonephritis and demonstration of virus-like tubular structures in endothelium, so-called organized deposits, interstitial immunocomplex nephritis; mixed IgG/IgM cryoglobulinaemia--crystalloid structure of deposits; IgA nephritis--unequivocal demonstration of mesangial deposits; congenital nephrotic syndrome--irregularity of glomerular basement membrane and finally amyloidosis--unequivocal diagnosis. It is concluded that electron microscopy contributes information of clinical relevance in 30% of cases. Thus, electron microscopy should be used (in addition to light microscopy and immunofluorescence), whenever a renal biopsy specimen is to be critically evaluated.