PKD1 and autosomal dominant polycystic kidney disease: Mutations in two genes were linked to ADPKD: PKD1 codes for polycystin 1 (PC1), a plasma membrane resident receptor, and PKD2 codes for polycystin 2 (PC2) or TRPP2, a member of the transient receptor potential protein family that resides in the ER and the plasma membrane.