Histology: skin and desmosomes: 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 · Histology: skin and desmosomes

Sample item

A 45-year-old man has flaccid blisters, painful oral erosions and a positive Nikolsky sign. Biopsy shows a suprabasal split with a row of intact basal cells attached to the dermis, like a row of tombstones. Autoantibodies are directed against which structure?

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

The answer and the reasoning

C. Desmosomes between keratinocytes (desmoglein)

In pemphigus vulgaris, IgG against desmoglein 3 (with or without desmoglein 1) breaks desmosomal adhesion in the lower stratum spinosum, producing acantholysis and a suprabasal blister. Basal cells stay attached through hemidesmosomes. Subepidermal blistering diseases target hemidesmosomes or anchoring fibrils.

Option by option

  • A. Hemidesmosomes at the dermo-epidermal junction (BP180)

    Hemidesmosome antibodies (BP180) cause bullous pemphigoid with a subepidermal split.

  • B. Anchoring fibrils made of type VII collagen

    Type VII collagen antibodies cause epidermolysis bullosa acquisita with a subepidermal split.

  • C. Desmosomes between keratinocytes (desmoglein) (correct)

    Correct. Desmoglein is the cadherin of the desmosome, and its loss produces suprabasal acantholysis.

  • D. Gap junctions between keratinocytes (connexin)

    Gap junction proteins are not the autoimmune target in pemphigus.

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, Desmosomes between keratinocytes (desmoglein). In pemphigus vulgaris, IgG against desmoglein 3 (with or without desmoglein 1) breaks desmosomal adhesion in the lower stratum spinosum, producing acantholysis and a suprabasal blister.

Why is "Hemidesmosomes at the dermo-epidermal junction (BP180)" not the answer?

Hemidesmosome antibodies (BP180) cause bullous pemphigoid with a subepidermal split.

Why is "Anchoring fibrils made of type VII collagen" not the answer?

Type VII collagen antibodies cause epidermolysis bullosa acquisita with a subepidermal split.

Why is "Gap junctions between keratinocytes (connexin)" not the answer?

Gap junction proteins are not the autoimmune target in pemphigus.

What concept does this question test?

It tests Histology: skin and desmosomes in Anatomy. Basal cells stay attached through hemidesmosomes. Subepidermal blistering diseases target hemidesmosomes or anchoring fibrils.

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 Histology: skin and desmosomes?

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.