The molecular mechanisms underlying (hereditary) fibropolycystic diseases of the liver are still incompletely understood, although germline mutations have been identified which are associated with specific forms such as mutations of the genes Pkd1 and Pkd2 in autosomal dominant polycystic kidney disease (ADPKD) (30, 32, 33). The gene discussed is PKD1; the disease is autosomal dominant polycystic kidney disease.