Autosomal recessive (infantile) polycystic kidney disease

Autosomal recessive polycystic kidney disease, also called infantile polycystic kidney disease, is a chronic, progressive condition that causes cystic dilatation of the renal collecting ducts and congenital hepatic fibrosis. It is caused by mutations in the PKHD1 gene and has a wide spectrum of phenotypic variability. Approximately 30% of cases manifest prenatally or in the neonatal period, typically with a 50% mortality rate, but the remainder have milder and more variable disease. The characteristic prenatal sonographic finding is massive, symmetrically enlarged and echogenic kidneys that fill and distend the fetal abdomen. With advancing gestation, tiny cysts may be visible. These classic cases are associated with Potter sequence-lack of amniotic fluid resulting in pulmonary hypoplasia that is often lethal. More challenging are cases with milder phenotype because the degree of renal enlargement is less impressive and echogenicity may be apparent only after mid-gestation. The differential diagnosis for these findings includes several genetic syndromes as well as a normal variant, and amniocentesis should be offered. Molecular genetic testing may be helpful in affected families.