Aspartate aminotransferase (AST): An enzyme that is found in the liver and red blood cells (as well as the heart, muscle, kidneys, and brain). The amount of AST in the blood and the ratio between ALT and AST is an indicator for liver health.

Alanine aminotransferase (ALT): An enzyme found in blood plasma and the liver (as well as various other tissues). The amount of AST in the blood and the ratio between ALT and AST is an indicator for liver health.

Ascites: Fluid build-up in the abdomen caused by high blood pressure in the vessels of the liver.

Bile: A fluid produced by the liver that helps digest fats in the small intestine. Bile contains bilirubin, fats and salts.

Bilirubin: Unconjugated bilirubin is a yellow product of the breakdown of red blood cells. Once unconjugated bilirubin reaches the liver, it is conjugated and then excreted through the bile duct system into the intestine. Total bilirubin is the addition of both the unconjugated and conjugated bilirubin levels that is circulating in the blood (serum).

Biliary Atresia: A rare newborn live disease resulting from blockage of the large bile ducts. The blockage prevents bile from draining out of the liver and into the small intestine. Without treatment, bile cannot leave the liver, resulting in damage and scarring to the liver.

Cholangiogram: An imaging procedure used to diagnose biliary atresia. A dye is injected into the bile duct system. An X-ray is then taken to see where the dye has moved to, showing the flow of bile through the bile duct system and into the intestines.

Cirrhosis: The development of scar tissue and nodules in the liver as a result of advanced liver disease.

Conjugated bilirubin: Once taken up by the liver, unconjugated bilirubin becomes conjugated by enzymes in the liver cells. The conjugated bilirubin is then excreted through the bile duct system to the intestine.

Direct Bilirubin: A laboratory test that approximates the amount of conjugated bilirubin in the blood.

Endoscopy: Examining the inside of an organ or body cavity using an endoscope. For example, an endoscope can be used to examine the inside of the digestive system.

Esophageal Varices: Enlarged sub-mucosal veins in the lower part of the esophagus (the muscular tube that connects the throat and stomach) that can result in bleeding. They most often occur in people with liver diseases.

Fibrinogen: A protein that helps with blood clotting.

Gamma-glutamyltransferase (GGT): An enzyme found in bile duct cells (as well as other tissues). The amount of GGT in the blood is an indicator for liver health.

Hepatic artery: The artery that supplies oxygenated blood to the liver.

Heterotaxia: A group of disorders that all involve the reversed right/left orientation of abdominal or chest organs.

Kasai Procedure (also called hepatoportoenterostomy): A surgical procedure often performed on infants with biliary atresia. During this operation, the blocked bile duct is removed and a segment of bowel is attached to the liver to serve as a conduit for bile flow. The purpose of the procedure is to allow bile to drain from the liver into the small intestine.

Liver Transplant: The replacement of a diseased liver with a healthy liver from another person (a donor).

Native Liver: A patient’s own liver (ie. not a transplanted liver).

Polysplenia: A developmental disease where a person has multiple small spleens rather than one normal-sized spleen.

Portal hypertension: High blood pressure in the portal venous system which consists of the portal vein flowing to the liver, the splenic vein draining the blood from the spleen and the mesenteric veins draining blood from the intestines.

Portal vein: The vein that transports blood from the intestine and spleen to the liver.

Splenomegaly: An enlarged spleen, which can be caused by portal hypertension.

Total Bilirubin: A laboratory measurement of the combined quantity of conjugated and unconjugated bilirubin in the blood.

Unconjugated bilirubin: Bilirubin that is not conjugated. Either it has not been conjugated by the liver cells or it has been converted from conjugated back to unconjugated bilirubin after reaching the intestine.

Varices: Abnormally dilated vessels which can cause bleeding.