Third, in MS the role of MOG antibodies is still under debate, and a number of recent studies suggest that antibodies to native MOG might only be pathogenic in patients with acute disseminated encephalomyelitis (ADEM) or childhood MS [14-16], whereas they are an epiphenomenon in "classical MS" that might be related to ongoing tissue damage [18,31] or EBV infection [19]. The gene discussed is MOG; the disease is myeloid sarcoma.