HSPG2 and fibrosis: The tubulointerstitial fibrosis present after 2-weeks treatment of COL4A3−/− mice was only slightly inhibited by MMF in comparison to the PLC COL4A3 −/− mice as would be expected for this relatively short period of MMF treatment (WT: all areas with score = <1+; PLC: 13% - score 0, 34% - score 1+, 33% - score 2+, 20% - score 3+; MMF: 11% - score 0, 45% - score 1+, 31% - score 2+, 13% - score 3+), and glomerulosclerosis appeared to be unchanged by MMF (Additional file 2: Figure S1).