Vol. 220, No. 5, May 2015
disease. Considering the important implications of this association, we would like to add some information that can help clarify the message in their article. Autosomal recessive polycystic kidney disease (ARPKD) is a rare, inherited form of renal disease that tends to be evident early in life, and can have important associated liver abnormalities, most notably congenital hepatic fibrosis. The underlying abnormality, a mutation in the polycystic kidney and hepatic disease 1 gene, leads to disruption in expression of fibrocystin/polyductin, a protein that plays a key role in the development of collecting and intrahepatic duct tubular architecture.2 Autosomal dominant polycystic kidney disease (ADPKD), a relatively more common disorder responsible for 5% to 10% of patients who enter end-stage renal disease, is caused by mutations in genes that encode mechanosensory ion channels (PKD1 or 2; disrupting polycystin 1 and 2, respectively). These patients commonly present later in life, with multiple large cysts in the kidneys and other organs, most notably liver and pancreas. Liver cysts are particularly prevalent in this patient population, and can sometimes trigger symptoms by compression or infection.3 Liver cysts tend to be isolated in ADPKD. In contrast, in ARPKD, the saccular ectasias can be seen to communicate directly with the intrahepatic biliary system, a fact that might allow imaging modalities to distinguish between the two forms.4 Soares and colleagues5 correctly indicate the presence of an association between ductal plate malformation during embryogenesis and ARPKD, however, they state this is due to a mutation in the PKD1 gene and quote a reference dealing with ADPKD. Although seemingly a minor mistake, based on dramatic differences in patterns of presentation, management, and inheritance for the two types of PKD, the information provided is confusing. Caroli disease has been reported in up to 30% of ARPKD patients.2,6 In contrast,
disease. Considering the important implications of this association, we would like to add some information that can help clarify the message in their article. Autosomal recessive polycystic kidney disease (ARPKD) is a rare, inherited form of renal disease that tends to be evident early in life, and can have important associated liver abnormalities, most notably congenital hepatic fibrosis. The underlying abnormality, a mutation in the polycystic kidney and hepatic disease 1 gene, leads to disruption in expression of fibrocystin/polyductin, a protein that plays a key role in the development of collecting and intrahepatic duct tubular architecture.2 Autosomal dominant polycystic kidney disease (ADPKD), a relatively more common disorder responsible for 5% to 10% of patients who enter end-stage renal disease, is caused by mutations in genes that encode mechanosensory ion channels (PKD1 or 2; disrupting polycystin 1 and 2, respectively). These patients commonly present later in life, with multiple large cysts in the kidneys and other organs, most notably liver and pancreas. Liver cysts are particularly prevalent in this patient population, and can sometimes trigger symptoms by compression or infection.3 Liver cysts tend to be isolated in ADPKD. In contrast, in ARPKD, the saccular ectasias can be seen to communicate directly with the intrahepatic biliary system, a fact that might allow imaging modalities to distinguish between the two forms.4 Soares and colleagues5 correctly indicate the presence of an association between ductal plate malformation during embryogenesis and ARPKD, however, they state this is due to a mutation in the PKD1 gene and quote a reference dealing with ADPKD. Although seemingly a minor mistake, based on dramatic differences in patterns of presentation, management, and inheritance for the two types of PKD, the information provided is confusing. Caroli disease has been reported in up to 30% of ARPKD patients.2,6 In contrast,
