In anti-GBM disease (Goodpasture syndrome), autoantibodies target the non-collagenous domain 1 (NC1) of which specific collagen chain?

• A Alpha-1 chain of type IV collagen
• B Alpha-3 chain of type IV collagen ✓
• C Alpha-5 chain of type IV collagen
• D Alpha-3 chain of type II collagen

Explanation

Goodpasture syndrome is caused by autoantibodies directed against the NC1 domain of the alpha-3 chain of type IV collagen — a component predominantly expressed in the glomerular basement membrane (GBM), pulmonary alveolar basement membrane, and choroid plexus. The NC1 domain of alpha-3(IV) contains the 'Goodpasture epitope', which is normally sequestered within the supramolecular triple-helical network and becomes accessible following conformational change. This explains the pulmonary-renal syndrome: linear IgG deposits along GBM on immunofluorescence (distinguishing it from immune complex diseases with granular deposits). Type II collagen is a cartilage component unrelated to GBM.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.