ADEM commonly follows a monophasic course with a favorable prognosis, but a recent report published by Hennes et al. (5) suggested that 22 of 65 MOG-abs-positive children (33.8%) experienced a clinical relapse and were diagnosed with MDEM (6), recurrent optic neuritis (RON) (7), ADEM followed by optic neuritis (ADEM-ON) (8), or neuromyelitis optica spectrum disorders (NMOSDs) (9, 10). The gene discussed is MOG; the disease is optic neuritis.