MRP 2 and conjugated hyperbilirubinemia associated with which of the following?
**Core Concept**
MRP 2 (Multidrug Resistance-Associated Protein 2) is an organic anion transporter that plays a crucial role in the conjugation and excretion of bilirubin glucuronides. Conjugated hyperbilirubinemia refers to elevated levels of conjugated (direct) bilirubin in the blood, which can be caused by impaired transport or excretion of bilirubin glucuronides.
**Why the Correct Answer is Right**
MRP 2 is involved in the transport of conjugated bilirubin from hepatocytes into the bile canaliculi, where it is excreted into the intestine. Deficiency or dysfunction of MRP 2 can lead to conjugated hyperbilirubinemia due to impaired bilirubin excretion. This is often seen in Dubin-Johnson syndrome, a rare genetic disorder characterized by chronic jaundice and conjugated hyperbilirubinemia.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because MRP 2 is specifically involved in the transport of conjugated bilirubin, whereas option A is related to unconjugated bilirubin.
**Option B:** This option is incorrect because it is associated with unconjugated hyperbilirubinemia, not conjugated.
**Option C:** This option is incorrect because it is related to a different transport mechanism, not MRP 2.
**Clinical Pearl / High-Yield Fact**
Dubin-Johnson syndrome is a rare genetic disorder characterized by chronic jaundice and conjugated hyperbilirubinemia due to impaired MRP 2 function. It is often associated with dark urine and liver discoloration.
**Correct Answer:** C. Dubin-Johnson syndrome.