From the Guidelines
Gilbert syndrome is a benign genetic liver disorder characterized by elevated levels of unconjugated bilirubin in the blood, typically requiring no treatment and having no significant impact on liver function or overall health. This condition is caused by a genetic mutation affecting the UGT1A1 enzyme, which is responsible for processing bilirubin, resulting in the liver being less efficient at removing bilirubin from the bloodstream [ 1 ]. According to the guidelines on the management of abnormal liver blood tests, Gilbert's syndrome is an inherited disorder of metabolism that leads to impaired conjugation via reduced activity of the enzyme glucuronyltransferase [ 1 ].
Key Characteristics of Gilbert Syndrome
- Elevated levels of unconjugated bilirubin in the blood
- No other liver abnormalities
- Typically harmless and requires no treatment
- Caused by a genetic mutation affecting the UGT1A1 enzyme
- Results in occasional mild jaundice during times of stress, illness, fasting, or physical exertion
Diagnosis and Management
Gilbert syndrome is often discovered incidentally during routine blood tests showing elevated bilirubin levels [ 1 ]. The majority of measurable bilirubin should be conjugated, even in individuals with significant liver disease, and if the majority of the elevated bilirubin comprises the unconjugated fraction, the cause is virtually always Gilbert's syndrome [ 1 ]. No medications, dietary restrictions, or lifestyle modifications are necessary, though maintaining good hydration and regular eating patterns may help minimize episodes of jaundice. People with Gilbert syndrome can be reassured that they have a benign condition that does not lead to liver damage or other health complications [ 1 ].
From the Research
Definition and Characteristics of Gilbert Syndrome
- Gilbert syndrome is a common autosomal dominant hereditary condition characterized by intermittent unconjugated hyperbilirubinemia in the absence of hepatocellular disease or hemolysis 2.
- It is caused by reduced uridine diphosphate-glucuronyl transferase activity, resulting in indirect hyperbilirubinemia 2, 3.
- The most common genotype of Gilbert syndrome is the homozygous polymorphism A(TA)7TAA in the promoter of the gene for UDP-glucuronosyltransferase 1A1 (UGT1A1) 2.
Clinical Presentation and Diagnosis
- Hyperbilirubinemia in Gilbert syndrome is typically first noticed as intermittent mild jaundice in adolescence 2.
- Diagnosis is often one of exclusion, but molecular genetic tests can be performed when there is a diagnostic problem 2.
- Mildly elevated total bilirubin with normal serum activities of liver transaminases, biliary damage markers, and red blood cell counts may indicate the presence of Gilbert's syndrome 4.
Complications and Associations
- Gilbert syndrome may potentiate severe hyperbilirubinemia and/or cholelithiasis when combined with other prevailing conditions such as breast feeding, G-6-PD deficiency, thalassemia, spherocytosis, or cystic fibrosis 2.
- It may also reduce plasma oxidation and affect drug metabolism 2.
- Gilbert syndrome has been associated with a reduced prevalence of chronic diseases, particularly cardiovascular diseases and type 2 diabetes mellitus 4.