PKHD1 and autosomal recessive polycystic kidney disease: Independently, a study investigating PKHD1 (mutated in autosomal recessive PKD (ARPKD), and encoding a protein, fibrocystin, which functionally interacts with PKD1), also found a lower than expected rate of CRC in mutation bearers (0.42% in 3603 controls versus 0.027% in 3767 patients with CRC; p = 0.0002) [11].