One of these is persisting MOG-IgG seropositivity throughout the disease.11 16–20 Furthermore, optic neuritis (ON), younger age in adults or early relapse within the first 12 months of onset has shown to be associated with an elevated risk of relapsing disease.21 22 However, a true predictor of a relapsing course, assessable prior to clinical relapse, is still lacking. The gene discussed is MOG; the disease is optic neuritis.