Medical genetics: Williams syndrome: practice question

A Anatomy 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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Anatomy · Medical genetics: Williams syndrome

Sample item

A child has an elfin face, a very sociable personality, supravalvular aortic stenosis and hypercalcaemia. Which cytogenetic abnormality is responsible?

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

The answer and the reasoning

C. Microdeletion of 7q11.23 involving the elastin gene

Williams syndrome results from a contiguous gene deletion at 7q11.23 that includes the elastin gene, which explains the supravalvular aortic stenosis. It can be shown by FISH. Deletion of 22q11.2 causes DiGeorge syndrome and 15q11-q13 causes Prader-Willi syndrome.

Option by option

  • A. Deletion of the short arm of chromosome 5

    A 5p deletion causes cri-du-chat syndrome.

  • B. Deletion of paternal 15q11-q13

    A paternal 15q11-q13 deletion causes Prader-Willi syndrome.

  • C. Microdeletion of 7q11.23 involving the elastin gene (correct)

    Correct. A 7q11.23 deletion containing elastin causes Williams syndrome.

  • D. Microdeletion of 22q11.2

    A 22q11.2 deletion causes DiGeorge or velocardiofacial 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.

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Questions about this Anatomy question

What is the answer to this Anatomy question?

The best answer is C, Microdeletion of 7q11.23 involving the elastin gene. Williams syndrome results from a contiguous gene deletion at 7q11.

Why is "Deletion of the short arm of chromosome 5" not the answer?

A 5p deletion causes cri-du-chat syndrome.

Why is "Deletion of paternal 15q11-q13" not the answer?

A paternal 15q11-q13 deletion causes Prader-Willi syndrome.

Why is "Microdeletion of 22q11.2" not the answer?

A 22q11.2 deletion causes DiGeorge or velocardiofacial syndrome.

What concept does this question test?

It tests Medical genetics: Williams syndrome in Anatomy. 23 that includes the elastin gene, which explains the supravalvular aortic stenosis. It can be shown by FISH. Deletion of 22q11.2 causes DiGeorge syndrome and 15q11-q13 causes Prader-Willi syndrome.

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 Medical genetics: Williams syndrome?

Learn every nerve by its route, its muscles and what a lesion looks like at the bedside. That one habit answers a large share of questions. Then use the flashcards and the other Anatomy 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.