Genetic and metabolic disorders: Morquio 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.

Try it

Pediatrics · Genetic and metabolic disorders: Morquio syndrome

Sample item

A 6-year-old has short-trunk dwarfism, pectus carinatum, genu valgum, corneal clouding and normal intelligence. Neck films show odontoid hypoplasia. Which glycosaminoglycans are excreted in excess in urine?

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

The answer and the reasoning

D. Keratan sulfate and chondroitin 6-sulfate

Morquio syndrome (MPS IV) is characterised by skeletal dysplasia, normal intelligence and odontoid hypoplasia that risks atlantoaxial subluxation and cord compression. The urinary glycosaminoglycans are keratan sulfate and chondroitin 6-sulfate.

Option by option

  • A. Dermatan sulfate and heparan sulfate together

    Dermatan and heparan sulfate excretion is seen in Hurler and Hunter syndromes, with intellectual disability and coarse facies.

  • B. Dermatan sulfate alone with normal heparan sulfate

    Dermatan sulfate alone is the pattern of Maroteaux-Lamy syndrome, with normal intelligence but not this keratan sulfate skeletal picture.

  • C. Heparan sulfate alone with normal dermatan sulfate

    Heparan sulfate alone is the pattern of Sanfilippo syndrome, with severe behavioural and cognitive decline.

  • D. Keratan sulfate and chondroitin 6-sulfate (correct)

    Correct. Keratan sulfate with chondroitin 6-sulfate is excreted in Morquio syndrome.

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 D, Keratan sulfate and chondroitin 6-sulfate. Morquio syndrome (MPS IV) is characterised by skeletal dysplasia, normal intelligence and odontoid hypoplasia that risks atlantoaxial subluxation and cord compression.

Why is "Dermatan sulfate and heparan sulfate together" not the answer?

Dermatan and heparan sulfate excretion is seen in Hurler and Hunter syndromes, with intellectual disability and coarse facies.

Why is "Dermatan sulfate alone with normal heparan sulfate" not the answer?

Dermatan sulfate alone is the pattern of Maroteaux-Lamy syndrome, with normal intelligence but not this keratan sulfate skeletal picture.

Why is "Heparan sulfate alone with normal dermatan sulfate" not the answer?

Heparan sulfate alone is the pattern of Sanfilippo syndrome, with severe behavioural and cognitive decline.

What concept does this question test?

It tests Genetic and metabolic disorders: Morquio syndrome in Pediatrics. The urinary glycosaminoglycans are keratan sulfate and chondroitin 6-sulfate.

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 Genetic and metabolic disorders: Morquio 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.