Co-existing autoimmune diseases and/or autoantibodies, especially Sjögren syndrome, anti-nuclear antibody (ANA), and anti-SS-A/SS-B antibodies, were more frequent in NMOSD patients compared with MS patients (all p < 0.001), while frequencies of co-existing thyroid disease and/or thyroid-related antibodies did not differ between the two groups. The gene discussed is SSB; the disease is autoimmune disease.