In autosomal dominant polycystic liver disease, in which cysts form only within the liver, most causative genes encode ER-associated proteins, such as PRKCSH and SEC63, that play roles in protein transport, folding and trafficking to PC (10–13), (cyst genetics covering hepatic fibropolycystic disease in autosomal dominant polycystic kidney or liver disease and autosomal recessive polycystic kidney disease collectively referred to as PCLDs), summarised in Figure 1a and reviewed in (14). The gene discussed is PRKCSH; the disease is cyst.