A 45-year-old woman with ovarian teratoma develops sub-acute cerebellar degeneration. Serum anti-Yo (anti-PCA-1) antibodies are detected. What is the target antigen of these antibodies in cerebellar Purkinje cells?
- A Voltage-gated calcium channels (VGCC)
- B CDR2 and CDR2L proteins expressed ectopically on the tumor ✓
- C NMDA receptor NR1 subunit
- D Amphiphysin protein at presynaptic terminals
Correct answer: B. CDR2 and CDR2L proteins expressed ectopically on the tumor
Explanation
Anti-Yo (PCA-1) antibodies target CDR2 (cerebellar degeneration-related protein 2) and the related CDR2L, which are normally expressed in Purkinje cells but are aberrantly expressed by gynecological tumors (ovarian, breast). The immune response triggered against the ectopically expressed antigen cross-reacts with Purkinje cells, causing paraneoplastic cerebellar degeneration. Anti-NMDAR encephalitis is associated with NMDA receptor antibodies, and VGCC antibodies associate with Lambert-Eaton myasthenic syndrome.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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