Which of the following is a B2 hepatic disease?

• A. Gilbert Syndrome
• B. DJS
• C. Neonatal Hyperbilirubinemia
• D. Chronic Cirrhosis

Answer: (B)

B2 hepatic disease refers to disorders where the liver’s ability to excrete conjugated bilirubin into the bile is impaired, leading to an accumulation of conjugated bilirubin in the blood. Dubin-Johnson syndrome is a hereditary defect in the canalicular transport of conjugated bilirubin (often due to MRP2 transporter malfunction), so bilirubin that has been conjugated in the liver cannot be properly excreted into bile and instead builds up in the bloodstream. This pattern of predominantly conjugated hyperbilirubinemia with a generally benign course fits the B2 category because the problem lies in excretion rather than in the conjugation step itself.

Gilbert syndrome, by contrast, stems from reduced activity of the enzyme that conjugates bilirubin, causing unconjugated hyperbilirubinemia rather than an excretory defect. Neonatal hyperbilirubinemia in newborns is mainly due to immaturity of hepatic uptake, conjugation, and excretion processes, and chronic cirrhosis represents a long-standing structural liver disease with mixed patterns rather than a specific excretory defect of conjugated bilirubin. Therefore, the condition that aligns with the defined B2 hepatic disease is the one involving impaired canalicular excretion of conjugated bilirubin.