Two stages of podocyte foot process effacement (FPE) may clearly be distinguished. Within the first stage, foot processes undergo tremendous changes in shape, losing their regular interdigitating pattern and retracting into short irregularly shaped cell projections. Slit diaphragms are lost or displaced from their usual position at the base and replaced by occludens-type junctions between the deformed, broadened foot processes. These changes are necessarily associated with considerable movements of these processes in relation to the glomerular basemenet membrane (GBM). The second phase, the completed stage of FPE, includes retraction of the foot processes into the primary podocyte cell processes, leading to broad flattened disc-like projections that cover the GBM, finally merging with the cell bodies. At this point, the cell bodies have lost their usual position floating above the GBM within the filtrate in Bowman space. Instead they broadly adhere directly to the GBM. The subpodocyte space beneath the podocyte cell body has largely disappeared in this stage.