Persistent MOG-Ab were observed in all disease groups: none of the NMOSD/MOG-AD patients become MOG-Ab negative during follow up compared to 50% of patients with a non-NMOSD phenotype (Median (IQR): NMOSD/MOG-AD timepoint one = 15.70 (18.1); timepoint two = 2.7 (11.1); Non-NMOSD = timepoint one = 1.6 (4.4); timepoint two = 0.9 (3.7)). This evidence concerns the gene MOG and Alzheimer disease.