Paediatric orthopaedics: pseudoachondroplasia: practice question

A Orthopaedics 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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Orthopaedics · Paediatric orthopaedics: pseudoachondroplasia

Sample item

A 5-year-old has short-limbed dwarfism and a waddling gait, with irregular, fragmented epiphyses and flared metaphyses on radiographs. Her skull, head size and facial features are entirely normal. Which diagnosis fits best?

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

The answer and the reasoning

B. Pseudoachondroplasia

Pseudoachondroplasia is caused by mutations in COMP (cartilage oligomeric matrix protein). Stature is short from early childhood, the face is normal, and epiphyseal and metaphyseal irregularity leads to early osteoarthritis. Achondroplasia is due to FGFR3 mutation and has frontal bossing and midface hypoplasia.

Option by option

  • A. Achondroplasia

    Achondroplasia typically has frontal bossing, midface hypoplasia and a large head.

  • B. Pseudoachondroplasia (correct)

    Correct. Short limbs with epiphyseal and metaphyseal irregularity and a normal face point to pseudoachondroplasia.

  • C. Hypochondroplasia

    Hypochondroplasia is a milder FGFR3 disorder with mild limb shortening and narrowing of the lumbar interpedicular distance.

  • D. Spondyloepiphyseal dysplasia congenita

    Spondyloepiphyseal dysplasia congenita presents earlier with a short trunk, flat face and myopia, and has vertebral changes.

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 Orthopaedics question

What is the answer to this Orthopaedics question?

The best answer is B, Pseudoachondroplasia. Pseudoachondroplasia is caused by mutations in COMP (cartilage oligomeric matrix protein).

Why is "Achondroplasia" not the answer?

Achondroplasia typically has frontal bossing, midface hypoplasia and a large head.

Why is "Hypochondroplasia" not the answer?

Hypochondroplasia is a milder FGFR3 disorder with mild limb shortening and narrowing of the lumbar interpedicular distance.

Why is "Spondyloepiphyseal dysplasia congenita" not the answer?

Spondyloepiphyseal dysplasia congenita presents earlier with a short trunk, flat face and myopia, and has vertebral changes.

What concept does this question test?

It tests Paediatric orthopaedics: pseudoachondroplasia in Orthopaedics. Stature is short from early childhood, the face is normal, and epiphyseal and metaphyseal irregularity leads to early osteoarthritis. Achondroplasia is due to FGFR3 mutation and has frontal bossing and midface hypoplasia.

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 Paediatric orthopaedics: pseudoachondroplasia?

Pair each fracture with its classic complication and nerve injured. Then use the flashcards and the other Orthopaedics 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.