Furthermore, the analyses within these studies were performed by combining not only patients who were aquaporin‐4‐antibody (AQP4‐Ab) positive but also ‘seronegative’ NMOSD patients,9, 11, 12, 13, 14, 15 which is likely to comprise different pathological conditions including myelin oligodendrocyte glycoprotein‐antibody (MOG‐Ab) disease, atypical MS and other autoimmune and connective tissue diseases. The gene discussed is MOG; the disease is glycogen storage disease VI.