Synonyms
Meulengracht disease Gilbert-Meulengracht disease Gilbert syndrome
Definition – What is Meulengracht’s disease?
Meulengracht’s disease (Gilbert-Meulengracht’s disease, Gilbert syndrome) is a harmless disease caused by a congenital metabolic disorder of the liver. The disease is inherited from parents to children. Due to a gene mutation, bilirubin, the breakdown product of the red blood cells, is metabolised more slowly and excreted with the bile. As a result, the plasma level of bilirubin rises and leads to various symptoms.
Causes
The cause of Meulengracht’s disease is a so-called functional hyperbilirubinemia. This means that the bilirubin level in the blood plasma has risen above normal levels due to a liver dysfunction. Normally, hemoglobin, the main component of red blood cells, is converted to bilirubin in the liver and excreted with the bile through the intestines.
An important step in this process is the combination of bilirubin with glucuronic acid (conjugation) so that the bilirubin becomes water-soluble and the bile can be released in the conjugated form. In Meulengracht’s disease, the conjugation of bilirubin is disturbed by an enzyme defect. The responsible enzyme, UDP-glucuronoyltransferase, only functions to about 30 percent. As a result, the whole process is much slower and excess unconjugated bilirubin accumulates in the liver and blood (hyperbilirubinemia).
Diagnosis
The doctor diagnoses Meulengracht’s disease through a blood test. An elevated concentration of indirect (unconjugated) bilirubin in the blood plasma at otherwise normal liver and blood values gives an indication of the disease. Furthermore, the mutation in the gene of UDP-glucuronyltransferase can be detected by means of polymerase chain reaction (PCR). The symptoms of Meulengracht’s disease can be misinterpreted by both the patient and the physician and interpreted as a severe chronic liver disease (e.g. hepatitis B or hepatitis C), so in case of doubt, a genetic test is appropriate for clear detection.
Inheritance
Meulengracht’s disease is an inherited disorder in which a genetic mutation results in reduced activity of the enzyme UDP-glucuronyltransferase. This is an autosomal recessive inheritance, which means that the mutation must be present on both chromosomes (of mother and father) for the disease to break out in the child. Children whose parents or one parent is affected by the disease have a significantly higher risk of developing Meulengracht’s disease.
