In 2018, a whole-genome sequence study conducted on 215 NMOSD cases and 1244 controls of European ancestry identified two independent signals associated with NMO-IgG positivity in the major histocompatibility complex (MHC) regions, one of which is located in the HLA-DQA1 gene3. The gene discussed is HLA-DQA1; the disease is neuromyelitis optica.