AQP4 and neuromyelitis optica: Two weeks after, a serum autoimmune myelopathy panel sent to the Mayo Clinic was negative for amphiphysin antibody, AGNA-1, ANNA-2, ANNA-3, CRMP-5-IgG, DPPX antibody, GFAP, mGluR1, NIF, NMO/AQP4, N-type calcium channel antibody, P/Q-type calcium channel antibody, and PCA-1.