Gilbert's syndrome is a finding, not a disease. It is found in about 5 per cent of the population and is due to raised levels of a natural pigment called bilirubin in the blood.
Bilirubin is the natural waste product the body produces in the breakdown of haemoglobin – the oxygen-carrying compound present within red blood cells.
New red blood cells are continuously being manufactured in the bone marrow and old cells broken down; each red cell lasts about 120 days.
Bilirubin is eliminated in the bile fluids produced by the liver, but in Gilbert's syndrome the enzyme reactions involved in this process are slower than average.
Because bilirubin has a yellow colour, an excess in the blood causes the person to be jaundiced.
Gilbert's syndrome is determined by a particular liver enzyme, and the tendency for this to be slower in action can be passed on genetically.
For this reason, it can be found more commonly in family members of someone who has the condition. Males are affected more often than females.
Other causes of jaundice
These are several reasons why jaundice can occur, and these need to be distinguished from Gilbert's syndrome.
Inflammation of the liver cells (hepatitis) caused by a viral infection (hepatitis A, B or C) or through drug-induced damage (eg paracetamol poisoning) cause jaundice because the damaged liver cells are unable to process bilirubin into its simpler forms.
2. Blockage of the bile flow
Bile leaves the liver through a system of ducts, initially very small, which link up and eventually form the main bile duct. This duct is connected to the digestive system just beyond the outlet of the stomach.
Blockage of the bile duct can occur for several reasons, including gallstones.
3. Excessive breakdown of red blood cells
Red cell life may be shortened as a rare side effect of some drugs or in a condition called haemolytic anaemia.
Gilbert's syndrome only shows increased bilirubin in the blood. Other tests are normal, but this is not the case with the other causes of jaundice.
Therefore it is usually easy for a doctor to make a diagnosis of Gilbert's syndrome. Further tests, such as liver biopsy, are not normally needed.
Consequences of Gilbert's syndrome
There are no serious consequences of Gilbert's syndrome, nor is it a condition needing treatment.
People with the condition are usually discovered by chance when routine blood tests show a rise of the bilirubin level in the blood.
People with Gilbert's syndrome only look jaundiced when the bilirubin level is high enough to make the skin sufficiently yellow to be seen, so many people have a slightly raised level and neither they nor anyone else notices it.
Sometimes if a person with Gilbert's syndrome is unwell for another reason, for example with flu, the bilirubin level may increase further. That's often when a tinge of jaundice gets noticed and so the condition is diagnosed.
Some people with Gilbert's syndrome find they get episodes of abdominal pain, but why this should be so is unknown.
The main message is that Gilbert's syndrome is a harmless condition and can be ignored.
Other people also read:
Jaundice: how does a person get jaundice?
Hepatitis: what are the symptoms of hepatitis?
Blood tests: find out how a blood test carried out.