Skeletal dysplasias: cleidocranial dysplasia: 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 · Skeletal dysplasias: cleidocranial dysplasia

Sample item

A boy can bring both shoulders together in front of his chest. He has a large open anterior fontanelle, frontal bossing and delayed eruption of teeth. What is the diagnosis?

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

The answer and the reasoning

D. Cleidocranial dysplasia

Cleidocranial dysplasia is an autosomal dominant condition with absent or hypoplastic clavicles, delayed closure of the fontanelles and sutures, and dental anomalies. The shoulders can be approximated in front of the chest. It is caused by mutation of RUNX2.

Option by option

  • A. Achondroplasia

    Achondroplasia causes rhizomelic short limbs with a normal clavicle.

  • B. Hurler syndrome

    Hurler syndrome has corneal clouding and visceral enlargement.

  • C. Osteogenesis imperfecta

    Osteogenesis imperfecta has fragility fractures and blue sclerae.

  • D. Cleidocranial dysplasia (correct)

    Correct. Clavicular hypoplasia with fontanelle and dental changes is characteristic.

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 D, Cleidocranial dysplasia. Cleidocranial dysplasia is an autosomal dominant condition with absent or hypoplastic clavicles, delayed closure of the fontanelles and sutures, and dental anomalies.

Why is "Achondroplasia" not the answer?

Achondroplasia causes rhizomelic short limbs with a normal clavicle.

Why is "Hurler syndrome" not the answer?

Hurler syndrome has corneal clouding and visceral enlargement.

Why is "Osteogenesis imperfecta" not the answer?

Osteogenesis imperfecta has fragility fractures and blue sclerae.

What concept does this question test?

It tests Skeletal dysplasias: cleidocranial dysplasia in Orthopaedics. The shoulders can be approximated in front of the chest. It is caused by mutation of RUNX2.

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 Skeletal dysplasias: cleidocranial dysplasia?

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.