In AL (primary) amyloidosis, the amyloid precursor protein is:
- A Serum amyloid A (SAA) protein, an acute-phase reactant
- B Monoclonal immunoglobulin light chains (most commonly lambda) from plasma cell dyscrasia ✓
- C Transthyretin (TTR) produced by the liver
- D Beta-2 microglobulin accumulating in dialysis patients
Correct answer: B. Monoclonal immunoglobulin light chains (most commonly lambda) from plasma cell dyscrasia
Explanation
AL amyloidosis is the most common systemic form and arises from a plasma cell clone (multiple myeloma, MGUS, or Waldenström macroglobulinemia) that produces monoclonal immunoglobulin light chains — predominantly lambda (λ) type, which are more amyloidogenic due to specific variable region sequences (particularly VλVI domain). These light chains undergo misfolding into beta-sheet fibrils. AA amyloidosis is from SAA. ATTR (transthyretin) amyloidosis is hereditary or senile. Beta-2 microglobulin (Aβ2M) causes dialysis-related amyloidosis.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.