Organ System Pathology USMLE Step 1 Practice Question
An 81 year old man presents with progressive exertional dyspnea and lower extremity edema. Echocardiography shows concentric ventricular thickening with preserved ejection fraction, and ECG shows low voltage. Serum immunofixation is negative for monoclonal protein. Which of the following proteins most likely accounts for the extracellular deposits causing this condition?
Answer choices
- ACollagen type III
- BWild type or mutant transthyretinCorrect answer
- CImmunoglobulin lambda light chain
- DApolipoprotein B
- EBeta amyloid precursor protein
- FMutant apolipoprotein AI amyloid fibrils
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