Heterozygous mutations in either PKD1 or PKD2, which encode polycystin-1 (PC1) and polycystin-2 (PC2), respectively, cause autosomal dominant polycystic kidney disease (ADPKD). Induced pluripotent stem (iPS) cell lines established from three patients with ADPKD had underlying PKD1 mutations, and decreased expression of PC2 at the cilium. These results highlight the use of iPS cells in PKD research and the potential interaction of PC1 and PC2 in disease pathogenesis.