In adults, the most common reason for liver transplantation is cirrhosis. Cirrhosis can be caused by viruses such as Hepatitis B and C, alcohol, autoimmune liver diseases, build-up of fat in the liver, or hereditary liver diseases.
In children, the most common reason for liver transplantation is biliary atresia. Bile ducts, which are tubes that carry bile out of the liver, are missing or damaged in this disease, and obstructed bile causes cirrhosis.
Other reasons for transplantation include liver cancer, benign liver tumours and hereditary diseases. Sometimes, the cause of liver disease is unknown, and this is called cryptogenic.