Neonatology: Crigler-Najjar syndrome: practice question

A Pediatrics 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.

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Pediatrics · Neonatology: Crigler-Najjar syndrome

Sample item

A neonate has severe unconjugated hyperbilirubinaemia that is unresponsive to phenobarbitone, with normal liver enzymes and no haemolysis. Which enzyme defect is responsible?

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

The answer and the reasoning

D. UGT1A1 deficiency (Crigler-Najjar type I)

Crigler-Najjar syndrome is caused by deficiency of UDP-glucuronosyltransferase 1A1, leading to severe unconjugated jaundice. Type I does not respond to phenobarbitone, while type II does.

Option by option

  • A. Deficiency of MRP2 transporter

    MRP2 defect is Dubin-Johnson syndrome and causes conjugated jaundice.

  • B. Deficiency of beta glucuronidase inhibitor

    No such inhibitor deficiency defines this condition.

  • C. G6PD deficiency

    G6PD deficiency causes haemolysis.

  • D. UGT1A1 deficiency (Crigler-Najjar type I) (correct)

    Correct. UGT1A1 deficiency causes the picture.

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.

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Questions about this Pediatrics question

What is the answer to this Pediatrics question?

The best answer is D, UGT1A1 deficiency (Crigler-Najjar type I). Crigler-Najjar syndrome is caused by deficiency of UDP-glucuronosyltransferase 1A1, leading to severe unconjugated jaundice.

Why is "Deficiency of MRP2 transporter" not the answer?

MRP2 defect is Dubin-Johnson syndrome and causes conjugated jaundice.

Why is "Deficiency of beta glucuronidase inhibitor" not the answer?

No such inhibitor deficiency defines this condition.

Why is "G6PD deficiency" not the answer?

G6PD deficiency causes haemolysis.

What concept does this question test?

It tests Neonatology: Crigler-Najjar syndrome in Pediatrics. Type I does not respond to phenobarbitone, while type II does.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. 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 Neonatology: Crigler-Najjar syndrome?

Memorise milestones and the vaccine schedule as tables and revise them often. Then use the flashcards and the other Pediatrics 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.