Oral medicine and oral cancer: dyskeratosis congenita: 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: dyskeratosis congenita

Sample item

A boy has nail dystrophy, reticulate hyperpigmentation of the neck and chest, leukoplakia of the tongue and progressive pancytopenia. Which basic defect underlies this disorder?

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

The answer and the reasoning

A. Defective telomere maintenance

Dyskeratosis congenita is caused by defects in telomere maintenance, such as mutations of the telomerase components. Patients have the mucocutaneous triad, marrow failure and a high risk of squamous cell carcinoma, often of the tongue.

Option by option

  • A. Defective telomere maintenance (correct)

    Correct. Telomere maintenance defects underlie dyskeratosis congenita.

  • B. Defective collagen VII anchoring

    Collagen VII defects cause dystrophic epidermolysis bullosa.

  • C. Defective nucleotide excision repair

    Defective nucleotide excision repair causes xeroderma pigmentosum with photosensitivity.

  • D. Defective interstrand crosslink repair

    Crosslink repair defects cause Fanconi anaemia, which has skeletal anomalies instead of the mucocutaneous triad.

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 A, Defective telomere maintenance. Dyskeratosis congenita is caused by defects in telomere maintenance, such as mutations of the telomerase components.

Why is "Defective collagen VII anchoring" not the answer?

Collagen VII defects cause dystrophic epidermolysis bullosa.

Why is "Defective nucleotide excision repair" not the answer?

Defective nucleotide excision repair causes xeroderma pigmentosum with photosensitivity.

Why is "Defective interstrand crosslink repair" not the answer?

Crosslink repair defects cause Fanconi anaemia, which has skeletal anomalies instead of the mucocutaneous triad.

What concept does this question test?

It tests Oral medicine and oral cancer: dyskeratosis congenita in Dentistry. Patients have the mucocutaneous triad, marrow failure and a high risk of squamous cell carcinoma, often of the tongue.

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: dyskeratosis congenita?

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.