Immunodeficiency: Wiskott-Aldrich syndrome: practice question

A Pathology 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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Pathology · Immunodeficiency: Wiskott-Aldrich syndrome

Sample item

A 1-year-old boy has eczema, petechiae and recurrent otitis media. His platelet count is 30,000 per microlitre, and the platelets are small on the smear. Which defect explains this triad?

AMutation of GP Ib-IX-V with giant dysfunctional plateletsBMutation of the WAS gene affecting actin cytoskeleton organisation in haematopoietic cellsCMutation of BTK with absent B cellsDDeficiency of ADAMTS13 with platelet microthrombi

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

The answer and the reasoning

B. Mutation of the WAS gene affecting actin cytoskeleton organisation in haematopoietic cells

Wiskott-Aldrich syndrome is X-linked, with defective WAS protein that regulates actin cytoskeleton, giving microthrombocytopenia (small platelets), eczema and recurrent infections. Typically IgM is low while IgA and IgE are raised. Patients are prone to autoimmunity and lymphoma and need transplantation for definitive treatment.

Option by option

A. Mutation of GP Ib-IX-V with giant dysfunctional platelets
GP Ib-IX-V mutation causes Bernard-Soulier syndrome with giant platelets and no eczema or immunodeficiency.
B. Mutation of the WAS gene affecting actin cytoskeleton organisation in haematopoietic cells (correct)
Correct. WAS protein deficiency produces the classic triad with small platelets.
C. Mutation of BTK with absent B cells
BTK mutation causes agammaglobulinaemia without eczema or thrombocytopenia.
D. Deficiency of ADAMTS13 with platelet microthrombi
ADAMTS13 deficiency causes thrombotic thrombocytopenic purpura, a microangiopathic haemolytic anaemia.

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.

Questions about this Pathology question

What is the answer to this Pathology question?

The best answer is B, Mutation of the WAS gene affecting actin cytoskeleton organisation in haematopoietic cells. Wiskott-Aldrich syndrome is X-linked, with defective WAS protein that regulates actin cytoskeleton, giving microthrombocytopenia (small platelets), eczema and recurrent infections.

Why is "Mutation of GP Ib-IX-V with giant dysfunctional platelets" not the answer?

GP Ib-IX-V mutation causes Bernard-Soulier syndrome with giant platelets and no eczema or immunodeficiency.

Why is "Mutation of BTK with absent B cells" not the answer?

BTK mutation causes agammaglobulinaemia without eczema or thrombocytopenia.

Why is "Deficiency of ADAMTS13 with platelet microthrombi" not the answer?

ADAMTS13 deficiency causes thrombotic thrombocytopenic purpura, a microangiopathic haemolytic anaemia.

What concept does this question test?

It tests Immunodeficiency: Wiskott-Aldrich syndrome in Pathology. Typically IgM is low while IgA and IgE are raised. Patients are prone to autoimmunity and lymphoma and need transplantation for definitive treatment.

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 Immunodeficiency: Wiskott-Aldrich syndrome?

Learn each disease as a bundle: cause, key histology, markers, and the clinical hallmark. Then use the flashcards and the other Pathology 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.