FNIP1 and cystic kidney disease: In this study, we found that disruption of Fnip1 alone results in renal cyst formation and was surprisingly sufficient to initiate many of the molecular and cellular changes implicated in the development of PKD in humans, including decreased expression of organic ion transporters; increased oxidative metabolism; increased cellular growth; increased expression of cell adhesion molecules; and increased immune cell infiltration in areas directly surrounding cysts.