Pigmentary disorders: piebaldism: 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 · Pigmentary disorders: piebaldism

Sample item

A boy has a white forelock and symmetric depigmented patches on the abdomen and limbs since birth, with islands of normal pigment inside them. Which gene is mutated?

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

The answer and the reasoning

C. KIT

Piebaldism is autosomal dominant and results from loss-of-function mutations in KIT, impairing melanoblast migration, so patches lack melanocytes. Unlike vitiligo, it is present from birth and is stable.

Option by option

  • A. TYR

    TYR mutation causes albinism.

  • B. MITF only

    MITF mutation is linked to Waardenburg syndrome type 2, which has deafness.

  • C. KIT (correct)

    Correct. KIT mutation causes piebaldism.

  • D. FLG

    FLG mutation causes ichthyosis vulgaris.

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, KIT. Piebaldism is autosomal dominant and results from loss-of-function mutations in KIT, impairing melanoblast migration, so patches lack melanocytes.

Why is "TYR" not the answer?

TYR mutation causes albinism.

Why is "MITF only" not the answer?

MITF mutation is linked to Waardenburg syndrome type 2, which has deafness.

Why is "FLG" not the answer?

FLG mutation causes ichthyosis vulgaris.

What concept does this question test?

It tests Pigmentary disorders: piebaldism in Dermatology. Unlike vitiligo, it is present from birth and is stable.

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 Pigmentary disorders: piebaldism?

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.