Reproduction: androgen insensitivity syndrome: practice question

A Physiology 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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Physiology · Reproduction: androgen insensitivity syndrome

Sample item

An 18-year-old with a female phenotype and well-developed breasts has scanty pubic hair, primary amenorrhoea, a blind vagina and no uterus. Karyotype is 46,XY, with high testosterone and raised LH. What explains the breasts and the absent uterus?

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

The answer and the reasoning

D. Aromatisation of testosterone to oestradiol, and regression of Mullerian ducts by testicular AMH

In complete androgen insensitivity, an androgen receptor defect prevents masculinisation, and high testosterone is aromatised to oestradiol, which causes breast development. Sertoli cells still secrete AMH, so the uterus and tubes regress, and the lack of androgen action leaves scanty body hair.

Option by option

  • A. Adrenal oestrogen excess, with atrophic Mullerian structures

    Adrenal oestrogen is not the source, and Mullerian regression is complete.

  • B. Dihydrotestosterone conversion to oestrogen, with Mullerian regression driven by hCG

    DHT is not converted to oestrogen, and hCG does not drive Mullerian regression.

  • C. Ovarian oestrogen, and absent AMH receptors causing loss of Mullerian structures

    The gonads are testes, not ovaries, and AMH receptors are functional.

  • D. Aromatisation of testosterone to oestradiol, and regression of Mullerian ducts by testicular AMH (correct)

    Correct. Both aromatisation and AMH action are intact.

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 Physiology question

What is the answer to this Physiology question?

The best answer is D, Aromatisation of testosterone to oestradiol, and regression of Mullerian ducts by testicular AMH. In complete androgen insensitivity, an androgen receptor defect prevents masculinisation, and high testosterone is aromatised to oestradiol, which causes breast development.

Why is "Adrenal oestrogen excess, with atrophic Mullerian structures" not the answer?

Adrenal oestrogen is not the source, and Mullerian regression is complete.

Why is "Dihydrotestosterone conversion to oestrogen, with Mullerian regressio…" not the answer?

DHT is not converted to oestrogen, and hCG does not drive Mullerian regression.

Why is "Ovarian oestrogen, and absent AMH receptors causing loss of Mullerian…" not the answer?

The gonads are testes, not ovaries, and AMH receptors are functional.

What concept does this question test?

It tests Reproduction: androgen insensitivity syndrome in Physiology. Sertoli cells still secrete AMH, so the uterus and tubes regress, and the lack of androgen action leaves scanty body hair.

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 Reproduction: androgen insensitivity syndrome?

For each system, sketch the key graph (pressure–volume loop, oxygen dissociation curve, nephron handling) and explain it aloud. Then use the flashcards and the other Physiology 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.