Vesiculobullous: junctional epidermolysis bullosa: practice question

A Dermatology 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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Dermatology · Vesiculobullous: junctional epidermolysis bullosa

Sample item

A neonate has widespread blisters, nail dystrophy and granulation tissue around the mouth. Electron microscopy shows a split in the lamina lucida. A defect in which protein is most likely?

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

The answer and the reasoning

C. Laminin 332

Junctional epidermolysis bullosa arises from mutations in laminin 332 (laminin 5), or collagen XVII, causing cleavage in the lamina lucida. The severe Herlitz form is often fatal in infancy. Keratin 5 and 14 mutations cause simplex EB with a split in the basal layer, and type VII collagen defects cause dystrophic EB below the lamina densa.

Option by option

  • A. Keratin 5 and 14

    Keratin 5 and 14 defects give an intraepidermal basal split in EB simplex.

  • B. Desmoglein 3

    Desmoglein 3 is the target in pemphigus vulgaris, an acquired disease.

  • C. Laminin 332 (correct)

    Correct. Laminin 332 defects cause a lamina lucida split.

  • D. Type VII collagen

    Type VII collagen defects split below the lamina densa in dystrophic EB.

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 Dermatology questions

Questions about this Dermatology question

What is the answer to this Dermatology question?

The best answer is C, Laminin 332. Junctional epidermolysis bullosa arises from mutations in laminin 332 (laminin 5), or collagen XVII, causing cleavage in the lamina lucida.

Why is "Keratin 5 and 14" not the answer?

Keratin 5 and 14 defects give an intraepidermal basal split in EB simplex.

Why is "Desmoglein 3" not the answer?

Desmoglein 3 is the target in pemphigus vulgaris, an acquired disease.

Why is "Type VII collagen" not the answer?

Type VII collagen defects split below the lamina densa in dystrophic EB.

What concept does this question test?

It tests Vesiculobullous: junctional epidermolysis bullosa in Dermatology. The severe Herlitz form is often fatal in infancy. Keratin 5 and 14 mutations cause simplex EB with a split in the basal layer, and type VII collagen defects cause dystrophic EB below the lamina densa.

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 Vesiculobullous: junctional epidermolysis bullosa?

Learn each condition by its primary lesion, site and signature sign. Then use the flashcards and the other Dermatology 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.