It should be noted that very few PKD associated pathways are known to be directly regulated by the PKD1 and/or 2 gene and none of them has been proved to directly regulate the amount and function of the PKD proteins in cystic renal epithelial cells and in other neighboring cells, including ADPKD heterozygous renal epithelial cells, fibroblasts, and immune cells. The gene discussed is PKD1; the disease is autosomal dominant polycystic kidney disease.