GRID2 and cerebellar ataxia: Antibodies to GluRδ2 (immunoglobulin G [IgG] and M [IgM]) were first reported in 2004 in a 20-month-old child [48] and again in 2010 in two boys (18 months and 13 years of age, respectively) with cerebellar ataxia, one of whom was positive for GluRδ2-IgM instead of IgG [49, 50].