Immunopathology: transthyretin amyloidosis: 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 · Immunopathology: transthyretin amyloidosis

Sample item

An 82-year-old man has heart failure with thickened ventricular walls and low-voltage ECG. Serum free light chains and immunofixation are normal. Endomyocardial biopsy shows apple-green birefringent deposits under polarised light after Congo red staining. Which protein is the likely fibril precursor?

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

The answer and the reasoning

C. Transthyretin

Wild-type transthyretin deposits in the heart of elderly men causing senile systemic (ATTR) amyloidosis, a cause of restrictive cardiomyopathy. The absence of a plasma cell clone makes AL amyloid unlikely. Mutant transthyretin causes familial amyloid polyneuropathy and cardiomyopathy.

Option by option

  • A. Immunoglobulin light chain

    AL amyloid arises from a plasma cell clone, which tests exclude here.

  • B. Serum amyloid A

    Serum amyloid A deposits in chronic inflammatory disease and affects the kidney, liver and spleen.

  • C. Transthyretin (correct)

    Correct. Wild-type transthyretin amyloid is the common cardiac amyloid in the very old.

  • D. Beta-2 microglobulin

    Beta-2 microglobulin amyloid is found in long-term dialysis patients.

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 Pathology question

What is the answer to this Pathology question?

The best answer is C, Transthyretin. Wild-type transthyretin deposits in the heart of elderly men causing senile systemic (ATTR) amyloidosis, a cause of restrictive cardiomyopathy.

Why is "Immunoglobulin light chain" not the answer?

AL amyloid arises from a plasma cell clone, which tests exclude here.

Why is "Serum amyloid A" not the answer?

Serum amyloid A deposits in chronic inflammatory disease and affects the kidney, liver and spleen.

Why is "Beta-2 microglobulin" not the answer?

Beta-2 microglobulin amyloid is found in long-term dialysis patients.

What concept does this question test?

It tests Immunopathology: transthyretin amyloidosis in Pathology. The absence of a plasma cell clone makes AL amyloid unlikely. Mutant transthyretin causes familial amyloid polyneuropathy and cardiomyopathy.

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 Immunopathology: transthyretin amyloidosis?

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.