Oral medicine and oral cancer: white sponge nevus genetics: practice question

A Dentistry 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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Dentistry · Oral medicine and oral cancer: white sponge nevus genetics

Sample item

A teenager has thick, folded, asymptomatic white plaques on both buccal mucosae since childhood, and a parent has similar lesions. Biopsy shows spongy acanthosis with vacuolated cells. Mutation of which gene is responsible?

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

The answer and the reasoning

D. Keratin 4 or keratin 13

White sponge nevus is an autosomal dominant disorder caused by mutations in keratin 4 or 13 of the non-keratinised mucosa. It is benign, requires no treatment and is not premalignant.

Option by option

  • A. Keratin 5 or keratin 14

    Keratin 5 and 14 mutations cause epidermolysis bullosa simplex with blistering.

  • B. Collagen type VII

    Collagen VII defects cause dystrophic epidermolysis bullosa.

  • C. Desmoglein 3

    Desmoglein 3 is the autoantigen of pemphigus vulgaris and not a mutated gene here.

  • D. Keratin 4 or keratin 13 (correct)

    Correct. White sponge nevus results from KRT4 or KRT13 mutation.

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 Dentistry question

What is the answer to this Dentistry question?

The best answer is D, Keratin 4 or keratin 13. White sponge nevus is an autosomal dominant disorder caused by mutations in keratin 4 or 13 of the non-keratinised mucosa.

Why is "Keratin 5 or keratin 14" not the answer?

Keratin 5 and 14 mutations cause epidermolysis bullosa simplex with blistering.

Why is "Collagen type VII" not the answer?

Collagen VII defects cause dystrophic epidermolysis bullosa.

Why is "Desmoglein 3" not the answer?

Desmoglein 3 is the autoantigen of pemphigus vulgaris and not a mutated gene here.

What concept does this question test?

It tests Oral medicine and oral cancer: white sponge nevus genetics in Dentistry. It is benign, requires no treatment and is not premalignant.

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 Oral medicine and oral cancer: white sponge nevus genetics?

Learn the dental formula, eruption ages and tooth structure once, as tables. Then use the flashcards and the other Dentistry 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.