Genetic and acquired defects of glomerular permselectivity may lead to proteinuria and protein-losing nephropathy (PLN). Morbidity and mortality from complications of PLN may be severe even before progression to azotemia and renal failure. Leakage of plasma proteins into the glomerular filtrate can damage tubular cells and the function of the entire nephron. Detection, localization, and treatment of proteinuria are important to decrease the clinical signs and complications of PLN and the likelihood of progression to renal failure. Thorough diagnostic work-ups help to identify subsets of glomerular disease and their response to specific treatment protocols.
