INVS and Splenomegaly: Of the older Inv-KD mice (18 months old, six mice), we found apparent polycystic kidney development that showed a mildly enlarged and fibrotic kidney with apparent multiple cysts at high frequency (five mice) and splenomegaly (four mice) that were not observed in litter mate Inv::GFP-rescue mice (Fig. 2 a–i).