Fibrocystin also localizes to the primary cilia, and experiments in PKHD1-silenced HEK-293 T cells suggest that the role of PKHD1 in cyst formation is linked to modulation of intracellular calcium levels, promoting excessive epidermal growth factor-induced cellular proliferation [14]. Similar to ADPKD, there are genes other than PKHD1 that have been linked to ARPKD (Table 1). This evidence concerns the gene PKHD1 and autosomal recessive polycystic kidney disease.