AL amyloidosis is derived from immunoglobulin light chains. In contrast, AA amyloidosis is derived from which serum precursor protein?
- A Beta-2 microglobulin (β2M), accumulating in renal dialysis patients
- B Serum amyloid A (SAA), an acute-phase apolipoprotein synthesized by the liver ✓
- C Transthyretin (TTR), the most common hereditary amyloid precursor
- D Cystatin C, an amyloidogenic protein in Icelandic hereditary amyloidosis
Correct answer: B. Serum amyloid A (SAA), an acute-phase apolipoprotein synthesized by the liver
Explanation
AA amyloidosis (secondary amyloidosis) is derived from serum amyloid A (SAA), an acute-phase reactant apolipoprotein produced by the liver in response to chronic inflammatory stimuli (e.g., rheumatoid arthritis, IBD, familial Mediterranean fever). SAA is cleaved by monocyte enzymes into the AA fragment that forms amyloid fibrils. β2M amyloid (Aβ2M) occurs in long-term hemodialysis. TTR amyloid is hereditary or senile systemic. Cystatin C is Icelandic hereditary amyloid.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.