AQP4 and neuromyelitis optica: In the present study we used CRISPR/Cas9 technology to generate an AQP4ex−/− mouse model and evaluate the effect on the overall AQP4 expression, polarization, supramolecular organization in orthogonal arrays of particles (OAPs) and neuromyelitis optica (NMO-IgG) autoantibodies binding.