Metabolic: maple syrup urine disease: 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.

Try it

Pediatrics · Metabolic: maple syrup urine disease

Sample item

A neonate on day 5 develops poor feeding, lethargy, encephalopathy and urine with a maple syrup odour. Which amino acids are elevated?

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

The answer and the reasoning

A. Leucine, isoleucine and valine

MSUD is a defect in branched-chain alpha-ketoacid dehydrogenase, raising leucine, isoleucine and valine, with leucine being the neurotoxic one. Treatment is a diet low in branched-chain amino acids and thiamine trial, with dialysis in crisis. Sotolone is responsible for the odour.

Option by option

  • A. Leucine, isoleucine and valine (correct)

    Correct. The branched-chain amino acids are elevated.

  • B. Methionine and homocysteine

    Methionine and homocysteine apply to homocystinuria.

  • C. Phenylalanine and tyrosine

    Phenylalanine and tyrosine apply to PKU and tyrosinaemia.

  • D. Cystine and lysine

    Cystine and lysine apply to cystinuria.

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 Pediatrics questions

Questions about this Pediatrics question

What is the answer to this Pediatrics question?

The best answer is A, Leucine, isoleucine and valine. MSUD is a defect in branched-chain alpha-ketoacid dehydrogenase, raising leucine, isoleucine and valine, with leucine being the neurotoxic one.

Why is "Methionine and homocysteine" not the answer?

Methionine and homocysteine apply to homocystinuria.

Why is "Phenylalanine and tyrosine" not the answer?

Phenylalanine and tyrosine apply to PKU and tyrosinaemia.

Why is "Cystine and lysine" not the answer?

Cystine and lysine apply to cystinuria.

What concept does this question test?

It tests Metabolic: maple syrup urine disease in Pediatrics. Treatment is a diet low in branched-chain amino acids and thiamine trial, with dialysis in crisis. Sotolone is responsible for the odour.

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 Metabolic: maple syrup urine disease?

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.