Medical genetics: Klinefelter syndrome diagnosis: 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.

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Anatomy · Medical genetics: Klinefelter syndrome diagnosis

Sample item

A tall 24-year-old man with infertility has gynaecomastia, small firm testes and azoospermia. FSH and LH are raised and testosterone is low. Which test confirms the cause?

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

The answer and the reasoning

D. Peripheral blood karyotype

The picture of hypergonadotropic hypogonadism with small firm testes suggests Klinefelter syndrome, usually 47,XXY. A standard peripheral blood karyotype confirms the diagnosis.

Option by option

  • A. Y chromosome microdeletion analysis

    Y microdeletion analysis is used in unexplained azoospermia but does not explain the gynaecomastia and tall stature.

  • B. CFTR mutation analysis

    CFTR analysis is for congenital absence of the vas deferens, with normal gonadotropins and normal testes.

  • C. FISH for the SRY gene

    SRY FISH is used to detect Y material in disorders of sex development.

  • D. Peripheral blood karyotype (correct)

    Correct. Karyotyping shows the extra X chromosome.

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 Anatomy question

What is the answer to this Anatomy question?

The best answer is D, Peripheral blood karyotype. The picture of hypergonadotropic hypogonadism with small firm testes suggests Klinefelter syndrome, usually 47,XXY.

Why is "Y chromosome microdeletion analysis" not the answer?

Y microdeletion analysis is used in unexplained azoospermia but does not explain the gynaecomastia and tall stature.

Why is "CFTR mutation analysis" not the answer?

CFTR analysis is for congenital absence of the vas deferens, with normal gonadotropins and normal testes.

Why is "FISH for the SRY gene" not the answer?

SRY FISH is used to detect Y material in disorders of sex development.

What concept does this question test?

It tests Medical genetics: Klinefelter syndrome diagnosis in Anatomy. A standard peripheral blood karyotype confirms the diagnosis.

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 Medical genetics: Klinefelter syndrome diagnosis?

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.