Patients previously diagnosed with Neuromyelitis Optica, Neuromyelitis Optica Spectrum Disorder, Transverse Myelitis and Optic Neuritis and healthy controls will be eligible to participate in this study. Males and females six years and older, who are either able to consent for themselves or where the parent is able to give informed consent, and who are able to maintain scheduled visits to University of Texas Southwestern Medical Center will be recruited in this study. Patients will donate serum, plasma, DNA, RNA and white blood cells. There is no monetary compensation. There is no cost to you. You will not receive any personal health benefits as a result of your participation in this observational research study. We hope that the results will help us better identify new ways of diagnosing and treating these disorders. Your participation is voluntary.