A 25-year-old man presents with hemoptysis and hematuria, anti-GBM antibody positive. Renal biopsy shows linear IgG deposits along the GBM and crescentic (rapidly progressive) glomerulonephritis. The antigen targeted by anti-GBM antibody is:

• A Phospholipase A2 receptor (PLA2R) on podocytes
• B Heparan sulfate proteoglycan in GBM
• C Thrombospondin type 1 domain-containing 7A (THSD7A)
• D Non-collagenous domain (NC1) of type IV collagen alpha-3 chain ✓

Explanation

Goodpasture syndrome (anti-GBM disease) is caused by autoantibodies targeting the NC1 domain of type IV collagen alpha-3 chain (COL4A3), which is uniquely expressed in GBM and alveolar basement membranes. The shared antigen explains the pulmonary-renal syndrome. Linear IgG on IF (unlike the granular pattern of immune complex GN) is pathognomonic. PLA2R is the target antigen in primary membranous nephropathy. THSD7A is the target in a subset of PLA2R-negative membranous nephropathy.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.