Immunology: ataxia-telangiectasia: practice question

A Microbiology 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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Microbiology · Immunology: ataxia-telangiectasia

Sample item

A 6-year-old girl has progressive gait ataxia, dilated conjunctival blood vessels and recurrent sinopulmonary infections. Which laboratory pair would be expected?

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

The answer and the reasoning

A. Raised serum alpha-fetoprotein with low IgA

Ataxia-telangiectasia is caused by mutation of the ATM gene, which is needed to sense and repair double-strand DNA breaks. It causes cerebellar ataxia, oculocutaneous telangiectasia, IgA and IgG2 deficiency, sensitivity to ionising radiation and a high risk of lymphoid malignancy. Alpha-fetoprotein is typically raised.

Option by option

  • A. Raised serum alpha-fetoprotein with low IgA (correct)

    A raised alpha-fetoprotein and low IgA are characteristic laboratory markers of this DNA repair disorder.

  • B. Raised serum IgM with low IgG and IgA

    Raised IgM with low IgG and IgA indicates hyper IgM syndrome, which lacks neurological features.

  • C. Raised serum IgE with eosinophilia

    Raised IgE with eosinophilia suggests hyper IgE syndrome or atopic disease, which does not cause ataxia.

  • D. Low serum ceruloplasmin with raised urinary copper

    Low ceruloplasmin with raised urinary copper indicates Wilson disease, which causes hepatic and basal ganglia disease, not telangiectasia.

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 Microbiology question

What is the answer to this Microbiology question?

The best answer is A, Raised serum alpha-fetoprotein with low IgA. Ataxia-telangiectasia is caused by mutation of the ATM gene, which is needed to sense and repair double-strand DNA breaks.

Why is "Raised serum IgM with low IgG and IgA" not the answer?

Raised IgM with low IgG and IgA indicates hyper IgM syndrome, which lacks neurological features.

Why is "Raised serum IgE with eosinophilia" not the answer?

Raised IgE with eosinophilia suggests hyper IgE syndrome or atopic disease, which does not cause ataxia.

Why is "Low serum ceruloplasmin with raised urinary copper" not the answer?

Low ceruloplasmin with raised urinary copper indicates Wilson disease, which causes hepatic and basal ganglia disease, not telangiectasia.

What concept does this question test?

It tests Immunology: ataxia-telangiectasia in Microbiology. It causes cerebellar ataxia, oculocutaneous telangiectasia, IgA and IgG2 deficiency, sensitivity to ionising radiation and a high risk of lymphoid malignancy. Alpha-fetoprotein is typically raised.

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 Immunology: ataxia-telangiectasia?

Make a one-line identity card for each organism: shape and stain, defining test, toxin, disease and drug. Then use the flashcards and the other Microbiology 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.