A 55-year-old man with a 20-year history of bronchiectasis and recurrent sinusitis presents with nephrotic syndrome. Renal biopsy shows amyloid deposits that are positive for Congo red staining. The most likely precursor protein in this patient is:
- A Transthyretin
- B Immunoglobulin light chains
- C Serum amyloid A (SAA) ✓
- D Beta-2 microglobulin
Correct answer: C. Serum amyloid A (SAA)
Explanation
Long-standing chronic inflammatory conditions like bronchiectasis cause sustained elevation of serum amyloid C (SAA), an acute-phase reactant, leading to AA (secondary/reactive) amyloidosis. AL amyloidosis arises from light chains in plasma cell dyscrasias. Transthyretin causes familial amyloidosis. Beta-2 microglobulin causes amyloidosis in long-term hemodialysis patients.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.