Renal tubular cystic disease and hepatic fibrosis exhibit a specific genetic pattern and pathological findings. The renal collecting tubules are dilated and the liver shows fibrosis with proliferation and dilatation of the bile ducts. The findings fall into a spectrum with marked renal disease and mild liver involvement at one end and mild renal involvement with severe liver disease at the other. Between these extremes lies an intermediate form which is genetically and pathologically similar, but exhibits a wide range of clinical and radiological findings due to the variability of renal and liver involvement.