Clinical biochemistry: Gilbert syndrome: practice question

A Biochemistry question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

Try it

Biochemistry · Clinical biochemistry: Gilbert syndrome

Sample item

A 19-year-old has mild jaundice during fasting and intercurrent illness. Unconjugated bilirubin is 2.8 mg/dL, liver enzymes and blood count are normal, there is no haemolysis and the urine contains no bilirubin. What is the molecular basis?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

D. Reduced hepatic UGT1A1 expression from a promoter variant

Gilbert syndrome is a benign condition with reduced expression of bilirubin UDP-glucuronosyltransferase, commonly from a TA-repeat promoter variant. Unconjugated bilirubin rises with fasting, stress or illness. No treatment is needed.

Option by option

  • A. Absent canalicular MRP2 transporter

    MRP2 loss causes Dubin-Johnson syndrome with conjugated hyperbilirubinaemia.

  • B. Defective hepatic uptake by OATP1B1 and OATP1B3

    Loss of both uptake transporters causes Rotor syndrome with mainly conjugated hyperbilirubinaemia.

  • C. Increased haem oxygenase activity

    Overactive haem oxygenase would require haemolysis or increased haem turnover.

  • D. Reduced hepatic UGT1A1 expression from a promoter variant (correct)

    Correct. Reduced UGT1A1 gives mild unconjugated hyperbilirubinaemia that worsens on fasting.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

More Biochemistry questions

Questions about this Biochemistry question

What is the answer to this Biochemistry question?

The best answer is D, Reduced hepatic UGT1A1 expression from a promoter variant. Gilbert syndrome is a benign condition with reduced expression of bilirubin UDP-glucuronosyltransferase, commonly from a TA-repeat promoter variant.

Why is "Absent canalicular MRP2 transporter" not the answer?

MRP2 loss causes Dubin-Johnson syndrome with conjugated hyperbilirubinaemia.

Why is "Defective hepatic uptake by OATP1B1 and OATP1B3" not the answer?

Loss of both uptake transporters causes Rotor syndrome with mainly conjugated hyperbilirubinaemia.

Why is "Increased haem oxygenase activity" not the answer?

Overactive haem oxygenase would require haemolysis or increased haem turnover.

What concept does this question test?

It tests Clinical biochemistry: Gilbert syndrome in Biochemistry. Unconjugated bilirubin rises with fasting, stress or illness. No treatment is needed.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Clinical biochemistry: Gilbert syndrome?

Build one table of enzyme deficiency, disease, inheritance and key finding, then revise it by spaced recall. Then use the flashcards and the other Biochemistry questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.