**Core Concept:** Dubin-Johnson syndrome is a rare autosomal recessive disorder characterized by the accumulation of conjugated bilirubin in the liver cells (hepatocytes), leading to a yellowish discolouration of the liver and spleen. It is caused by mutations in the RTEL1 gene, which encodes for the helicase protein involved in DNA unwinding and telomere maintenance. The disorder results in impaired bile secretion and impaired bilirubin conjugation, causing hyperbilirubinemia.

**Why the Correct Answer is Right:** In Dubin-Johnson syndrome, the liver cells (hepatocytes) retain conjugated bilirubin due to the impaired bile secretion and conjugation pathways. This leads to hyperbilirubinemia and the characteristic yellow discolouration of the liver and spleen.

**Why Each Wrong Option is Incorrect:**

A. **Incorrect**: Bile salts are secreted into the bile ducts in normal circumstances, allowing the liver to be yellow when bruised. In Dubin-Johnson syndrome, the hepatocytes retain conjugated bilirubin, not bile salts.

B. **Incorrect**: Hepatocellular carcinoma is a malignant tumor arising from hepatocytes, not a characteristic feature of Dubin-Johnson syndrome.

C. **Incorrect**: The liver appears yellow due to retained conjugated bilirubin, not due to impaired liver function.

D. **Incorrect**: Jaundice is a result of impaired liver function, while Dubin-Johnson syndrome presents with retained conjugated bilirubin in the hepatocytes.

**Clinical Pearl:** Dubin-Johnson syndrome is clinically distinct from other liver disorders like Gilbert's syndrome and primary biliary cholangitis, with a clear-cut clinical presentation and absence of cholestasis. It is usually diagnosed in childhood or adolescence, and treatment is supportive and symptomatic, focusing on managing hyperbilirubinemia and its complications.

**Correct Answer:** Dubin-Johnson syndrome (DJS) is a rare autosomal recessive disorder characterized by the retention of conjugated bilirubin in liver cells (hepatocytes), leading to hyperbilirubinemia and yellow discolouration of the liver and spleen. It is distinct from other liver disorders like Gilbert's syndrome and primary biliary cholangitis, and is usually diagnosed in childhood or adolescence. Treatment is supportive and symptomatic, focusing on managing hyperbilirubinemia and its complications.

**Explanation:** In Dubin-Johnson syndrome, the liver cells (hepatocytes) retain conjugated bilirubin due to mutations in the RTEL1 gene, which encodes for the helicase protein. This protein is involved in DNA repair and telomere maintenance, but its dysfunction in Dubin-Johnson syndrome leads to impaired bile salt secretion, resulting in the retention of conjugated bilirubin in the liver cells.

**Clinical Pearls:**

1. **Clinical Pearls:** The unique yellow discolouration of the liver and spleen is a key clinical finding in Dubin-Johnson