In AL amyloidosis (primary amyloidosis), the fibril precursor protein is:

• A Serum amyloid A protein (an acute phase reactant)
• B Transthyretin (TTR)
• C Beta-2-microglobulin
• D Immunoglobulin light chain fragments (kappa or lambda) ✓

Explanation

AL (amyloid light chain) amyloidosis derives from monoclonal immunoglobulin light chains produced by a plasma cell dyscrasia (myeloma or Waldenström's macroglobulinemia). The light chains (more often lambda than kappa) misfold into beta-pleated sheets forming amyloid fibrils. AA amyloidosis uses serum amyloid A (from chronic inflammation); hereditary amyloidosis uses transthyretin; dialysis-related amyloidosis uses beta-2-microglobulin.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.