Gilbert's syndrome is a common, mild liver condition in which the liver doesn't properly process a substance called bilirubin. Bilirubin is produced by the breakdown of red blood cells.
Gilbert's (zheel-BAYRZ) syndrome typically is harmless and doesn't require treatment.
Gilbert's syndrome is caused by an inherited gene mutation. You're born with Gilbert's syndrome, though it often goes undiscovered for many years. Gilbert's syndrome is often discovered by accident, such as when you have a blood test that shows elevated bilirubin levels.
Gilbert's syndrome is also known as constitutional hepatic dysfunction and familial nonhemolytic jaundice.