Steroid resistant nephritic syndrome ?
Podocin The glomerular capillary wall is a filtering membrane and consists of the following structures i) Endothelial cells ii) Glomerular basement membrane iii) Visceral epithelial cells (podocytes) iv) Mesangial cells The visceral epithelial cell known as podocyte is impoant for the maintenance of glomerular barrier function. They are structurally complex cells that possess interdigitating foot processes (pedicels). The adjacent foot processes are separated by 20-30 rim wide filtration slits. The filtration slit or slit diaphragm maintains glomerular barrier function. They present a size selective distal diffusion barrier to the filtration of proteins and it is the cell type that is largely responsible for the synthesis of GBM components. Proteins located in the slit diaphragm control glomerular permeability. Impoant proteins have been identified in this regard - Nephrin - Podocin (impoant in structural organization of slit diaphragm) - CD2 associated protein and - Actin cytoskeleton The impoance of these proteins in maintaining glomerular permeability is demonstrated by the observation that mutations in the gene encoding them give rise to nephrotic syndrome. The mutations in these genes commonly lead to focal segmental glomerulosilerosis Gene Chromosome Protein encoded Disease NPHS1 19q 13 Nephrin Congenitial nephritic syndrome of the finnish type NPHS2 lq 25-31 Podocin Steroid resistant nephritic syndrome 30% cases Mutations in the podocyte action-binding protein oc actinin 4 also produce FSGS
Nephrin
Alpha-actinin-4
Podocin
Transient Receptor Potential 6