What is Dubin-Johnson syndrome?

Dubin-Johnson syndrome is primarily characterized by a defect in the hepatic excretion of bilirubin, specifically leading to the accumulation of conjugated bilirubin in the liver due to inadequate secretion into the bile canaliculi. This condition is caused by a genetic mutation affecting the transport mechanisms in liver cells, resulting in increased levels of conjugated (direct) bilirubin in the blood.

Individuals with Dubin-Johnson syndrome typically present with a mild elevation of bilirubin levels, which may not cause significant clinical symptoms. The pigment in the liver that gives it a dark appearance is due to the accumulation of certain organic compounds, which also correlates with the failure to effectively transport bilirubin into the bile.

This understanding illustrates how the underlying mechanism of the condition leads to the clinical manifestation of hyperbilirubinemia, without confounding factors such as autoimmune processes or vitamin deficiencies that are characteristic of other conditions.