AQP4 and myasthenia gravis: The HLA-DQB*05:02 allele is highly associated with AQP4-positive Neuromyelitis Optica Spectrum Disorder (NMOSD) in the Chinese population (29) and is a high-risk factor for the onset of Myasthenia Gravis (30), particularly in MuSK-related Myasthenia Gravis (31).