Gilbert’s Syndrome

Gilbert’s syndrome (GS) is a condition in which you have higher than normal amounts of bilirubin in your blood.

The medical name for this is ‘unconjugated hyperbilirubinemia’. It is also sometimes called familial nonhaemolytic bilirubinaemia or constitutional hepatic dysfunction.
These long names may not sound promising but GS is in fact a harmless condition. It is not a disease and it is possible that you may not even know you have it.

Facts about Gilbert’s Syndrome

GS was first identified by the French doctors Nicolas Augustin Gilbert (after whom it is named) and Pierre Lereboullet in 1900. They described a syndrome of benign, periodic but chronic jaundice occurring without any other symptoms of liver disease.  
Today, GS is relatively common. It is thought to affect about one person in 20 or about 4% of the population. Some estimates are higher. It affects both males and females. GS is thought to be hereditary, meaning that it is caused by a gene that runs in your family.
Genes contain the instructions for making up your body. GS is caused by a variant gene that has a ‘mutation.  
A mutation is a permanent change in the code of the DNA making up a gene or chromosome. This can alter the way a physical characteristic is expressed or cause some function in the body to occur differently. Sometimes the word ‘variant’ is used instead of mutation as many changes do not cause any disorder.  
In GS the mutation causes ‘reduced gene expression’, meaning that it limits production of the specific UGT enzyme (called UGT1A1) responsible for conjugating bilirubin.