A rare disorder, present at birth, in which the small bile passages within the liver are obliterated resulting in persistent JAUNDICE. If diagnosed early (before 100 days of age) it can usually be treated successfully by the Kasai Procedure – removing the scarred portion of the biliary tree and attaching a loop of bowel to the cut liver surface (portoenterostomy). Late diagnosis or a failed Kasai is dealt with by liver transplantation.