Concept of health and disease: genetic counselling: practice question

A PSM 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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PSM · Concept of health and disease: genetic counselling

Sample item

Both parents are carriers of an autosomal recessive disease. What is the chance that each child will be affected?

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

The answer and the reasoning

C. 25 percent

Two carriers of an autosomal recessive condition have a 25 percent chance of an affected child, 50 percent chance of a carrier child and 25 percent chance of an unaffected non-carrier in each pregnancy. The risk is the same each time.

Option by option

  • A. 12.5 percent

    12.5 percent is not the risk for each child.

  • B. 50 percent

    50 percent is the chance of a carrier child.

  • C. 25 percent (correct)

    Correct. One in four for each pregnancy.

  • D. 100 percent

    100 percent would need both parents affected.

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 PSM questions

Questions about this PSM question

What is the answer to this PSM question?

The best answer is C, 25 percent. Two carriers of an autosomal recessive condition have a 25 percent chance of an affected child, 50 percent chance of a carrier child and 25 percent chance of an unaffected non-carrier in each pregnancy.

Why is "12.5 percent" not the answer?

12.5 percent is not the risk for each child.

Why is "50 percent" not the answer?

50 percent is the chance of a carrier child.

Why is "100 percent" not the answer?

100 percent would need both parents affected.

What concept does this question test?

It tests Concept of health and disease: genetic counselling in PSM. The risk is the same each time.

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 Concept of health and disease: genetic counselling?

Practise biostatistics with small calculations until sensitivity, predictive values and risk measures are automatic. Then use the flashcards and the other PSM 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.