PKHD1 and autosomal dominant polycystic kidney disease: To explore the molecular relationship between Bicc1 and the other known human ADPKD and ARPKD causal genes, Pkd1, Pkd2, and Pkhd1, we first examined the Bicc1 mRNA levels in Pkd1−/−, Pkd2−/−, or Pkhd1−/− cells using qPCR and compared them to the levels in their littermate-generated wildtype counterparts [23], [25].