Dubin–Johnson syndrome

Bilirubin

Dubin–Johnson syndrome is a rare, inherited disorder characterized by chronic jaundice and an increase in conjugated bilirubin in the blood. It is an autosomal recessive condition caused by mutations in the ABCC2 gene, which encodes the multidrug resistance protein 2 (MRP2). This protein is responsible for transporting conjugated bilirubin from the liver cells into the bile.

Pathophysiology

The primary defect in Dubin–Johnson syndrome is the impaired secretion of conjugated bilirubin into the bile. This results in the accumulation of conjugated bilirubin in the liver and its subsequent release into the bloodstream, leading to jaundice. The liver in individuals with Dubin–Johnson syndrome typically appears grossly black due to the deposition of a pigment similar to melanin.

Clinical Features

Patients with Dubin–Johnson syndrome usually present with mild jaundice that may fluctuate in intensity. The jaundice is often noticed during adolescence or early adulthood. Other symptoms may include fatigue and abdominal discomfort, but many individuals remain asymptomatic. The condition does not typically lead to liver damage or affect life expectancy.

Diagnosis

The diagnosis of Dubin–Johnson syndrome is based on clinical presentation, laboratory findings, and genetic testing. Key laboratory findings include elevated levels of conjugated bilirubin in the blood with normal liver enzyme levels. A liver biopsy may show the characteristic dark pigmentation of the liver cells. Genetic testing can confirm mutations in the ABCC2 gene.

Treatment

There is no specific treatment for Dubin–Johnson syndrome. Management focuses on monitoring liver function and addressing any symptoms that arise. Patients are advised to avoid factors that may exacerbate jaundice, such as certain medications and alcohol.

Prognosis

The prognosis for individuals with Dubin–Johnson syndrome is generally good. The condition is benign and does not lead to significant liver damage or affect overall health. Regular follow-up with a healthcare provider is recommended to monitor liver function.

Related Pages

• Jaundice
• Bilirubin
• Liver
• Autosomal recessive disorder
• ABCC2

References

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