To examine the effect of podocyte depletion, the human diphtheria toxin receptor (hDTR) was specifically expressed in podocytes, generating the hDTR Fischer rat model (see Table 1), which has histopathological features commonly seen in the human disease focal segmental glomerulosclerosis (FSGS; see Glossary, Box 1), including mesangial expansion, segmental and global sclerosis (Wharram et al., 2005). This evidence concerns the gene HBEGF and focal segmental glomerulosclerosis.