Embryology: 21-hydroxylase deficiency and Mullerian ducts: 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.

Try it

Anatomy · Embryology: 21-hydroxylase deficiency and Mullerian ducts

Sample item

A 46,XX newborn with raised 17-hydroxyprogesterone has an enlarged clitoris and fused labioscrotal folds, but ultrasound shows a uterus and ovaries. Why are the internal genital organs female?

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

The answer and the reasoning

D. No testes are present, so no anti-Mullerian hormone is made

Fetal Sertoli cells in the testis secrete anti-Mullerian hormone, which causes Mullerian duct regression. In a 46,XX fetus with congenital adrenal hyperplasia there are no testes, so the uterus and tubes develop, while excess adrenal androgens virilise the external genitalia.

Option by option

  • A. Adrenal androgens inactivate anti-Mullerian hormone

    Adrenal androgens do not inactivate anti-Mullerian hormone, which is simply not produced.

  • B. Maternal oestrogen preserves the paramesonephric ducts

    Maternal oestrogen is not the determinant of Mullerian duct persistence.

  • C. Excess androgens induce differentiation of the Mullerian ducts

    Androgens do not induce Mullerian development; they affect the Wolffian ducts and external genitalia.

  • D. No testes are present, so no anti-Mullerian hormone is made (correct)

    Correct. Without testes there is no anti-Mullerian hormone, so the paramesonephric ducts persist.

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 D, No testes are present, so no anti-Mullerian hormone is made. Fetal Sertoli cells in the testis secrete anti-Mullerian hormone, which causes Mullerian duct regression.

Why is "Adrenal androgens inactivate anti-Mullerian hormone" not the answer?

Adrenal androgens do not inactivate anti-Mullerian hormone, which is simply not produced.

Why is "Maternal oestrogen preserves the paramesonephric ducts" not the answer?

Maternal oestrogen is not the determinant of Mullerian duct persistence.

Why is "Excess androgens induce differentiation of the Mullerian ducts" not the answer?

Androgens do not induce Mullerian development; they affect the Wolffian ducts and external genitalia.

What concept does this question test?

It tests Embryology: 21-hydroxylase deficiency and Mullerian ducts in Anatomy. In a 46,XX fetus with congenital adrenal hyperplasia there are no testes, so the uterus and tubes develop, while excess adrenal androgens virilise the external genitalia.

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 Embryology: 21-hydroxylase deficiency and Mullerian ducts?

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.