The cause of proteinuria in idiopathic nephrotic syndromes in children is increased permeability of the glomerular filtration barrier following the action of immune and non-immune . Podocytes , thanks to specific proteins of the cytoskeleton ( cytokeratin , vimentin , actin ) and particles stabilizing their intracellular organization (complex podokaliksyna - ezryna - On exchanger regulatory factor -H - actin , synaptopodin ) and proteins films fissured ( podocyn , nephrin ) are responsible for the proper filtration process in the glomerulus .