Plasticity-related gene 5: A novel surface autoantigen in paraneoplastic cerebellar degeneration

Paraneoplastic cerebellar degeneration (PCD) is one of the most frequent paraneoplastic syndromes affecting the CNS. It is associated with antibodies targeting intracellular neuronal antigens (Hu, Yo, Ri, CV2/CRMP5), which are not thought to be directly pathogenic, and surface antigens (DNER, mGluR1, VGCC), which are potentially pathogenic.1,2 However, in many patients the immunologic target remains unidentified, resulting in diagnostic and therapeutic challenges. We report a patient with PCD and a squamous cell lung carcinoma with antibodies to a novel neuronal surface antigen, plasticity-related gene 5 (PRG5).