In autosomal dominant polycystic kidney disease (ADPKD), Pkd1 mutations cause PC-1 deficiency, leading to impaired mechanically induced Ca2+ influx, elevated cAMP levels, and PKA activation, thereby promoting tubular cell proliferation and cyst fluid secretion (Mangoo-Karim et al., 1989a; Mangoo-Karim et al., 1989b). This evidence concerns the gene PKD1 and cyst.