Haematology: factor V Leiden: practice question

A General Medicine 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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General Medicine · Haematology: factor V Leiden

Sample item

A 28-year-old woman has a deep vein thrombosis, a family history of venous thrombosis and normal levels of protein C, protein S and antithrombin. What is the most likely inherited cause?

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

The answer and the reasoning

C. Factor V Leiden mutation

Factor V Leiden (R506Q) makes factor Va resistant to cleavage by activated protein C and is the commonest inherited thrombophilia, particularly in people of European descent. Diagnosis is by APC resistance assay or genotyping. Deficiencies of natural anticoagulants are rarer and are excluded here by normal levels.

Option by option

  • A. Protein C deficiency

    Protein C levels are normal.

  • B. Antithrombin deficiency

    Antithrombin levels are normal.

  • C. Factor V Leiden mutation (correct)

    Correct. APC resistance from factor V Leiden is the most common cause.

  • D. Protein S deficiency

    Protein S levels are normal.

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 General Medicine question

What is the answer to this General Medicine question?

The best answer is C, Factor V Leiden mutation. Factor V Leiden (R506Q) makes factor Va resistant to cleavage by activated protein C and is the commonest inherited thrombophilia, particularly in people of European descent.

Why is "Protein C deficiency" not the answer?

Protein C levels are normal.

Why is "Antithrombin deficiency" not the answer?

Antithrombin levels are normal.

Why is "Protein S deficiency" not the answer?

Protein S levels are normal.

What concept does this question test?

It tests Haematology: factor V Leiden in General Medicine. Diagnosis is by APC resistance assay or genotyping. Deficiencies of natural anticoagulants are rarer and are excluded here by normal levels.

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 Haematology: factor V Leiden?

For each disease know the classic presentation, the best test, and the first-line treatment. Then use the flashcards and the other General Medicine 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.