The Cause of ARPKD/CHF
Abnormalities in a single gene (PKHD1) appear to cause greater than 99% of all ARPKD/CHF cases. It takes one of these defective genes from each parent for the “recessive” disorder to be present. As a fetus begins to develop, the formation of the kidneys and the liver are affected (ARPKD/CHF). The kidney collecting tubules/ducts are initially dilated and later become cystic. It is thought that in the liver ductal plate development is incomplete, this results in ductal plate malformation, dilatation, and fibrosis (scarring) of the portal tracts which carry blood to the liver and bile away from the liver. There may also be abnormalities in the portal vein.
For a recessive trait or disease to occur, both parents must carry and pass on the defective gene. Even though parents are “carriers” of the ARPKD gene, they never have symptoms or signs of the disorder. There is a 25% chance of the disorder occurring with each pregnancy when the parents are “carriers” of the gene. Typically there is no prior family history of the disease.