Medical genetics: androgen insensitivity: 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 · Medical genetics: androgen insensitivity

Sample item

A phenotypic female has primary amenorrhoea with normal breast development, scant pubic and axillary hair, a blind-ending vagina and testes in the inguinal canals. Her karyotype is 46,XY and a maternal aunt is similarly affected. What is the mode of inheritance?

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

The answer and the reasoning

A. X-linked recessive

Complete androgen insensitivity is caused by mutations of the androgen receptor gene on the X chromosome. It is passed through carrier mothers to 46,XY offspring, who develop as phenotypic females.

Option by option

  • A. X-linked recessive (correct)

    Correct. The androgen receptor gene lies on the X chromosome and the trait runs through maternal relatives.

  • B. Y-linked

    Y-linked inheritance would pass from father to son and would not involve a maternal aunt.

  • C. Autosomal dominant

    Autosomal dominant inheritance would affect both parents' lines and both sexes in each generation.

  • D. Autosomal recessive

    Autosomal recessive inheritance is not suggested by the affected maternal relative and the 46,XY-only expression.

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 A, X-linked recessive. Complete androgen insensitivity is caused by mutations of the androgen receptor gene on the X chromosome.

Why is "Y-linked" not the answer?

Y-linked inheritance would pass from father to son and would not involve a maternal aunt.

Why is "Autosomal dominant" not the answer?

Autosomal dominant inheritance would affect both parents' lines and both sexes in each generation.

Why is "Autosomal recessive" not the answer?

Autosomal recessive inheritance is not suggested by the affected maternal relative and the 46,XY-only expression.

What concept does this question test?

It tests Medical genetics: androgen insensitivity in Anatomy. It is passed through carrier mothers to 46,XY offspring, who develop as phenotypic females.

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: androgen insensitivity?

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.