n. an epithelial cell in the *glomerulus that spreads over the capillary basement membrane and has branching tentacle-like processes that interdigitate with adjacent cells. The podocytes leave gaps or thin filtration slits. The slits are covered by slit diaphragms, which are composed of a number of cell-surface proteins including *nephrin, podocalyxin, and P-cadherin, which ensure that large molecules, such as albumin and gammaglobulin, are not filtered. Podocytes are damaged in *minimal change nephropathy and a major target of injury in *HIVAN.
a common cause of the *nephrotic syndrome in adults. The diagnosis is established by renal biopsy, which shows diffuse global subepithelial deposits within the glomerulus. Most cases of membranous nephropathy are idiopathic, but there are associations with infection (e.g. hepatitis B), malignancy (especially lung cancer), autoimmune disease (e.g. SLE, Hashimoto’s disease), and drugs (e.g. gold and penicillamine). Recent studies suggest that idiopathic membranous nephropathy is an autoimmune disease with antibodies directed against an antigen (PLA2R, a phospholipase A2 receptor) on the *podocyte cell membrane. Without treatment, outcome is very variable: some patients will make a full recovery, while others will progress to end-stage kidney failure. Immunosuppressant treatment is often tried when there is evidence of declining renal function.... membranous nephropathy
the commonest cause of *nephrotic syndrome in children and an important cause of this syndrome in adults. The condition is so named because of the apparent lack of abnormalities seen on light microscopy of biopsy samples. Changes can, however, be seen on electron microscopy, with effacement of the *podocyte foot processes along the glomerular basement membrane. It is postulated that minimal change disease is a T-cell disease and that *cytokine damage to the podocytes leads to loss of the selective filtering characteristics of the glomerulus. The condition usually responds to corticosteroids and has a good prognosis, but there is clinical overlap with primary *focal segmental glomerulosclerosis, which may have similar histological appearances in its early stages, tends not to respond to steroids, and is associated with a poor renal prognosis.... minimal change nephropathy
n. a transmembrane protein localized to the slit diaphragm of the *podocyte and necessary for the proper functioning of the renal filtration barrier. The latter consists of fenestrated endothelial cells, the basement membrane, and the epithelial podocyte. A defect in the gene coding for nephrin (NPHS1) on chromosome 19 results in congenital nephrotic syndrome of Finnish type (which is not exclusive to the Finnish population).... nephrin
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