Hi, Tiger is right, it's a rather common syndrome that is usually discovered by accident. Here is the full definition from the Mayo Clinic.
"Gilbert's (zheel-BAR) syndrome is a common, harmless liver condition in which the liver doesn't properly process bilirubin. Bilirubin is produced by the breakdown of red blood cells.
If you have Gilbert's syndrome — also known as constitutional hepatic dysfunction and familial nonhemolytic jaundice — you're born with it as a result of an inherited gene mutation. You might not know you have the condition until it's discovered by accident, such as when a blood test shows elevated bilirubin levels. Gilbert's syndrome requires no treatment."
