Dubin-Johnson Syndrome

Dubin-Johnson Syndrome is a rare inherited condition that affects the liver's ability to process bilirubin, a substance made when the body breaks down old red blood cells. This condition causes a buildup of conjugated bilirubin in the blood, leading to a mild form of jaundice, which is a yellowing of the skin and eyes. The liver itself is otherwise healthy, and people with this syndrome usually do not experience serious liver damage or symptoms beyond jaundice. The disorder involves a problem with the liver cells' ability to transport bilirubin into the bile, which is necessary for its removal from the body. It primarily affects the hepatobiliary system, which includes the liver and bile ducts. Most individuals with this syndrome live normal lives without significant health problems.

Dubin-Johnson Syndrome is an autosomal recessive disorder characterized by a defect in the canalicular multispecific organic anion transporter (cMOAT), encoded by the ABCC2 gene. This defect impairs the hepatic excretion of conjugated bilirubin into the bile, resulting in chronic conjugated hyperbilirubinemia without hepatocellular injury. The hallmark pathological feature is the accumulation of a dark, melanin-like pigment in hepatocytes, giving the liver a characteristic black appearance on gross examination. Clinically, patients present with intermittent or persistent mild jaundice but typically have normal liver function tests aside from elevated conjugated bilirubin. The syndrome is benign and does not progress to liver failure or cirrhosis. It is important to distinguish this condition from other causes of cholestasis and hyperbilirubinemia.