PKD2 and cyst: Constitutive Pkd2 KO mice develop cystic kidneys, edema, and hemorrhage and die in utero around midgestation.1298., 1299., 1300. Kidney cysts originate from dilatations along all nephron segments mimicking cyst formation in human ADPKD, with the notable exception that cyst formation in ADPKD is focal due to loss of heterozygosity in individual tubule cells, whereas PKD mouse models display much more widespread cyst formation due to Pkd2 inactivation in all tubular epithelial cells.