It is interesting in the present context that 4 of the false positives had shown a positive MRZ reaction, as typically seen in MS, one of whom had a primary-progressive disease course, which is atypical in MOG-EM but not infrequent in MS, and three of whom had a relapsing-remitting disease course; all four met the current diagnostic criteria for MS. This evidence concerns the gene MOG and myeloid sarcoma.