Disease of the month: Gilbert’s syndrome

A quite common and relatively benign condition often seen on insurance applications, Paul Gyseman discusses the insurability factors and the pathophysiology of this illness

Gilbert’s syndrome (unconjugated hyperbilirubinaemia) is a common hereditary condition that affects about one person in 20 in the UK.

Broadly speaking, however, only one person in every three who has the illness is actually aware of it.

Named by French gastroenterologist Nicolas Augustin Gilbert in 1901, Gilbert’s is a genetic condition of the autosomal recessive variety and it is therefore inherited from both parents.

It is not a true ‘disease’, despite it being sometimes called Gilbert’s disease. It is often diagnosed to people in their late teens or early 20s and affects men more so than women.

Gilbert’s syndrome is caused by the inability of the liver to effectively process bilirubin, which is a breakdown product of haemoglobin, the chemical found in red blood cells that carries oxygen to the body’s tissues and organs.

These blood cells ‘break down’ each day and bilirubin forms a by-product of this process. The liver then processes the bilirubin, which is then passed out into the gut.

There is a certain enzyme, uridine diphosphate glucuronosyltransferase (UGT), found within liver cells that assists with the processing of bilirubin and it is this enzyme that is deficient in sufferers of Gilbert’s syndrome.

The low levels of UGT, therefore, results in increased amounts or a ‘backlog’ of bilirubin within the blood stream, which can be measured by laboratory technicians.

A blood count will usually show normal values of liver enzymes such as total serum protein, aspartate aminotransferase (AST), alanine aminotransferase (ALT) and gamma glutamyl transpeptidase (GGT), but the serum bilirubin will be elevated with no obvious cause.

The normal value for total serum bilirubin is 0.3-1.0 mg/dl. In most cases of Gilbert’s syndrome, there are no symptoms ­whatsoever and the sufferer is made aware of the condition only through a chance finding  usually when being investigated for something else or at a routine health screening.

IMPACT OF JAUNDICE

However, some sufferers get jaundiced from time to time when the level of bilirubin becomes excessive.

Jaundice means that the whites of the eyes and the skin become yellow, reflecting the excessive levels of bilirubin within the system (for example, more than 3.0 mg/dl).

Because jaundice can be caused by other, more serious underlying pathologies of the liver and bile ducts, it is important for both the applicant and therefore the underwriter to be sure that the diagnosis is certain and that there is not another cause to the jaundice, such as hepatitis.

While jaundice may seem quite alarming initially, it often occurs only when the sufferer is generally unwell with an infection, has had significant stressful episodes in their life or has undergone surgery.

In rare circumstances, other symptoms of Gilbert’s syndrome include tiredness, nausea, weakness, abdominal pain and irritable bowel.

Yet these ­symptoms are not ­necessarily related to the elevated bilirubin levels. More often than not, they are secondary findings as a result of the stress and anxiety that some sufferers experience simply by knowing that they have the condition.