Organ System Pathology USMLE Step 1 Practice Question
A 46-year-old woman with severe rheumatoid arthritis presents with progressive bilateral lower extremity edema and heavy proteinuria (4.2 g/day). Vital signs show BP 142/88 mmHg, HR 88/min, RR 16/min, temp 37.2°C. Serum creatinine is 1.8 mg/dL. Renal biopsy demonstrates Congo red positive, birefringent deposits in the glomerular mesangium and vessel walls. Urinalysis shows no hematuria. Which protein is the most likely precursor of these deposits?
Answer choices
- AMutant transthyretin
- BImmunoglobulin light chains
- CBeta 2 microglobulin
- DIslet amyloid polypeptide
- ESerum amyloid ACorrect answer
- FApolipoprotein B-100
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