Biliary atresia is a blockage or absence of bile ducts that irreversibly prevents bile flow from the liver to the small intestine, causing accumulation of bile that damages the liver. The damage leads to scarring, loss of liver tissue and cirrhosis, which makes it difficult for the liver to remove toxins from the blood and deteriorates the liver. Biliary atresia is life threatening and a common reason for liver transplantation in children. The estimated worldwide incidence of biliary atresia is 18.5 per 100,000 births.
There are no medicines currently approved to treat biliary atresia. The typical treatment is a surgery known as the Kasai procedure, or hepatoporto-enterostomy, in which the obstructed bile ducts are removed and a section of the small intestine is connected to the liver directly. The chance of a successful Kasai procedure is best if done before two months of age. However, even with early intervention, scarring of the liver can continue, resulting in cirrhosis and eventually transplantation. Only about 25 percent of those initially undergoing the Kasai will survive into their twenties without need for liver transplantation.
The exact cause of biliary atresia is unknown, but it is thought to result from an event in the womb or around the time of birth. Possible triggers may include viral or bacterial infection, an immune system malfunction, a genetic mutation, a problem during liver or bile duct development or exposure to toxic substances.