MRP2 gene defect results in which of the hereditary disorders of bilirubin metabolism and Transpo is:
**Core Concept**
The MRP2 gene encodes for the multidrug resistance-associated protein 2, which is responsible for the transport of conjugated bilirubin from hepatocytes into the bile canaliculi. A defect in the MRP2 gene leads to impaired bilirubin excretion and results in a hereditary disorder of bilirubin metabolism.
**Why the Correct Answer is Right**
The MRP2 gene defect is associated with Dubin-Johnson syndrome, a rare genetic disorder characterized by chronic jaundice due to an inability to secrete conjugated bilirubin into the bile. The defective MRP2 protein impairs the transport of conjugated bilirubin into the bile canaliculi, leading to its accumulation in the blood and tissues. This results in a characteristic black liver discoloration and chronic jaundice.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the MRP2 gene defect is not associated with Gilchrist's disease, a rare condition characterized by an inability to transport unconjugated bilirubin into the liver.
* **Option B:** This option is incorrect because the MRP2 gene defect is not associated with Crigler-Najjar syndrome, a rare condition characterized by an inability to convert unconjugated bilirubin to its conjugated form.
* **Option C:** This option is incorrect because the MRP2 gene defect is not associated withRotor syndrome, a rare condition characterized by a chronic elevation of conjugated bilirubin due to a defect in the hepatic transport of conjugated bilirubin.
**Clinical Pearl / High-Yield Fact**
Dubin-Johnson syndrome is a rare genetic disorder that results in chronic jaundice due to impaired bilirubin excretion. The characteristic black liver discoloration in Dubin-Johnson syndrome is due to the accumulation of epinephrine metabolites.
**Correct Answer: D. Dubin-Johnson syndrome**