Notably, the literature suggests mGluR5’s role in guiding the differentiation of oligodendrocyte precursors into mature oligodendrocytes, which may elucidate the concurrent incidence of mGluR5 and MOG.[4] So far, MOG and mGluR5 double antibody positive encephalitis characterized by optic neuritis is extremely rare. Here, GRM5 is linked to optic neuritis.