Which enzyme is deficient in Gilbert syndrome?

Gilbert’s syndrome is an inherited condition often discovered by accident, such as when someone has a blood test. It occurs due to a defect in the processing of bilirubin by the liver. The syndrome may cause the skin and the whites of the eyes to have a yellow tinge due to the build-up of bilirubin.

Gilbert’s syndrome is typically harmless and treatment isn’t required.

Which enzyme is deficient in Gilbert syndrome?

Gilbert syndrome is due to a genetic variant in the UGT1A1 gene which results in decreased activity of the bilirubin uridine diphosphate glucuronosyltransferase enzyme. It is typically inherited in an autosomal recessive pattern and occasionally in an autosomal dominant pattern depending on the type of variant.

Crigler-Najjar syndrome is caused by an absence or profoundly decreased level of the enzyme UDP-glucuronosyltransferase due to a genetic defect in the UGT1A1 gene. Severe hyperbilirubinemia has the potential to cause irreversible brain damage.