Medical genetics: Lynch syndrome: 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 · Medical genetics: Lynch syndrome

Sample item

A 40-year-old woman has right-sided colon cancer, and her mother had endometrial cancer. The tumour shows microsatellite instability. Which DNA repair process is defective?

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

The answer and the reasoning

B. Mismatch repair

Lynch syndrome is caused by germline mutations in mismatch repair genes such as MLH1 and MSH2. Failure to correct replication errors leads to microsatellite instability and early colorectal and endometrial cancers.

Option by option

  • A. Homologous recombination repair

    Homologous recombination repair is defective in BRCA-related cancers.

  • B. Mismatch repair (correct)

    Correct. Defective mismatch repair produces microsatellite instability.

  • C. Nucleotide excision repair

    Nucleotide excision repair is defective in xeroderma pigmentosum.

  • D. Base excision repair

    Base excision repair is defective in MUTYH-associated polyposis.

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 Anatomy questions

Questions about this Anatomy question

What is the answer to this Anatomy question?

The best answer is B, Mismatch repair. Lynch syndrome is caused by germline mutations in mismatch repair genes such as MLH1 and MSH2.

Why is "Homologous recombination repair" not the answer?

Homologous recombination repair is defective in BRCA-related cancers.

Why is "Nucleotide excision repair" not the answer?

Nucleotide excision repair is defective in xeroderma pigmentosum.

Why is "Base excision repair" not the answer?

Base excision repair is defective in MUTYH-associated polyposis.

What concept does this question test?

It tests Medical genetics: Lynch syndrome in Anatomy. Failure to correct replication errors leads to microsatellite instability and early colorectal and endometrial cancers.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. 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 Medical genetics: Lynch syndrome?

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.