Genetic and metabolic disorders: glutaric aciduria type 1: 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 · Genetic and metabolic disorders: glutaric aciduria type 1

Sample item

A 10-month-old with a head circumference above the 97th centile and mild hypotonia develops sudden dystonia and loss of motor skills after a febrile illness. MRI shows widened Sylvian fissures with bilateral basal ganglia injury, and urine organic acids show raised glutaric and 3-hydroxyglutaric acids. Which long-term measure best prevents further striatal damage?

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

The answer and the reasoning

A. Lysine-restricted diet with carnitine and an emergency regimen during illness

Glutaric aciduria type 1 is caused by glutaryl-CoA dehydrogenase deficiency in lysine and tryptophan catabolism. Striatal injury is triggered by catabolic stress, so management combines lysine restriction, carnitine and a high-calorie emergency regimen during infections.

Option by option

  • A. Lysine-restricted diet with carnitine and an emergency regimen during illness (correct)

    Correct. Lysine restriction, carnitine and aggressive illness-time management prevent catabolic striatal injury.

  • B. Fructose and sucrose exclusion with frequent glucose supplementation

    Fructose and sucrose exclusion treats hereditary fructose intolerance, which causes hypoglycaemia and liver injury.

  • C. Phenylalanine-free formula with tetrahydrobiopterin supplementation daily

    Phenylalanine restriction and tetrahydrobiopterin treat phenylketonuria and its cofactor variants.

  • D. Leucine-restricted formula with thiamine supplementation during illnesses

    Leucine restriction with thiamine is used for maple syrup urine disease, not for this lysine pathway defect.

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 A, Lysine-restricted diet with carnitine and an emergency regimen during illness. Glutaric aciduria type 1 is caused by glutaryl-CoA dehydrogenase deficiency in lysine and tryptophan catabolism.

Why is "Fructose and sucrose exclusion with frequent glucose supplementation" not the answer?

Fructose and sucrose exclusion treats hereditary fructose intolerance, which causes hypoglycaemia and liver injury.

Why is "Phenylalanine-free formula with tetrahydrobiopterin supplementation d…" not the answer?

Phenylalanine restriction and tetrahydrobiopterin treat phenylketonuria and its cofactor variants.

Why is "Leucine-restricted formula with thiamine supplementation during illne…" not the answer?

Leucine restriction with thiamine is used for maple syrup urine disease, not for this lysine pathway defect.

What concept does this question test?

It tests Genetic and metabolic disorders: glutaric aciduria type 1 in Pediatrics. Striatal injury is triggered by catabolic stress, so management combines lysine restriction, carnitine and a high-calorie emergency regimen during infections.

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 Genetic and metabolic disorders: glutaric aciduria type 1?

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.