Typical optic neuritis is the most common presentation, especially in young adults; when atypical features are present, such as bilateral involvement, prominent optic disc edema with hemorrhages, longitudinally extended lesions on orbit MRI, and poor steroid response, it is wise to ask for serum antibodies to AQP4 and MOG, which are commonly associated with atypical ON. This evidence concerns the gene MOG and optic neuritis.