Gilbert's syndrome is a common, inherited disorder that affects the liver. People with this disorder have increased serum (blood) bilirubin (a yellow pigment, which gives bile its colour. Bile is excreted by the liver and is used by the gut to change the nature of fats which are eaten).
Small amounts of bilirubin are normally present in the blood (serum bilirubin). It is produced from the natural breakdown of haemoglobin (the red pigment in blood) in bone marrow, the spleen and other organs. Bilirubin is carried by the blood to the liver, where it undergoes a series of chemical changes and is then excreted into the bile. Here it is known as a bile pigment (providing colour to bile) and it undergoes further chemical changes in the intestines and then passes out of the body. When red blood cells break down excessively or there is interference in the bile excretion process, the amount of bilirubin increases and may result in jaundice (a yellow discoloration of the skin and/or eyes).
In people with Gilbert's syndrome, the bilirubin level fluctuates. At times it may be within the normal range; at other times, the level may be higher than normal (but not dangerously so).
About half the people affected have inherited the condition. It is understood to be due to decreased activity of an enzyme in the liver.
Who gets it and who is at risk?
Gilbert's syndrome affects about 5% of the adult population. It is more common in males and is usually diagnosed when people are in their teens or early adulthood.
Symptoms and signs
Usually there are no obvious symptoms but sufferers may experience mild jaundice, bouts of abdominal pain, loss of appetite, fatigue and weakness.
Often Gilbert's syndrome is diagnosed by chance when liver function tests are performed on blood for another reason. In people with Gilbert's syndrome serum bilirubin increases with certain illnesses such as flu.
To avoid misdiagnosis, your doctor must distinguish between this benign disorder and other more serious causes of liver dysfunction. The diagnosis can usually be made by clinical history, physical examination, blood tests and urinalysis.
The diagnosis of Gilbert's syndrome is established primarily by documenting the persistence of an increased amount of serum bilirubin when other liver function tests are repeatedly normal. An ultrasound scan of the liver or liver biopsy (tissue sample analysis) may occasionally be necessary to rule out other abnormalities.
No treatment is required, as people with the disorder are asymtompatic and are not at risk of any serious complications.
People with the disorder lead normal, healthy lives.
When to call the doctor
As those with the syndrome are not actually ill most people with Gilbert's syndrome only find out about their condition by chance at a routine medical examination.
Scientists believe this condition is an inherited disorder and it cannot be prevented.
Reviewed by Prof Helmuth Reuter, University of Stellenbosch and Tygerberg Academic Hospital