Experts don’t know what causes biliary atresia. Research suggests that infants develop biliary atresia in the womb or shortly after birth. Experts are trying to find out if one or more of the following factors could play a role in causing biliary atresia:
__infections with certain viruses
__coming into contact with harmful chemicals
__problems with the immune system
__a problem during liver and bile duct development in the womb
__certain genes or changes in genes-called mutations-that may increase the chances of developing biliary atresia

Biliary atresia is not an inherited disease, meaning it does not pass from parent to child.